THE IMPACT OF ADOLESCENT SUICIDE ON SIBLINGS AND FRIENDS
Aikaterini Samiotou, MSc
The history of completed suicide coexists with the history of the human being. “Completed suicide occurs when a lethal method and clear intention to die coincide; or what was assumed to be a non-lethal method does in fact kill the individual; or when anticipated rescue fails”(Bagley & Ramsay 1997). International studies, in an attempt to understand the suicide, have been interested in the appearance of suicidal behavior among different nations and countries. The questions more often asked are whether there are similarities and differences in the patterns of suicide, in the age and sex and how this information can lead to a better insight of suicidal behavior and of the factors that can play a predisposing, precipitating, maintaining and protective role. Indeed the results provided present differences in the characteristics and the methods of suicide as well as in the ages and the sex among the different countries (Shaffer & Gutstein 2004). Very interesting findings, regarding the impact of the social environment, arise when the protective role of religion and religious commitment against the risk of suicide is indicated (Hilton et al. 2002). The powerful function of the social environment can be viewed in behaviors, such as self-immolation of a widow as a way of connection with her husband or self-disembowelment as a sign of self –control and loyalty, which are to an extent culturally accepted (Cheng & Lee 2000).
One of the most vulnerable for suicide age groups is adolescence. In this developmental period the young person faces many different challenges. In his attempt to formulate his personal identity and find his own place in the different systems in which he takes part the young person displays risk behaviors. The importance of identifying the possible cases of suicide and come to a potential understanding of the suicidal model becomes strongly significant when it is estimated that in many countries suicide is the one of the three commonest causes of death in the age group 15-34 (World Health Organization 1999). Males appear more likely to engage in completed suicide while females in attempted suicide and suicide ideation (Center for Disease Control, National Center for Injury prevention and Control 2004).
Suicide as a completed action is not as common as the attempted suicide (deliberate self-harm, parasuicide) which appears in much higher rates and it is estimated to be one thousand times commoner (Goodman & Scott 2005). The strong association and risk though between previous attempt to suicide and subsequent completed suicide that appears to range between 0.24% and 4.30% (Hawton & James 2005) consists of a very significant indicator of the importance to recognize the multiple motivations behind this action. An increased number of current research studies, as a part of the above need, have been attempting to point out the characteristics of persons who commit suicide. One of the factors that have proved to be very significant in contributing to a higher risk of completed suicide is the environment around the adolescent and in particular the family and the peer group. Indeed a review of the current bibliography underlines the major role that the family and the friends of adolescent can play, a role that can act as predisposing or precipitant as well as protective against the risk of suicide.
Family
Regarding the family factor a home environment based in disrupted relationships among the members, psychiatric disorder in family members and family history of suicide have all proved to be strongly associated with the risk of suicide (Goodman &Scott 2005). The causal role of family factor in the risk of suicide is complex and cannot be easily interpreted. One of the most powerful indicators of suicide risk is the history of completed suicide in the same family. The familial clustering of suicide has been documented by different studies (Qin et al. 2002). The mechanism however of the familial aggregation of the suicide is not clear. The role of the family psychopathology has been associated with the familial transmission of suicide (Runeson & Asperg 2003). Given that the above association is not clear, the role of genetics in the transmission has been emphasized (Roy et al. 1995). As a part of the above aim to understand the mechanism of familial inheritance of suicide the role of shared environmental and psychosocial factors has been highlighted and proved significant (Gould et al. 1996).
Friends
Evidence based researches have shown that the event of suicide can be associated with subsequent suicide risk among the friends (Cerel et al. 2005). A relationship between exposure to a friend’s suicide and higher rates of suicide risk has been documented in different studies. The most common explanation for the increased suicide risk after a peer’s suicide is the imitation and a contagion hypothesis has been reported (Brent et al. 1992). Apart from the role of imitation in the suicidal clustering among friends, the role of personal and family psychiatric vulnerability in the increased risk of suicide after the exposure to suicide has been well documented (Brent et al. 1993; Ho et al. 2000).
While aiming to understand the possible factors that influence the individual’s decision to end his life, it is crucial to consider the possible motivations for this action. Interestingly what appears to be one of the strongest motivations for suicide and deliberate self- harm is the desire to hurt others and make them feel guilty (Hawton & James 2005). Actually while we search for the reasons that lead to suicide, we tend to underestimate the strong influence of suicide on the loved ones (Cantor 2000). Indeed the body of research that focuses on the suicide reports that apart from the elevated risk for subsequent suicide, the action itself has devastating effects on the environment around the victim (Pfeffer et al. 1997). More specifically, studies focusing on siblings exposed to their adolescent relative’s suicidal death, report that these survivors present significant psychiatric symptoms, social impairment and severe grief symptomatology (Brent et al. 1993; Brent et al. 1996). In respect to the adolescents exposed to a friend’s suicidal death, studies demonstrate the deleterious impact of this event on their psychiatric well –being and psychosocial functioning (Cerel et al. 2005).
Based on the above evidence the questions that arise are the following:
What is the level of our knowledge about what happens after suicide? Can being a sibling of an adolescent that committed suicide be considered as a risk factor for later suicide or suicide attempts? Does being a member of the same peer group raise the possibilities of following the same model and react in the same pattern? What are the possible explanations for the increased suicide risk in siblings and friends after the suicidal death? Is the increased risk of suicide the only way that these victims influence their siblings and their peer group? In what level do the adolescent victims of suicide hurt their environment and particularly their siblings and friends? Is there an increased risk in social impairment? What is the impact of the suicide in terms of subsequent psychopathology for the siblings and friends? What expressions does the bereavement procedure take after this way of loss? Is the level of impact the same among the two groups of the environment? Finally in terms of mental health problems why should we be concerned about the persons that have to cope with the loss?
This literature review is inspired of these questions and is based on the following hypothesis: The completed suicide of an adolescent can provoke strong emotional, behavioral and social impairment on the siblings and on the friends. In both groups an increased risk of subsequent suicidal behavior as well as an increase in psychiatric symptomatology is expected. Additionally it is hypothesized that both groups’ social functioning will be negatively affected. Especially, it is estimated that the siblings will demonstrate more significant and lasting psychopathology and social impairment.
Keeping this hypothesis in mind, this literature review aims to report the evidence regarding the impact of an adolescent’s death by suicide on the siblings and peers exposed to that death. The impact is divided in 3 parts:
1. In terms of increased subsequent suicide risk for the siblings and peers. The possible explanations behind this risk are discussed thoroughly.
2. In terms of risk of psychopathology and psychiatric symptoms that siblings and peers can develop after the suicide.
3. Impact of the loss on the bereavement procedure.
An additional aim is to demonstrate the current role of prevention programs for suicide and discuss the implication of this knowledge in order to promote the effectiveness of these programs and prevention strategies.
Family as a risk factor
One of the most devastating impacts of completed suicide in the family is its association with an increased risk for subsequent suicide behavior (attempted and completed suicides). Brent and colleagues in their study, presenting an increase in the rates of suicidal behavior in the first- degree relatives of 58 adolescent suicide victims compared with the relatives of a control group, supported the familial transmission of suicide (Brent et al. 1996). Several studies have also supported the familial nature of suicide (Shafii et al. 1985). Runeson presented evidence for familial liability to suicide, demonstrating that 38% of the suicide victims had a first -degree relative (parent or sibling) with history of suicide attempt and completed suicide (Runeson et al. 1996). Supporting evidence regarding the familial transference of suicidal behavior has been reported in a study designed to estimate the prevalence of attempted and completed suicide among the families of teenage suicide victims. In 40% of men a family history of suicide was proved to be apparent while 31% of women female had a first-degree relative that had displayed suicidal behaviour (Runeson 1998). Similar findings presenting the likelihood of suicide victims to have first-degree relatives with a history of attempted and completed suicide compared to the control group were presented in a psychological autopsy study (Cheng et al. 2000).
Based on the evidence that present the siblings and the relatives of suicide victims in an increased risk for suicide, the nature and origins of familial transmission of suicide became a major controversy in different studies.
Psychopathology as a way of transmission of suicide
The familial inheritance of suicide has been well attributed to the transmission of psychopathology. Shaffer and colleagues in their study aiming to explore the suicide’s relationship with the psychopathology compared 120 of 170 teenagers who committed suicide with community control subjects. The study’s conclusion was that more than 90% of the suicide victims presented at least one psychiatric disorder with mood, disruptive and substance abuse disorders being the most common compared to the control group (Shaffer et al. 1996). The strong liaison between suicide and psychopathology was demonstrated in a psychological autopsy study of a group of suicide victims aged 15-24. In this group the rates of psychopathology were high (74 %) with depressive disorder being the most common. Most victims presented significant problems with alcohol and drug abuse and co- morbidity of psychiatric and personality disorders. According to this study more than half of this young group had a family history of psychiatric disorder (Hawton et al 1999). The familial clustering of suicidal behaviour and different psychiatric disorders was supported in a community sample of adolescents. Higher rates of any Axis 1 disorder, substance abuse and suicidal behaviour were apparent among the first- degree relatives of the sample. Higher prevalence of psychiatric conditions such as affective disorder, conduct disorder and anxiety disorder were also associated with the first-degree relatives although the above association proved not statistically significant (Bridge et al. 1997).
Apart from the studies that demonstrate the familial inheritance of suicide as a part of the familial continuum of psychopathology, there are other studies that question this evidence and present the familial transmission of suicide as genetically influenced and independent of any psychiatric diagnosis.
Egeland and Sussex studied 26 suicides over 100 years the majority of whom (92%) had a diagnosis of major affective disorder. They reported that the majority of suicides (73%) occurred in four families which presented a high family loading for psychiatric disorders and especially affective disorders. The important finding though was the families that presented also a high loading for affective disorders but didn’t demonstrate any suicidal behaviour. This finding signified that the factors associated with the suicide in the family could be independent of the transmission of psychiatric disorders (Egeland & Sussex 1985). Qin et al aimed in their study to assess whether a family history of completed suicide and mental illness interact in the transmission of suicide or act independently. Including 4262 people aged 9-45 years who had committed suicide the researchers demonstrated that family history of committed suicide and mental disorder significantly and independently increased the risk of suicide. Thus, the independent role of family history of suicide in the transmission of suicide has been documented (Qin et al. 2002). The important but not the exclusive association of psychopathology with the increased rates of suicidal behaviour among the first–degree relatives of suicide victims has been reported by Brent and his colleagues. The authors argued that a liability to suicide- related behaviours may be attributed to familial transmission independently of mental illness. The familial loading for suicide behaviour was associated with higher rates of aggression among the suicide victims (Brent et al. 1996). Similar findings presenting the familial aggregation of suicide as transmitted irrespectively of psychopathology were reported in a different study (Johnson et al. 1998).
Since the familial clustering of suicidal behaviour cannot be solely associated to the familial transmission of psychopathology, different twin and adoption studies aimed to understand the different genetic factors underlying the suicide.
The role of genetics
Roy et al aiming to understand the role of the genetics in familial clustering of suicide behaviour studied 176 twin pairs in which one of two had committed suicide. Among the 62 monozygotic twin pairs, seven were found concordant for suicide while two were found among the 114 dizygotic pairs (Roy et al. 1991). Similar findings regarding the genetic role in suicide have been reported in a study of an adolescent female twin sample. The authors, after providing evidence that the rate for suicide attempts was higher in monozygotic twins compared to dizygotic, concluded that after controlling for psychopathology, genetic factors play a major role in familial aggregation of suicide (Glowinski et al. 2001). Roy and colleagues provided evidence for the genetic role in the transmission of suicide using living co-twins whose twin had committed suicide. The living monozygotic co-twins had higher rates of suicide attempts (10 of the 26) while the 9 dizygotic pairs had demonstrated 0 suicide attempts (Roy et al. 1995). In a different study depressed patients with personal history of suicide attempts and their relatives were interviewed. Using a computational model they authors concluded that the familial loading for suicide is based in polygenic rather than single gene transmission (Papadimitriou et al. 1991). Oppositional findings presented in a follow-up study of twins, lead the authors to argue that the twins were in a reduced risk of suicide, demonstrating the role of family commitments and ties in the reduction of suicide (Tomassini et al. 2003). Schulsinger and colleagues while studying 5,483 adoption cases found 57 cases that committed suicide and compared this sample with adopted control group. The suicide group had 12 biological relatives who had committed suicide compared to 2 biological relatives of the adopted control group, supporting the genetic liability for suicide (Schulsinger et al. 1979 cited by Roy et al. 2000).
Serotonin hypothesis
In a review aiming to describe the current knowledge regarding the neurobiology of suicide, the role of serotonin in the disposition to suicide has been highlighted (Kamali et al. 2001). This review reports studies that suggest that a deficient serotonin input in the ventral and ventrolateral prefrontal cortex leads to a decreased inhibitory function of this cortex and is responsible for a predisposition to impulsivity and aggressive behaviour. This serotonin dysregulation and especially alterations in 5-HT1A and 5-HT2A receptors are reported to be present in suicide and severe suicide attempts (Arango et al. 1997). Low levels of cerebrospinal fluid 5-HIAA are reported to be associated to an abnormality in the gene for tryptophan hydroxylase (TPH), the rate-limiting enzyme for the synthesis of serotonin (Zametkin et al. 2001). An association of serotonin transporter gene polymorphism with family history of completed suicide was demonstrated in a recent study (Joiner et al. 2002). Despite these studies that report the serotonin abnormality hypothesis, there are still unanswered questions and the results are far from conclusive (Shaffer & Gustein 2004).
These studies have demonstrated the role of the genetic factor in the familial inheritance of suicide independently of psychiatric disorders. The exact way and the nature of this genetic transmission though has not yet been defined (Kamali et al. 2001). While describing a model for the understanding of suicidal behaviour, Mann and colleagues recognised the factor aggression/ impulsivity as a factor that significantly differentiate the suicide attempters from the non attempters and consisted of risk feature for suicidal behaviour regardless of the psychiatric diagnosis. Therefore they proposed a stress-diathesis model where apart from the psychopathology, the impulsivity as diathesis can increase the suicide risk by increasing the likelihood of acting impulsively in suicidal thoughts and feelings. The low levels of serotonin activity had been considered that may lead to the increased aggressive and impulsive reactions under stressful situations (Mann et al. 1999).
Given the above evidence a significant association between the completed suicide and the subsequent suicide risk among the family survivors and especially the siblings arises. The familial transmission of suicide has been supported by studies in terms of psychopathology, genetic liability and abnormalities. However the mechanism that connects the above factors with suicide is not clear. Thus, the above association cannot be considered as causally affected. The familial clustering of suicide can also be viewed under the spectrum of shared environmental experiences in the family.
Socioenvironmental factors
The importance of socioenvironmental factors in the contribution of suicide risk has been demonstrated in different studies. The core factors that were proved to contribute independently in the suicide risk after adjusting for psychopathology include:
Poor relationships with parents and negative life events
The suicide victims had an increased likelihood to come from a nonintact family of origin and reported poor and less satisfying communication with their mother and father. Apart from the family history of mental illness and suicidal behaviour, the suicide victims had experienced more negative life events such as disciplinary crisis or interpersonal loss, recent separation of the parents, difficulties at school or at work (Gould et al. 1996). The significance of the loss events as risk factors for suicide risk have been reported in a study focused on the social and psychiatric factors for suicide (Cheng et al. 2000).
Unemployment, single parenthood, poor education and economic factors
Family history of unemployment, a single parent, a father with poor education, having a mother who has emigrated and low income proved to be associated with the risk of suicide in young people. However, the effect of these socioeconomic factors proved not significant after adjustment for history of psychopathology and suicide in the family (Agerbo et al. 2002). A national register-based study has indicated the role of factors such as unemployment, low income and marital status in the suicide risk (Qin et al. 2003).
Dysfunctional family system patterns and exposure to suicide
A type of suicidal process in young people, based on longstanding psychopathology, substance abuse, psychosocial stressors (problems in the relationships with parents, discord between partners, problems at work) complicated personal relationships and exposure to suicide-related behaviours in the family has been indicated (Runeson et al. 1996). The impact of the psychological and family systems patterns such as disorganization, breakup, substance abuse and family violence in the familial clustering of suicide is mentioned in an article related to suicide bereavement. The author reports that these family factors can be associated to the suicidal death and that they may have an impact in the increase of suicide risk for the other family members as well. The role of exposure to suicide in the family as a way of increasing the suicide risk among the exposed survivors is discussed in the same study (Jordan 2001).
Brent et al. in their study concluded that there is a liaison between the familial inheritance of suicide and aggression in the family (Brent et al. 1996). Apart from the possible underlying genetic factors that affect aggression and impulsivity, familial factors and early life experiences play a significant role in reinforcement of these traits (Mann et al. 1999). The association between family loading for suicide behaviour and family transmission of suicidal behaviour has been tested in a different study. The above association was confirmed as the offspring of suicide attempters with siblings concordant for suicidal behaviour appeared to be at highest risk for suicidal behaviour and presented the highest levels of impulsive aggression compared to offspring with non suicidal siblings and offspring of non suicidal families. The transmission of impulsive aggression has been considered as a possible pathway for the aggregation of suicide in the families (Brent et al. 2003). The role of aggression in the transmission of suicide has been demonstrated in a recent study where the first degree relatives of suicide completers presented significantly higher levels of aggression compared to the relatives of the control group (Kim et al. 2005).
This review aimed to present the studies that demonstrate the connection between the completed suicide of an adolescent and elevated risk for subsequent suicidal behaviour in the siblings as well as the models that these different studies use in order to understand and justify the nature of this connection.
The history of completed suicide coexists with the history of the human being. “Completed suicide occurs when a lethal method and clear intention to die coincide; or what was assumed to be a non-lethal method does in fact kill the individual; or when anticipated rescue fails”(Bagley & Ramsay 1997). International studies, in an attempt to understand the suicide, have been interested in the appearance of suicidal behavior among different nations and countries. The questions more often asked are whether there are similarities and differences in the patterns of suicide, in the age and sex and how this information can lead to a better insight of suicidal behavior and of the factors that can play a predisposing, precipitating, maintaining and protective role. Indeed the results provided present differences in the characteristics and the methods of suicide as well as in the ages and the sex among the different countries (Shaffer & Gutstein 2004). Very interesting findings, regarding the impact of the social environment, arise when the protective role of religion and religious commitment against the risk of suicide is indicated (Hilton et al. 2002). The powerful function of the social environment can be viewed in behaviors, such as self-immolation of a widow as a way of connection with her husband or self-disembowelment as a sign of self –control and loyalty, which are to an extent culturally accepted (Cheng & Lee 2000).
One of the most vulnerable for suicide age groups is adolescence. In this developmental period the young person faces many different challenges. In his attempt to formulate his personal identity and find his own place in the different systems in which he takes part the young person displays risk behaviors. The importance of identifying the possible cases of suicide and come to a potential understanding of the suicidal model becomes strongly significant when it is estimated that in many countries suicide is the one of the three commonest causes of death in the age group 15-34 (World Health Organization 1999). Males appear more likely to engage in completed suicide while females in attempted suicide and suicide ideation (Center for Disease Control, National Center for Injury prevention and Control 2004).
Suicide as a completed action is not as common as the attempted suicide (deliberate self-harm, parasuicide) which appears in much higher rates and it is estimated to be one thousand times commoner (Goodman & Scott 2005). The strong association and risk though between previous attempt to suicide and subsequent completed suicide that appears to range between 0.24% and 4.30% (Hawton & James 2005) consists of a very significant indicator of the importance to recognize the multiple motivations behind this action. An increased number of current research studies, as a part of the above need, have been attempting to point out the characteristics of persons who commit suicide. One of the factors that have proved to be very significant in contributing to a higher risk of completed suicide is the environment around the adolescent and in particular the family and the peer group. Indeed a review of the current bibliography underlines the major role that the family and the friends of adolescent can play, a role that can act as predisposing or precipitant as well as protective against the risk of suicide.
Family
Regarding the family factor a home environment based in disrupted relationships among the members, psychiatric disorder in family members and family history of suicide have all proved to be strongly associated with the risk of suicide (Goodman &Scott 2005). The causal role of family factor in the risk of suicide is complex and cannot be easily interpreted. One of the most powerful indicators of suicide risk is the history of completed suicide in the same family. The familial clustering of suicide has been documented by different studies (Qin et al. 2002). The mechanism however of the familial aggregation of the suicide is not clear. The role of the family psychopathology has been associated with the familial transmission of suicide (Runeson & Asperg 2003). Given that the above association is not clear, the role of genetics in the transmission has been emphasized (Roy et al. 1995). As a part of the above aim to understand the mechanism of familial inheritance of suicide the role of shared environmental and psychosocial factors has been highlighted and proved significant (Gould et al. 1996).
Friends
Evidence based researches have shown that the event of suicide can be associated with subsequent suicide risk among the friends (Cerel et al. 2005). A relationship between exposure to a friend’s suicide and higher rates of suicide risk has been documented in different studies. The most common explanation for the increased suicide risk after a peer’s suicide is the imitation and a contagion hypothesis has been reported (Brent et al. 1992). Apart from the role of imitation in the suicidal clustering among friends, the role of personal and family psychiatric vulnerability in the increased risk of suicide after the exposure to suicide has been well documented (Brent et al. 1993; Ho et al. 2000).
While aiming to understand the possible factors that influence the individual’s decision to end his life, it is crucial to consider the possible motivations for this action. Interestingly what appears to be one of the strongest motivations for suicide and deliberate self- harm is the desire to hurt others and make them feel guilty (Hawton & James 2005). Actually while we search for the reasons that lead to suicide, we tend to underestimate the strong influence of suicide on the loved ones (Cantor 2000). Indeed the body of research that focuses on the suicide reports that apart from the elevated risk for subsequent suicide, the action itself has devastating effects on the environment around the victim (Pfeffer et al. 1997). More specifically, studies focusing on siblings exposed to their adolescent relative’s suicidal death, report that these survivors present significant psychiatric symptoms, social impairment and severe grief symptomatology (Brent et al. 1993; Brent et al. 1996). In respect to the adolescents exposed to a friend’s suicidal death, studies demonstrate the deleterious impact of this event on their psychiatric well –being and psychosocial functioning (Cerel et al. 2005).
Based on the above evidence the questions that arise are the following:
What is the level of our knowledge about what happens after suicide? Can being a sibling of an adolescent that committed suicide be considered as a risk factor for later suicide or suicide attempts? Does being a member of the same peer group raise the possibilities of following the same model and react in the same pattern? What are the possible explanations for the increased suicide risk in siblings and friends after the suicidal death? Is the increased risk of suicide the only way that these victims influence their siblings and their peer group? In what level do the adolescent victims of suicide hurt their environment and particularly their siblings and friends? Is there an increased risk in social impairment? What is the impact of the suicide in terms of subsequent psychopathology for the siblings and friends? What expressions does the bereavement procedure take after this way of loss? Is the level of impact the same among the two groups of the environment? Finally in terms of mental health problems why should we be concerned about the persons that have to cope with the loss?
This literature review is inspired of these questions and is based on the following hypothesis: The completed suicide of an adolescent can provoke strong emotional, behavioral and social impairment on the siblings and on the friends. In both groups an increased risk of subsequent suicidal behavior as well as an increase in psychiatric symptomatology is expected. Additionally it is hypothesized that both groups’ social functioning will be negatively affected. Especially, it is estimated that the siblings will demonstrate more significant and lasting psychopathology and social impairment.
Keeping this hypothesis in mind, this literature review aims to report the evidence regarding the impact of an adolescent’s death by suicide on the siblings and peers exposed to that death. The impact is divided in 3 parts:
1. In terms of increased subsequent suicide risk for the siblings and peers. The possible explanations behind this risk are discussed thoroughly.
2. In terms of risk of psychopathology and psychiatric symptoms that siblings and peers can develop after the suicide.
3. Impact of the loss on the bereavement procedure.
An additional aim is to demonstrate the current role of prevention programs for suicide and discuss the implication of this knowledge in order to promote the effectiveness of these programs and prevention strategies.
Family as a risk factor
One of the most devastating impacts of completed suicide in the family is its association with an increased risk for subsequent suicide behavior (attempted and completed suicides). Brent and colleagues in their study, presenting an increase in the rates of suicidal behavior in the first- degree relatives of 58 adolescent suicide victims compared with the relatives of a control group, supported the familial transmission of suicide (Brent et al. 1996). Several studies have also supported the familial nature of suicide (Shafii et al. 1985). Runeson presented evidence for familial liability to suicide, demonstrating that 38% of the suicide victims had a first -degree relative (parent or sibling) with history of suicide attempt and completed suicide (Runeson et al. 1996). Supporting evidence regarding the familial transference of suicidal behavior has been reported in a study designed to estimate the prevalence of attempted and completed suicide among the families of teenage suicide victims. In 40% of men a family history of suicide was proved to be apparent while 31% of women female had a first-degree relative that had displayed suicidal behaviour (Runeson 1998). Similar findings presenting the likelihood of suicide victims to have first-degree relatives with a history of attempted and completed suicide compared to the control group were presented in a psychological autopsy study (Cheng et al. 2000).
Based on the evidence that present the siblings and the relatives of suicide victims in an increased risk for suicide, the nature and origins of familial transmission of suicide became a major controversy in different studies.
Psychopathology as a way of transmission of suicide
The familial inheritance of suicide has been well attributed to the transmission of psychopathology. Shaffer and colleagues in their study aiming to explore the suicide’s relationship with the psychopathology compared 120 of 170 teenagers who committed suicide with community control subjects. The study’s conclusion was that more than 90% of the suicide victims presented at least one psychiatric disorder with mood, disruptive and substance abuse disorders being the most common compared to the control group (Shaffer et al. 1996). The strong liaison between suicide and psychopathology was demonstrated in a psychological autopsy study of a group of suicide victims aged 15-24. In this group the rates of psychopathology were high (74 %) with depressive disorder being the most common. Most victims presented significant problems with alcohol and drug abuse and co- morbidity of psychiatric and personality disorders. According to this study more than half of this young group had a family history of psychiatric disorder (Hawton et al 1999). The familial clustering of suicidal behaviour and different psychiatric disorders was supported in a community sample of adolescents. Higher rates of any Axis 1 disorder, substance abuse and suicidal behaviour were apparent among the first- degree relatives of the sample. Higher prevalence of psychiatric conditions such as affective disorder, conduct disorder and anxiety disorder were also associated with the first-degree relatives although the above association proved not statistically significant (Bridge et al. 1997).
Apart from the studies that demonstrate the familial inheritance of suicide as a part of the familial continuum of psychopathology, there are other studies that question this evidence and present the familial transmission of suicide as genetically influenced and independent of any psychiatric diagnosis.
Egeland and Sussex studied 26 suicides over 100 years the majority of whom (92%) had a diagnosis of major affective disorder. They reported that the majority of suicides (73%) occurred in four families which presented a high family loading for psychiatric disorders and especially affective disorders. The important finding though was the families that presented also a high loading for affective disorders but didn’t demonstrate any suicidal behaviour. This finding signified that the factors associated with the suicide in the family could be independent of the transmission of psychiatric disorders (Egeland & Sussex 1985). Qin et al aimed in their study to assess whether a family history of completed suicide and mental illness interact in the transmission of suicide or act independently. Including 4262 people aged 9-45 years who had committed suicide the researchers demonstrated that family history of committed suicide and mental disorder significantly and independently increased the risk of suicide. Thus, the independent role of family history of suicide in the transmission of suicide has been documented (Qin et al. 2002). The important but not the exclusive association of psychopathology with the increased rates of suicidal behaviour among the first–degree relatives of suicide victims has been reported by Brent and his colleagues. The authors argued that a liability to suicide- related behaviours may be attributed to familial transmission independently of mental illness. The familial loading for suicide behaviour was associated with higher rates of aggression among the suicide victims (Brent et al. 1996). Similar findings presenting the familial aggregation of suicide as transmitted irrespectively of psychopathology were reported in a different study (Johnson et al. 1998).
Since the familial clustering of suicidal behaviour cannot be solely associated to the familial transmission of psychopathology, different twin and adoption studies aimed to understand the different genetic factors underlying the suicide.
The role of genetics
Roy et al aiming to understand the role of the genetics in familial clustering of suicide behaviour studied 176 twin pairs in which one of two had committed suicide. Among the 62 monozygotic twin pairs, seven were found concordant for suicide while two were found among the 114 dizygotic pairs (Roy et al. 1991). Similar findings regarding the genetic role in suicide have been reported in a study of an adolescent female twin sample. The authors, after providing evidence that the rate for suicide attempts was higher in monozygotic twins compared to dizygotic, concluded that after controlling for psychopathology, genetic factors play a major role in familial aggregation of suicide (Glowinski et al. 2001). Roy and colleagues provided evidence for the genetic role in the transmission of suicide using living co-twins whose twin had committed suicide. The living monozygotic co-twins had higher rates of suicide attempts (10 of the 26) while the 9 dizygotic pairs had demonstrated 0 suicide attempts (Roy et al. 1995). In a different study depressed patients with personal history of suicide attempts and their relatives were interviewed. Using a computational model they authors concluded that the familial loading for suicide is based in polygenic rather than single gene transmission (Papadimitriou et al. 1991). Oppositional findings presented in a follow-up study of twins, lead the authors to argue that the twins were in a reduced risk of suicide, demonstrating the role of family commitments and ties in the reduction of suicide (Tomassini et al. 2003). Schulsinger and colleagues while studying 5,483 adoption cases found 57 cases that committed suicide and compared this sample with adopted control group. The suicide group had 12 biological relatives who had committed suicide compared to 2 biological relatives of the adopted control group, supporting the genetic liability for suicide (Schulsinger et al. 1979 cited by Roy et al. 2000).
Serotonin hypothesis
In a review aiming to describe the current knowledge regarding the neurobiology of suicide, the role of serotonin in the disposition to suicide has been highlighted (Kamali et al. 2001). This review reports studies that suggest that a deficient serotonin input in the ventral and ventrolateral prefrontal cortex leads to a decreased inhibitory function of this cortex and is responsible for a predisposition to impulsivity and aggressive behaviour. This serotonin dysregulation and especially alterations in 5-HT1A and 5-HT2A receptors are reported to be present in suicide and severe suicide attempts (Arango et al. 1997). Low levels of cerebrospinal fluid 5-HIAA are reported to be associated to an abnormality in the gene for tryptophan hydroxylase (TPH), the rate-limiting enzyme for the synthesis of serotonin (Zametkin et al. 2001). An association of serotonin transporter gene polymorphism with family history of completed suicide was demonstrated in a recent study (Joiner et al. 2002). Despite these studies that report the serotonin abnormality hypothesis, there are still unanswered questions and the results are far from conclusive (Shaffer & Gustein 2004).
These studies have demonstrated the role of the genetic factor in the familial inheritance of suicide independently of psychiatric disorders. The exact way and the nature of this genetic transmission though has not yet been defined (Kamali et al. 2001). While describing a model for the understanding of suicidal behaviour, Mann and colleagues recognised the factor aggression/ impulsivity as a factor that significantly differentiate the suicide attempters from the non attempters and consisted of risk feature for suicidal behaviour regardless of the psychiatric diagnosis. Therefore they proposed a stress-diathesis model where apart from the psychopathology, the impulsivity as diathesis can increase the suicide risk by increasing the likelihood of acting impulsively in suicidal thoughts and feelings. The low levels of serotonin activity had been considered that may lead to the increased aggressive and impulsive reactions under stressful situations (Mann et al. 1999).
Given the above evidence a significant association between the completed suicide and the subsequent suicide risk among the family survivors and especially the siblings arises. The familial transmission of suicide has been supported by studies in terms of psychopathology, genetic liability and abnormalities. However the mechanism that connects the above factors with suicide is not clear. Thus, the above association cannot be considered as causally affected. The familial clustering of suicide can also be viewed under the spectrum of shared environmental experiences in the family.
Socioenvironmental factors
The importance of socioenvironmental factors in the contribution of suicide risk has been demonstrated in different studies. The core factors that were proved to contribute independently in the suicide risk after adjusting for psychopathology include:
Poor relationships with parents and negative life events
The suicide victims had an increased likelihood to come from a nonintact family of origin and reported poor and less satisfying communication with their mother and father. Apart from the family history of mental illness and suicidal behaviour, the suicide victims had experienced more negative life events such as disciplinary crisis or interpersonal loss, recent separation of the parents, difficulties at school or at work (Gould et al. 1996). The significance of the loss events as risk factors for suicide risk have been reported in a study focused on the social and psychiatric factors for suicide (Cheng et al. 2000).
Unemployment, single parenthood, poor education and economic factors
Family history of unemployment, a single parent, a father with poor education, having a mother who has emigrated and low income proved to be associated with the risk of suicide in young people. However, the effect of these socioeconomic factors proved not significant after adjustment for history of psychopathology and suicide in the family (Agerbo et al. 2002). A national register-based study has indicated the role of factors such as unemployment, low income and marital status in the suicide risk (Qin et al. 2003).
Dysfunctional family system patterns and exposure to suicide
A type of suicidal process in young people, based on longstanding psychopathology, substance abuse, psychosocial stressors (problems in the relationships with parents, discord between partners, problems at work) complicated personal relationships and exposure to suicide-related behaviours in the family has been indicated (Runeson et al. 1996). The impact of the psychological and family systems patterns such as disorganization, breakup, substance abuse and family violence in the familial clustering of suicide is mentioned in an article related to suicide bereavement. The author reports that these family factors can be associated to the suicidal death and that they may have an impact in the increase of suicide risk for the other family members as well. The role of exposure to suicide in the family as a way of increasing the suicide risk among the exposed survivors is discussed in the same study (Jordan 2001).
Brent et al. in their study concluded that there is a liaison between the familial inheritance of suicide and aggression in the family (Brent et al. 1996). Apart from the possible underlying genetic factors that affect aggression and impulsivity, familial factors and early life experiences play a significant role in reinforcement of these traits (Mann et al. 1999). The association between family loading for suicide behaviour and family transmission of suicidal behaviour has been tested in a different study. The above association was confirmed as the offspring of suicide attempters with siblings concordant for suicidal behaviour appeared to be at highest risk for suicidal behaviour and presented the highest levels of impulsive aggression compared to offspring with non suicidal siblings and offspring of non suicidal families. The transmission of impulsive aggression has been considered as a possible pathway for the aggregation of suicide in the families (Brent et al. 2003). The role of aggression in the transmission of suicide has been demonstrated in a recent study where the first degree relatives of suicide completers presented significantly higher levels of aggression compared to the relatives of the control group (Kim et al. 2005).
This review aimed to present the studies that demonstrate the connection between the completed suicide of an adolescent and elevated risk for subsequent suicidal behaviour in the siblings as well as the models that these different studies use in order to understand and justify the nature of this connection.
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