خودکشی و آسیب شناسی روانی برونسازی در یک نمونه سراسری

Suicide is most often associated with internalizing disorders such as depression; however, recent evidence suggests that externalizing psychopathology (substance dependence disorders, antisocial personality disorder) may have an independent relationship with suicidal behavior. The aim in the present study was to examine the relationship between lifetime suicide attempts and lifetime externalizing psychopathology in the US National Comorbidity Survey data set (n = 5877). First, hierarchical regression was performed to explore the associations between internalizing and externalizing disorders and suicide attempts. Externalizing psychopathology was significantly associated with lifetime suicide attempts (adjusted odds ratio = 3.47; P < .001) and significantly improved the model beyond that including only the sociodemographic variables and internalizing psychopathology (χ2 difference = 73.12; df = 1; P < .001). A second logistic regression was used to investigate the association between specific patterns of psychopathology and suicidality. Externalizing disorders were significantly associated with suicide attempts even in the absence of internalizing disorders (adjusted odds ratio = 5.98; 95% confidence interval = 3.07-11.67; P < .001). These findings add to the growing literature that suggests that externalizing psychopathology is an important psychiatric correlate of suicidal behavior.

Suicide was the second leading cause of death in the United States in 2000 for people 25 to 34 years old and the third leading cause of death for people 15 to 24 years old [1] and [2]. Identifying psychiatric factors uniquely associated with suicidal behavior is important to improve the ability to predict suicide risk and to facilitate effective and timely mental health service delivery. Using data from the US National Comorbidity Survey (NCS), Kessler et al [3] completed one of the largest studies on the prevalence and correlates of suicidal behavior. The lifetime prevalence of suicide attempts in this nationally representative sample was 4.6%. Among the sociodemographic variables assessed in the NCS, Kessler et al found that suicide attempts were strongly associated with being a woman, having been previously married, being born in a recent cohort (eg, year of birth between 1966 and 1975), and having a low education level. One of the most robust correlates of suicide attempts identified has been psychopathology [4], [5], [6], [7], [8] and [9]. Kessler et al found the association between suicide attempts and psychopathology to be substantially higher for mood disorders than for any other disorder. For example, the odds ratio for major depression was 11.0 compared with 5.7 for antisocial personality disorder and 5.6 for panic disorder. Thus, it is not surprising that investigations into psychiatric correlates of suicide have typically focused on internalizing psychopathology such as unipolar depression [4], [8], [10], [11], [12] and [13]. An association between externalizing disorders (substance dependence disorders and antisocial personality disorder) and suicidal behavior has been demonstrated in adolescent and adult populations [5], [14], [15], [16], [17], [18], [19] and [20]. Verona et al [20] used a recently developed framework for understanding psychopathology identified by Krueger [21]. By applying confirmatory factor analysis to the wide range of individual diagnoses assessed in the NCS, Krueger identified an internalizing factor and an externalizing factor. He also found that the internalizing factor was composed of 2 subfactors: anxious-misery disorders and fear disorders. Verona et al [20] examined the effects of unique and comorbid internalizing and externalizing psychopathology in relation to suicide attempts. They used a large community sample that extended previous research limited to selective samples of forensic and psychiatric patients (eg, Refs. [14], [15], [16], [17] and [19]). The main finding from this new study was that externalizing disorders were related to suicide attempts, both independently and when comorbid with internalizing disorders [20]. This novel and important finding has significant clinical implications. At present, externalizing disorders, especially when not comorbid with internalizing disorders, are typically not a focus of attention in psychiatric assessment for suicide risk. The findings of Verona et al reflect the need for further research and clinical attention in this area. The NCS public use data set provides a unique opportunity to extend this line of research to a nationally representative sample. The NCS included a detailed and reliable assessment of a broad range of psychiatric disorders in addition to assessing lifetime suicidal behavior [21] and [22]. The purpose of the present study was to attempt to replicate the Verona et al research on associations between externalizing disorders and suicide attempts and to extend it to the general population. In addition, Verona et al only examined the higher-order factor of internalizing disorders in their investigation. Within this higher-order factor, one might expect anxious-misery disorders (eg, major depression) to have a stronger relationship with suicidality than do fear disorders such as phobias [10], [23], [24] and [25]. Therefore, the 2 internalizing subfactors were investigated separately. Two statistical approaches were undertaken in our investigation. First, hierarchical logistic regression was used to determine whether or not externalizing psychopathology could account for unique variance in suicide attempts beyond that contributed by internalizing disorders. The inclusion of internalizing disorders in earlier steps of the hierarchical regression provided a very stringent test of the association between externalizing disorders and suicidal behaviors. Second, a logistic regression was performed to examine the associations of comorbid externalizing disorders with suicide attempts and of pure externalizing disorders with suicide attempts. Unlike in the study of Verona et al [20], both subfactors of internalizing disorders (ie, fear disorders and anxious-misery disorders) were considered in these analyses. It was hypothesized that externalizing psychopathology would be significantly associated with suicide behavior even after adjusting for the effects of internalizing psychopathology. It was further hypothesized that both pure and comorbid anxious-misery and externalizing disorders would be significantly associated with suicide attempts.