Alcoholism is a potent risk factor for suicide and attempted suicide, yet there is a paucity of controlled data on the factors that distinguish alcoholics who take their own lives or make medically serious suicide attempts. To address this gap in knowledge, the investigators will conduct secondary analyses on a dataset gathered in the Canterbury region of New Zealand between 1991 and 1994 for the Canterbury Suicide Project (CSP). The CSP identified and collected data on adult suicide victims (N=193) and medically serious suicide attempters (N=240) and a community control group (N=984). Diagnostic data using best-estimate methods including DSM-III-R alcohol dependence (past month) are available. Data on other diagnoses (mood, psychotic, antisocial personality, drug use disorders), stressful life events, and personality traits were also gathered.
In Aim 1, two predisposing factors, major depression and antisocial personality disorder (ASP), will be investigated as potential moderators (effect modifiers) of the association between alcoholism and suicidal behavior.
In Aim 2, two precipitating factors, conjugal disruptions and other stressful life events, will be evaluated as potential mediators (intermediate effects) of the relationship between alcoholism and suicidal behavior, and between ASP and suicidal behavior. Primary analyses will be based on polytmous regression models and specifically, unordered logistic regression models with two case groups (suicides, serious attempts) and a reference group (community controls). This will allow for direct comparisons between each case group and the reference group as well as between the case groups. Results will be expressed in terms of odds ratios and asymmetric confidence intervals. Goodness-of-fit will be assessed using standard procedures. Secondary analyses will include estimates of relative risk and population attributable risk for suicide and serious attempts associated with alcohol dependence and other diagnostic conditions, and explore potential gender differences in risk factors for suicidal behavior.
