Two hundred ninety-five (79.5%) of the subjects had a diagnosis of major depressive disorder, and 76 (20.5%) had bipolar disorder, currently depressed. There were 189 subjects (50.9%) with a lifetime history of a suicide attempt. One hundred seventy-five (47.2%) had a history of substance use disorder. The mean clinical ratings were 20.1 (SD=6.2) on the Hamilton depression scale, 28.1 (SD=11.4) on the Beck Depression Inventory, and 36.3 (SD=8.1) on the BPRS. Among the subjects who reported a religious affiliation (N=305), the specific denominations endorsed were Catholicism (41.0%, N=125), Protestantism (28.5%, N=87), Judaism (17.4%, N=53), and other (13.1%, N=40).
Effect of Religious Affiliation in Subjects With Depression
Subjects with no religious affiliation were more often lifetime suicide attempters, reported more suicidal ideation, and were more likely to have first-degree relatives who had committed suicide than religiously affiliated subjects.
The religiously affiliated and unaffiliated subjects did not differ in terms of gender, race, education, or income. Religiously unaffiliated subjects were younger, less often married, and less often had children. Religiously affiliated subjects reported a more family-oriented social network, reflected in more time spent with first-degree relatives. In contrast, most unaffiliated subjects (74.3%) reported more nonfamilial relationships (friends and others) (t1).
There were no differences between groups in the level of subjective depression (Beck Depression Inventory), objective depression (Hamilton depression scale), hopelessness (Beck Hopelessness Scale), life events (St. Paul-Ramsey Scale), or global functioning (GAS) (t2). Lower general psychopathology scores (BPRS) were found in the patients with no religious affiliation. Significantly higher lifetime scores for aggression (Brown-Goodwin Aggression Inventory) and impulsivity (Barratt Impulsivity Scale) but not hostility (Buss-Durkee Hostility Inventory) were found in the religiously unaffiliated group. Furthermore, a history of substance use disorder was more common in the subjects with no religious affiliation (t2). Subjects with no religious affiliation also reported fewer perceived reasons for living (Reasons for Living Inventory). In particular, scores on three Reasons for Living Inventory subscales: responsibility to family (t=3.1, df=262, p=0.002), child-related concerns (t=2.6, df=253, p=0.008), and moral objections to suicide (t=4.7, df=97.6, p<0.001) were higher in the religiously affiliated group. The scores on other Reasons for Living Inventory subscales did not significantly differ between the two groups: survival and coping beliefs (t=1.83, df=261, p<0.07), fear of suicide (t=0.83, df=261, p<0.41), and fear of social disapproval (t=0.24, df=97, p<0.81).
Relationship Between Religious Affiliation and Suicide Attempts
A backward stepwise logistic regression showed that age (odds ratio=0.97, 95% confidence interval [CI]=0.95 to 0.99; Wald χ2=7.84, p=0.005), but not marital status, parental status, or time spent with family, was significantly associated with suicide attempt status. With regard to clinical variables, only lifetime aggression (odds ratio=1.09, 95% CI=1.03 to 1.14; Wald χ2=9.83, p=0.002) and responsibility to family (odds ratio=0.93, 95% CI=0.91 to 0.97; Wald χ2=17.99, p<0.001) were significantly associated with suicide attempt status, whereas history of past substance use, lifetime impulsivity, general acute psychopathology as rated by the BPRS, and child-related concerns were not.
On the basis of these two data reduction regressions, a final model was tested with suicide attempt status as the outcome variable and age, aggression, responsibility to family, religious affiliation, and moral objections to suicide as the independent variables. Backward stepwise logistic regressions showed that low moral objections to suicide, high lifetime aggression levels, and less feeling of responsibility to family were significantly associated with suicide attempt, whereas religious affiliation per se and age were not (t3). Although the odds ratio for aggression and moral objections to suicide were low (1.09 and 0.90 respectively), the score ranges for these variables indicate a meaningful effect on risk for suicide attempt.
Of note, there was no significant correlation between moral objections to suicide and aggression level (r=–0.08, df=249, p<0.18). Also, when entered in a logistic backward conditional regression model with suicide attempt as a dependent variable, both variables remained significant and independent (moral objections to suicide: odds ratio=0.89, 95% CI=0.85 to 0.93 [[test statistic]=[value], p<0.001]; aggression: odds ratio=1.1, 95% CI=1.06 to 1.1 [[test statistic]=[value], p<0.001]).
Moral objections to suicide mediated the association between religious affiliation and suicide attempt as all three stipulated conditions were met (28). First, religious affiliation was significantly associated with moral objections to suicide. Second, moral objections to suicide was significantly associated with suicide attempt when religious affiliation was statistically controlled. Third, the significant bivariate association between religious affiliation and suicide attempt did not remain significant when moral objections to suicide were controlled statistically (F1).
Relationship Between Religious Affiliation and Suicidal Ideation
Linear stepwise regressions with suicidal ideation as the dependent variable showed that of the demographic variables, age was significant (β=–0.182, t=–2.9, p=0.003), whereas marital status, parental status, and social network were not. Of the clinical variables, linear stepwise regression analysis showed that aggression (β=0.218, t=3.6, p<0.001) and responsibility to family (β=–0.23, t=–3.7, p<0.001) were significant, whereas history of past substance abuse, BPRS score, impulsivity, and child-related concerns were not significant. The final model with suicidal ideation as the outcome variable and age, aggression, responsibility to family, religious affiliation, and moral objections to suicide as the independent variables revealed that high aggression scores, low moral objections to suicide, and younger age were significantly and independently associated with suicidal ideation. Religious affiliation and responsibility to family were not (t4).