Background

Published data concerning differences in suicide risk across the mood disorders spectrum remain mixed. The current study used testlet response theory methods to evaluate differences in the endorsement of suicidal ideation and attempt in an epidemiological sample of individuals with bipolar and unipolar depression.

Method

Participants with lifetime history of bipolar I (n=1154), bipolar II (n=494), and unipolar (n=5695) depression were drawn from the National Epidemiologic Survey on Alcohol and Related Conditions, which included 4 structured queries concerning suicidal ideation/attempt. We estimated differential item functioning between groups with a 2-pl parametric item response model.

Results

Endorsement of suicide items increased as a function of underlying depression severity. Equating for severity, endorsement of suicidal ideation and attempt was generally more frequent in bipolar versus unipolar depression, and in bipolar I versus bipolar II depression. Yet findings were not consistent across all suicide items, and differences were small in magnitude.

Limitations

The NESARC relied upon lifetime endorsement of suicide items, and suicide risk was only evaluated within the context of a major depressive episode. Thus, this study could not evaluate endorsement of suicide items within the context of (hypo)manic or mixed states.

Conclusion

Although there were some group differences, patterns of item endorsement were more similar than different. These data support a transdiagnostic model of suicide that emphasizes underlying depression severity over mood disorder class.

Although the important roles of postquit affect and withdrawal symptoms in the process of smoking cessation have been well established, little is known about the relations between prequit affective trajectories and cessation outcome on the target quit date (TQD). This study examined whether a 16-week course of fluoxetine initiated 8 weeks prequit ("sequential" fluoxetine) improved TQD abstinence relative to placebo through its effects on prequit depressive symptoms, affect (withdrawal-relevant negative affect, general negative affect, and positive affect), and craving to smoke among 206 smokers with elevated depressed symptoms. The moderating effects of gender were also examined. In total, 83 smokers (40%) failed to achieve abstinence on TQD, with no difference between treatment conditions or gender. Overall structural equation models showed that fluoxetine had significant indirect effects on TQD abstinence through changes in prequit withdrawal-relevant negative affect and craving, but not depressive symptoms. However, multigroup analyses revealed gender differences. Sequential fluoxetine reduced prequit depressive symptoms, withdrawal-relevant negative affect, and craving only among women. Reduction in prequit depressive symptoms and craving among women, and withdrawal-relevant negative affect among men was associated with TQD abstinence. Moreover, exploratory analysis showed negative trend-level indirect effects of fluoxetine on TQD abstinence via increased side effects, regardless of gender. This study demonstrated the importance of considering gender when examining treatment efficacy. Identifying ways to further reduce prequit depressive symptoms and craving for women and withdrawal-relevant negative affect for men whereas alleviating side effects may help smokers with elevated depressed symptoms achieve the first smoking cessation milestone.