Differences in depression symptom endorsement between bipolar disorder and major depressive disorder: lessons learned from the National Epidemiologic Survey on Alcohol and Related Conditions

Differential endorsement of suicidal ideation and attempt in bipolar versus unipolar depression: a testlet response theory analysis

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.

Adjunctive Behavioral Activation for the Treatment of Bipolar Depression: A Proof of Concept Trial

BACKGROUND

Grounded in a model focused on exposure to response-contingent positive reinforcement, and with evidence supporting its acute treatment effects for unipolar depression, an adjunctive behavioral activation (BA) intervention may be especially well suited to the treatment of bipolar depression. The goal of this study was to modify BA for the adjunctive treatment of bipolar depression and to pilot it in a proof of concept trial to assess its preliminary feasibility and acceptability for this population.

METHODS

Twelve adults with bipolar depression were recruited from hospital settings and enrolled in a 20-week open trial of the modified BA, delivered in 16 outpatient sessions, as an adjunct to community pharmacotherapy for bipolar disorder. Symptom severity was assessed at pretreatment and posttreatment by an independent evaluator. Patient satisfaction was also assessed posttreatment.

RESULTS

Feasibility and acceptability were high, with 10 of 12 patients completing treatment, an average of 14.8 (SD=5.2) of 16 sessions attended, and high levels of self-reported treatment satisfaction. Patients exhibited statistically significant improvement from pretreatment to posttreatment on measures of depressive symptoms, manic symptoms, and severity of suicidal ideation.

CONCLUSIONS

Although preliminary and requiring replication in a larger sample, these study data suggest that a modified BA intervention may offer promise as an adjunctive approach for the acute treatment of bipolar depression. Future studies that use more rigorous randomized controlled designs and that directly assess potential mechanisms of action are recommended.