Prevalence and distinct correlates of anxiety, substance, and combined comorbidity in a multi-site public sector sample with bipolar disorder.

Background: Recent data indicate high prevalence of both anxiety and substance comorbidity in bipolar disorder. However, few studies have utilized public sector samples, and only one has attempted to separate contributions of each type of comorbidity.

Methods: 328 inpatient veterans with bipolar disorder across 11 sites were assessed using selected Structured Clinical Interview for DSM-IV modules and self-reports.

Results: Comorbidity was common (current: 57.3%; lifetime: 78.4%), with multiple current comorbidities in 29.8%. Substance comorbidity rate was comparable to rates typically reported in non-veteran inpatient samples (33.8% current, 72.3% lifetime). Selected anxiety comorbidity rates exceeded those in other inpatient samples and appeared more chronic than episodic/recurrent (38.3% current, 43.3% lifetime). 49% of PTSD was due to non-combat stressors. Major correlates of current substance comorbidity alone were younger age, worse marital status, and higher current employability. Correlates of current anxiety comorbidity alone were early age of onset, greater number of prior-year depressive episodes, higher rates of disability pension receipt, and lower self-reported mental and physical function. Combined comorbidity resembled anxiety comorbidity.

Limitations: This is a cross-sectional analysis of acutely hospitalized veterans.

Conclusions: Distinct patterns of substance and anxiety comorbidity are striking, and may be subserved by distinct neurobiologic mechanisms. The prevalence, chronicity and functional impact of anxiety disorders indicate the need for improved recognition and treatment of this other dual diagnosis group is warranted. Clinical and research interventions should recognize these divergent comorbidity patterns and provide individualized treatment built "from the patient out."