Changes in inflammation with treatment for bipolar II depression: Pilot trial data on differential effects of psychotherapy and medication

Objectives

Limited prospective data, mostly focused on bipolar I disorder, suggests that pro-inflammatory cytokines are elevated in abnormal mood states. We evaluated whether treatment normalizes peripheral markers of inflammation in bipolar II disorder.

Methods

Using data from a randomized clinical trial of Interpersonal and Social Rhythm Therapy (IPSRT) + quetiapine vs. IPSRT + placebo for bipolar II depression, we examined whether these treatments for bipolar II depression impact inflammatory cytokines and whether observed changes in cytokines are associated with changes in depressive symptomatology as measured by the Hamilton Rating Scale for Depression (HRSD-17).

Results

Cytokine values were available for 33 participants who completed baseline and 20-week follow-up visits. After excluding those with CRP values > = 10 mg/L, there were 27 patients available for analysis (IPSRT + quetiapine N = 10, IPSRT + placebo N = 17). Baseline measure of inflammation did not appear to moderate treatment response, nor was change in HRSD-17 score correlated with changes in cytokines. Those who received IPSRT + quetiapine had significantly greater increases in IL-6 (p = 0.02) and TNF-α (p = 0.04), even after adjusting for changes in body mass index, than the IPSRT alone group. Descriptively, the quetiapine group showed increases in pro-inflammatory and decreases in anti-inflammatory cytokines and the psychotherapy group showed reduced pro-inflammatory cytokines.

Conclusions

Despite both groups showing depression improvement, this small study suggests a more pro-inflammatory cytokine profile over time with quetiapine plus psychotherapy compared to psychotherapy alone. Elevated risk of cardiovascular morbidity and mortality among those with bipolar II disorder underscores the importance of delivering treatments that do not exacerbate these risk factors.