Objective: This study aims to compare treatment response in bipolar I or II depression and generalized anxiety disorder (GAD) with and without recent alcohol and/or cannabis use disorder (ALC/CAN) to quetiapine-XR (extended release) or placebo.
Methods: A randomized, double-blind, 8-week study of quetiapine-XR versus placebo in patients with bipolar I or II depression and GAD with or without a recent ALC/CAN was used to compare changes in Hamilton Depression Rating Scale-17, Hamilton Anxiety Rating Scale, the 16-item Quick Inventory of Depressive Symptomatology-Self-Report (QIDS-SR-16), Clinical Global Impression for Bipolar Disorder-Severity (CGI-BP-S), and Timeline Follow Back within and between groups.
Results: In the quetiapine-XR group, patients with a recent ALC/CAN (n = 22) had significant decreases in QIDS-SR-16 (-9.6 ± 1.6 vs. -3.7 ± 1.7) and CGI-BP-S (-1.6 ± 0.4 vs. -0.8 ± 0.03) than those without a recent ALC/CAN (n = 24). In the placebo group, both patients with a recent ALC/CAN (n = 23) and those without (n = 21) had similar reductions in these measures. The reduction of QIDS-SR-16 scores in patients with a recent ALC/CAN was also significantly different from that of their counterparts in the placebo group. Patients who received quetiapine-XR had larger decreases in the number of drinking days/week (p = 0.17) and number of cannabis joints/week (p = 0.09) compared to those who received placebo.
Conclusion: Quetiapine-XR was superior to placebo in reducing QIDS-SR-16 total score in patients with a recent ALC/CAN. Patients taking quetiapine-XR used less alcohol and cannabis than patients on placebo, suggesting that quetiapine-XR may be of use in patients with bipolar disorder accompanied by GAD and other comorbidities.
Keywords: Bipolar disorder; Generalized anxiety disorder; Placebo-controlled trial; Quetiapine; Randomized; Substance use disorder.