AbstractClinical characteristics predicting response and remission to psychopharmacological treatment of bipolar disorder (BD) and co-occurring anxiety disorders have been understudied. We hypothesized that non-response to risperidone or placebo in individuals with co-occurring BD and anxiety symptoms would be associated with a more severe clinical course of BD, and certain demographic variables. This study was a secondary analysis of a randomized, double-blind, parallel, 8-week study comparing risperidone monotherapy and placebo in individuals with BD plus current panic disorder, current generalized anxiety disorder (GAD), or lifetime panic disorder (n = 111) [31]. We compared clinical characteristics of responders (50% improvement on the Hamilton Anxiety Scale [HAM-A]) and non-responders as well as remitters (HAM-A < 7) and non-remitters in risperidone treatment (n = 54) and placebo (n = 57) groups. For non-responders in the risperidone group, co-occurring lifetime panic disorder was significantly more common than for non-responders in the placebo group. Apart from this, no significant differences in course of illness or demographics were found either between or across groups for patients with BD and co-occurring anxiety symptoms receiving risperidone or placebo in this acute phase study.