Mirtazapine-induced Mania and the Role of Interpersonal and Social Rhythm Therapy: Case Report and Literature Review

Abstract Antidepressants can cause manic or hypomanic switches and provide a valuable window into understanding the heuristics of mood disorders. However, mirtazapine-induced switches are rare, with only anecdotal reports available. This report describes a gentleman in his sixties with no prior psychiatric history who experienced consecutive personal losses and was initially diagnosed with major depressive disorder. He was prescribed mirtazapine, which precipitated an episode characterized by a pathologically cheerful mood, increased rate of speech, affective irritability, and significant interpersonal disturbances. He was re-diagnosed with a manic episode; mirtazapine was ceased, and he was treated with olanzapine. Hypothesizing the interpersonal role transition as the major precipitator of the affective instability, a tailored interpersonal and social rhythm therapy (IPSRT) module was designed and applied alongside in this context. IPSRT focused on stabilizing disrupted social rhythms, addressing role transitions, and processing grief, resulting in significant mood stabilization, and prevention of further relapses. This report highlights the importance of the social zeitgeber hypothesis in understanding mood instability, especially if the precipitating factors are of a social nature. It underlines the need for understanding and conceptualizing psychiatric symptoms within the contexts in which they evolve, and the need for close monitoring of atypical symptoms in the treatment of bipolar disorders.