The potential for antimicrobials to adversely affect mental state.

This is a case report highlighting the influence that antimicrobials (clarithromycin in particular) can have on one's mental state. We discuss the case of a middle-aged woman who presented to an acute admissions unit under Irish Mental Health Act for involuntary admission because of concerns expressed by her family and general practitioner regarding a recent change in behaviour and onset of irritable mood. This lady was diagnosed with an episode of mania that was thought to be precipitated by a combination of psychosocial stressors, recent discontinuation of psychotropic medication and complicated by a recent course of clarithromycin.