The study of discrete organic cerebral lesions resulting in clearly definable psychiatric disorders may provide an understanding of the underlying pathophysiological basis of these disorders. However, the relation between lesion location and psychiatric illness after stroke remains unclear. Fifty five patients referred to hospital were identified who had a single lesion on CT which was consistent with their neurological presentation and who did not have evidence of a persistent affective disorder at the time of the stroke. Six months after stroke standardised psychiatric assessment disclosed that 26% of the patients met DSM-IV criteria for an anxiety or depressive disorder, with depression the most common diagnosis (20%). Pathological emotionalism was diagnosed in 18% of patients, particularly those who were depressed (p<0.0001). Depression was significantly associated with larger lesions involving the right cerebral hemisphere (p=0.01). The importance of depression as a consequence of stroke has been clarified by the studies in this area. However, wide confidence intervals support the possibility that significant results may be due to chance. A systematic review of these studies is now needed if a consensus is to be reached.