OBJECTIVE--To estimate the prevalence of emotionalism after stroke, to assess its relation with other mood disorders, and to identify clinical variables with which it is associated. DESIGN--Descriptive study of a cohort of patients consecutively entered on a community stroke register. SETTING--Community based research project. PATIENTS--A total of 128 patients who had suffered first ever stroke. INTERVENTIONS AND END POINTS--Patients were interviewed by a psychiatrist at 1, 6, and 12 months after stroke. Mood state was assessed by standardised semistructured interview (present state examination) and self report (Beck depression inventory). Intellectual impairment was assessed by mini mental state examination and Frenchay aphasia screening test. In addition, stroke lesions were localised by computed tomography. MAIN RESULTS--Emotionalism was reported by 13 of 89 patients (15%) at one month, 25 of 119 (21%) at six months, and 12 of 112 (11%) at 12 months after stroke. Patients with emotionalism had higher scores on both measures of mood disorder (at 6 months: mean Beck score 10.5 v 6.4; present state examination score 7.2 v 5.1) and more diagnosable psychiatric disorder (at 6 months: 40% v 14%; odds ratio 4.2, 95% confidence interval 1.5 to 11.9). Almost all episodes were provoked by clearly identified and appropriate emotional experiences. Patients with emotionalism also had more intellectual impairment and larger lesions on computed tomography. Lesions in the left frontal and temporal regions were particularly associated with emotionalism: at 6 months 8 of 14 patients (57%) with such lesions had emotionalism compared with 10 of 52 (19%) of those with lesions elsewhere (odds ratio 5.6, 95% confidence interval 1.4 to 22). CONCLUSIONS--Emotionalism is common after stroke. It is neither emotionally meaningless and inappropriate, nor is it found mostly in patients with bilateral brain damage. Emotionalism is associated with symptoms of a more general mood disturbance and is found especially in patients with left frontal and temporal lesions.