This study identified acute and chronic akathisia in acute psychiatric inpatients receiving conventional antipsychotic medication, and evaluated the clinical characteristics, risk factors and clinical implications of the condition. Akathisia and other movement disorders were systematically assessed in patients consecutively admitted to an acute psychiatric ward over one year. Akathisia was diagnosed in 15 (21%) of 72 patients. Akathisia, developing as an acute condition in seven patients, generally presented with the subjective experience of dysphoria and unease without restless movements. This acute akathisia developed during the first few days of hospitalization and was associated with both a higher average dose of antipsychotic medication and a greater increase in dosage. In the remaining eight cases, akathisia was already present on admission, and thus classified as chronic. Those patients with chronic akathisia exhibited both subjective restlessness and the characteristic restless movements. Chronic akathisia was unrelated to antipsychotic dosage. The proportion of patients with akathisia who discontinued drug treatment was significantly higher than that for patients without the condition. Patients with acute akathisia tended to drop-out of treatment and those with the chronic form tended to have treatment withdrawn by the prescribing clinician. One interpretation is that the subjective distress of acute akathisia may be particularly difficult for patients to tolerate and leads them to stop medication, while patients with more chronic akathisia may have become more accepting of the experience. Repetitive movements of the legs were observed more commonly in those with chronic rather than acute akathisia, and may represent a way of achieving some limited respite.