Despite demonstrated relationships between activity and clinical change, we lack effective measures of time use in psychosis. Existing time budget measures of activity are demanding to complete, and thus unsuited to routine clinical use as measures of change. Less burdensome 'check-box' measures are prone to bias and omission in the activities selected. We recently devised a simplified time budget measure of activity in psychosis which was piloted on a small sample [Jolly, S., Garety, P., Dunn, G., White, J., Aitken, M., Challocombe, F., Griggs, M., Wallace, M., Craig, T. 2005. A pilot validation study of a new measure of activity in psychosis. Soc. Psychiatry Psychiatr. Epidemiol. 40, 905-911]. This study is a larger scale validation. 276 participants with a recent relapse of non-affective psychosis completed the new time budget, together with an established measure of global social functioning, measures of positive and negative psychotic symptoms, positive symptom distress and affect. The time budget measure showed a correlation of 0.5 with both the SOFAS and the SANS avolition/apathy subscale. Activity levels were related to psychotic symptomatology, both positive and negative. Positive symptom distress was more strongly associated with activity levels than symptom severity and affective disturbance. We conclude that the time budget measure can be used as an indicator of social functioning, with potential as a measure of therapeutic change. We are currently investigating its sensitivity in this context.