Response to treatment of detrusor instability in relation to psychoneurotic status. A total of 53 females who entered a double-blind crossover trial of oxybutynin and placebo for idiopathic detrusor instability were questioned about life events and associated medical disorders and were given a psychometric test. Their response to treatment was studied in relation to these factors. It was found that 11% of patients had nocturnal enuresis beyond age 8 and 25% had irritable bowel syndrome: their response to treatment was generally poor. Life events were not consistently related to treatment response. The mean psychoneurotic score of "poor responders" (43.7) was similar to that of female psychoneurotic out-patients (47.7), although one-third of poor responders were normal. Patients who responded well to simple anticholinergic treatment had a mean score (30.7), which was similar to that of normal urban females (33.5). Most good responders and one-third of poor responders showed little evidence of psychoneuroticism: a further search for neurophysiological abnormality in idiopathic detrusor instability is needed. 