A psychotropic drug monitoring study in general practice was carried out in 1983 and 1984 using a computerized drug information system. The prescription data analysed in the study came from 68 general practitioners operating in south Verona and have been collected by 14 community pharmacies located in the same area. Benzodlazeplne hypnotics were the most commonly prescribed drugs, followed by antidepressants and neuroleptics both in 1983 and in 1984. The distribution of the general practitioners in terms of low, medium and high prescribers was examined by analysing the rates of prescriptions per registered patient. The rates were obtained for the total number of prescriptions and also for each of the three different classes of psychotropic drug. The proportion of low and high prescribers decreased from 1983 to 1984 (18.3 versus 11.7 and 26.7 versus 16.7 for low and high prescribers respectively); this change was mainly due to the reduction in benzodiazepine prescriptions. No significant correlation was found between the rates of psychotropic drug prescriptions and list size. The monthly variation in prescription of the three drug classes followed a similar pattern during the two years; the fluctuations were clearly cyclical, more definitely in 1984 than in 1983 where the most relevant feature was the summer trough.