In a practice of 6000 patients, all long term users of day time benzodiazepine tranquillizers were identified and matched for age and sex with controls. Patients and controls were asked to complete two postal questionnaires, one to measure a number of neurotic personality traits and the other to record details of personal history thought to be relevant. Tranquillizer users were also sent a third questionnaire which surveyed their attitudes to reliance on tranquillizers. Long term users of benzodiazepines had significantly higher scores for anxiety and other neurotic traits but their personal histories showed few significant differences from those of controls. Patients reliant on benzodiazepines seem to be a distinct, more ;neurotic' sub-group of the practice population although their lives have not been any more disturbed. Most patients thought that tranquillizers had helped them but many felt uneasy about being reliant on them. Follow up showed a trend towards spontaneous discontinuing of the tablets.