To ascertain whether benzodiazepines (BZDs) cause behavioural side effects other than those already known or trigger latent mental illness processes, the medical records of 32 patients who had submitted claims for BZD-induced side effects to the Swedish Pharmaceutical Insurance (SPI) claims office during 1985-92 were re-assessed by two psychiatrists on the basis of the DSM-IV system to determine whether a psychiatric syndrome existed before, during, or after the prescription of BZDs. Of the 32 case reports entered into the study, 22 concerned women; mean age at the time of SPI claim submission was 47 years, and the mean duration of BZD treatment was 11.7 years. The BZD dosages were in most cases within recommended therapeutic limits. Twenty-five claimants had also been using other psychotropic drugs. In 28 of the 32 cases a psychiatric syndrome in accordance with DSM-IV was present before the start of BZD treatment-in most cases an anxiety syndrome or anxious personality trait. In the other four cases no diagnosis could be given owing to paucity of information. In the 12 cases of claimants who fulfilled BZD dependence criteria at some point during treatment, withdrawal syndromes might have affected the clinical picture to some extent. Four claimants received additional post-BZD-treatment Axis I diagnoses, but in all four cases the new diagnoses were clearly related to the pre-existing symptom pattern. Thus, apart from the dependence on the drug there was no evidence of psychiatric morbidity caused by the BZDs. The symptoms reported by the claimants as evidence of BZD-induced psychiatric morbidity seem in most cases to have been a feature of pre-existing psychopathology which became more manifest after discontinuation of BZD treatment.