A sample of 301 amphetamine users were interviewed about their experiences of psychological symptoms prior to, and subsequent to, their initiation of amphetamine use. Psychological morbidity was common, with 44% scoring greater than a conservative cut-off of 8 on the General Health Questionnaire. The most commonly reported symptoms subsequent to the onset of amphetamine use were depression (79%), anxiety (76%), paranoia (52%), hallucinations (46%) and violent behaviour (44%). All these symptoms increased in prevalence after the onset of amphetamine use. Route and frequency of amphetamine administration were significant independent predictors of overall psychological morbidity, while route of administration was related to the experience of hallucinations, violent behaviour and paranoia. The avoidance of injection as a route of administration and the use of amphetamines less than weekly are recommended as steps that users can take to reduce the psychological sequelae of amphetamine use.