Anabolic-androgenic steroid use may have a wide range of adverse psychiatric and behavioural effects. The available data, however, are often inconsistent and inconclusive concerning possible effects of anabolic-androgenic steroids on libido in men, in women and also the way in which they affect libido differently in males and females. Anabolic-androgenic steroids may both relieve and cause depression. Cessation or diminished use of anabolic-androgenic steroids may also result in depression. More study is required to determine whether or not the disparate data on depression are consistent clinical observations. The level of testosterone appears to be positively associated with "aggression", particularly in response to provocation. Various psychotic symptoms and manic episodes may be associated with anabolic-androgenic steroids. The possibility of hypomania induced by synthetic androgens must also be considered.