Psychological and behavioural changes are associated with anabolic-androgenic steroid (AAS) use. Changes in personality, moods and self-esteem following weight training have also been reported. The fact that nearly all AAS users are also dedicated weight trainers has often been overlooked in studies examining the relationship between AAS use and behavioural change. A triad may exist between AAS use, weight training and behavioural change (including dependence). It is also possible that changes frequently attributed to AAS use may also reflect changes resulting from the concurrent use of other substances such as alcohol, and from dietary manipulation including food supplements. Weight training and related practices should be considered potential confounding factors in future studies designed to examine the psychological and behavioural effects of AAS.