The neurobiology and addiction potential of anabolic androgenic steroids and the effects of growth hormone.

Anabolic androgenic steroids (AAS) are substances that mimic the hormone testosterone, and primarily act via the androgen receptor. In addition to their physiological effect on muscle tissue and growth, research from the last decade has shown that AAS have a pronounced impact on the central nervous system. A large number of studies have demonstrated that AAS affect the mesolimbic reward system in the brain. However, whether the direct effects of AAS on endorphins, dopamine, serotonin and GABA etc. and on the corresponding and related systems lead to dependence needs to be further elucidated. According to recent studies, the prevalence of AAS dependence among AAS users has been estimated to be approximately 30%, and polysubstance use, of both pharmaceutical drugs and narcotics, within this group is common. The present review primarily discusses AAS in the context of addiction and dependence, and further addresses the issue of using multiple substances, i.e. stimulants and opiates in combination with AAS. In addition, aspects of the treatment of AAS dependence, the connection between AAS abuse and cognition, and AAS-induced neurotoxicity are presented. Currently, performance enhancing drugs are frequently used in combination with AAS. Therefore, a large section on growth hormone and insulin-like growth factor is also included.