Brain Reward and Anabolic Steroids

Pine Cone and Peacocks from Vatican Museum

Testosterone displays effects on brain function in both males and females.

Emanuela Mhillaj and colleagues recently published a nice summary of what is currently known about the effects of anabolic-androgen steroids (AAS) on the brain.

Their review highlighted the potential for AAS to modulate brain reward function and potentially lead to a drug dependence type of abuse pattern.

Here are some of my notes on their discussion of AAS and the brain reward system:

• Studies of brain reward and AAS use in humans is confounded by perceived user benefits in appearance, strength and athletic performance
• Animal models of AAS and brain reward provide a model free of these confounding effects
• Conditioned place preference (CPP) is a relevant model for reward study in rodents
• Synthetic AAS compounds including nandrolone and drostanolone show rewarding CPP in both male mice and rats
• This effect can be blocked by dopamine antagonists--dopamine pathways are key in reward modulation
• Testosterone brain injections or implants produce reward response behaviors in rodents
• Hamster models show reward behavior with intravenous AAS injection but not oral ingestion
• PET imaging in rodents has shown upregulation of dopamine transporter protein
• The endogenous opioid system may modulate reward and reinforcement mechanisms of AAS
• Beta endorphin levels increase in brain regions of rats treated with AAS
• In humans, AAS use is commonly associated with abuse of other substances including including alcohol, cocaine, opiates, cannabis and ecstasy

This multi-drug abuse pattern in humans with AAS complicates the assessment of AAS effects on dependence and behavior. It is possible that brain reward mechanisms and risk for abuse and dependence vary among humans. Risk for alcohol, drug or nicotine dependence may be a marker for higher AAS abuse risk in humans.

Additionally, in a study that I conducted, antisocial personality traits were increased in humans with illicit AAS use. Antisocial personality is a risk factor for alcohol and drug abuse as well as aggressive behavior.

Readers with more interest in the review article can access the free full-text manuscript by clicking on the PMID link in the citation below.

Photo of peacocks and pine cone is from the author's files.

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Mhillaj E, Morgese MG, Tucci P, Bove M, Schiavone S, & Trabace L (2015). Effects of anabolic-androgens on brain reward function. Frontiers in neuroscience, 9 PMID: 26379484

Yates WR, Perry PJ, & Andersen KH (1990). Illicit anabolic steroid use: a controlled personality study. Acta psychiatrica Scandinavica, 81 (6), 548-50 PMID: 2378247