A new study reveals that Anabolic-androgenic steroids (AAS ) can have deleterious effects on the brain, causing it to age prematurely. AAS, a synthetic version of the male sex hormone testosterone, are sometimes used as a medical treatment for hormone imbalance.

The report appears in Biological Psychiatry titled Cognitive Neuroscience and Neuroimaging, published by Elsevier.

"Anabolic steroid use has been associated with a range of medical and psychological side effects," said lead author, Astrid Bjornebekk, PhD, Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway. "However, since anabolic steroids have only been in the public domain for about 35 years, we are still in the early phase of appreciating the full scope of effects after prolonged use. The least studied effects are those that relate to the brain."

Steroid hormones readily enter the brain, and receptors for sex hormones are found throughout the brain. Because AAS are administered at much higher doses than those naturally found in the body, they could have a harmful impact on the brain, particularly over a long period of use. Previous studies have shown that AAS users performed worse on cognitive tests than non-users.

Dr Bjornebekk and colleagues performed magnetic resonance imaging (MRI) of the brains of 130 male weightlifters with a history of prolonged AAS use and of 99 weightlifters who had never used AAS. Using a set of data compiled from nearly 2,000 healthy males from age 18 to 92 years of age. The researchers used machine learning to determine the predicted brain age of each of their participants and then determined the brain age gap: the difference between each participant's chronological age and their predicted brain age. Advanced brain age is associated with impaired cognitive performance and increased risk for neurodegenerative diseases.