Steroids can have long-lasting and sometimes irreversible side effects on the body. Anabolic steroids have been linked to increased cholesterol, stroke and blood clots, urinary and bowel problems, and problems with the musculoskeletal system. Since steroids are a hormone, much like testosterone, the effects on sex characteristics can be far reaching, causing a kind of hyper-masculinity in young men. They can also cause male-pattern baldness and shrinking of the testicles. The excess of testosterone can also have feminizing effects on young men, such as breast development. (Jerry Adler, 2004)
Pope and his colleagues discovered that those participants who were long-term AAS users did significantly worse than nonusers on a test called "Pattern Recognition Memory," where participants are asked to try to remember a collection of patterns that they have been presented on a computer screen. The scores on this test declined noticeably with increasing lifetime AAS dose. These results remained stable in sensitivity analyses addressing potential confounding factors, indicating that the findings were unlikely to be attributable to some factor other than AAS use.