The condition of men having low testosterone with long-term pain medication (opioid) usage is called opioid-induced androgen deficiency (OPIAD). Low testosterone can be caused by pain medication effects on part of the brain (hypothalamic-pituitary axis) which ultimately result in decreased testosterone production by the testes. Typical symptoms of low testosterone (hypogonadism) may include decreased muscle mass, increased fat, osteoporosis, anemia, erectile dysfunction, delayed ejaculation. In addition, men with low testosterone may experience decreased attention, and decreased libido, fatigue, and depressed mood. Few studies have looked at hormonal changes caused by long-term opioid usage in men.