My 14yr old son has grown large female breasts after using "risperdal" for 1year! is this possible & how?

Gynecomastia: Risperdal can have endocrine side effects. Hyperprolactinemia in some patients may cause sexual dysfunction (i.e., decreased libido, impaired performance), gynecomastia, reduced fertility, galactorrhea, menstrual irregularities (i.e., amenorrhea, oligomenorrhea), and osteoporosis. In addition, as many as one-third of human breast cancers may be prolactin-dependent in vitro. Treatment of risperidon.

Combination of thing: A 14 yo boy, who is likely in mid-puberty, can be expected to have breast development. Compound this with weight gain from risperdol and you get more breast tissue. I agree that if they're very large it's probably a good idea to have a hormone evaluation, but weight control is inherent to making this better if hormones are ok. Some boys end up needing surgery after puberty to get rid of breast.

Side effects: Risperdal and other antipsychotics can cause breast enlargement even in men and boys by causing an increase in the hormone prolactin. Switching to a different medication may be needed. Please consult with your psychiatrist soon.