The antipsychotic drug Risperdal has been associated with numerous side effects, including involuntary movements, growth of abnormally large breasts in males, and neuroleptic malignant syndrome (NMS).

Approved for use in children in 2006, Risperdal, or risperidone, is used to treat mania, autism, bipolar disorder, irritability, aggression, schizophrenia and other behavior disorders.

Neuroleptic malignant syndrome (NMS) is the most Risperdal serious side effect and is characterized by muscle rigidity, fever, autonomic instability, and cognitive changes such as delirium.

According to the National Institutes of Health, NMS typically develops within a couple weeks of taking an antipsychotic, but may develop at any time. Intensive care is generally needed once someone is diagnosed with NMS. A muscle relaxant may be prescribed and the fever is treated aggressively.

Another side effect, tardive dyskinesia, may include facial grimacing, finger movement, jaw swinging, repetitive chewing and tongue thrusting. Tardive dyskinesia – which means delayed abnormal movement – mostly affects the lower face. While it most often strikes those who have taken neuroleptic medications for months or years, it has been reported to affect some patients in as few as six weeks.

Risperdal’s side effects have spawned hundreds of lawsuits against Johnson & Johnson and Janssen Pharmaceuticals alleging pain and suffering resulting from gynecomastia, commonly referred to as “man boobs.”

The Risperdal lawsuits accuse the manufacturer of failing to adequately warn boys prescribed the medication that breast development was a possible side effect and that surgery might be needed to have the breasts removed.

Symptoms of gynecomastia include male breast growth, painful breasts and nipple pain or nipple discharge.

Johnson & Johnson reached a confidential settlement for a Risperdal lawsuit in 2012 brought by a 21-year-old man who said that growing breasts resulted in “severe psychological trauma.”

The plaintiff underwent a mastectomy to remove the breasts. Shortly after the first settlement, Johnson & Johnson settled cases brought on behalf of at least five other boys who experienced similar breast development.

The mental anguish of being bullied and teased results in depression, anxiety and insecurity in young men already battling mental health issues, according to the Risperdal lawsuits.

The medical journal Plastic and Reconstructive Surgery has reported that research shows that even mild breast growth can have a serious, negative psychological impact on boys.

Male breast growth is gradual often beginning with nipple tenderness. The condition can affect one or both breasts. In some cases of gynecomastia, males produce breast milk.