This information pertains only to the older neuroleptics. TD occurs late in the neuroleptic treatment. It may take 2 years or more for TD to develop. However, elderly who are on neuroleptics, usually much shorter. The exact mechanism how neuroleptics cause TD remains unclear.
Women have a higher risk than men.
Diabetics on neuroleptics have higher risk than nondiabetics on neuroleptics. In severe cases, swallowing and breathing functions may be affected which can lead to irregular breathing, belching, grunting noises and even choking. In some cases, even sexual performance is affected. It was originally believed that TD is always irreversible. However, there have been case reports of decreasing symptoms of TD even with continued use of neuroleptics.