The average rate of people affected has been estimated to be around 30% for individuals taking antipsychotic medication, such as that used to treat schizophrenia. A study being conducted at the Yale University School of Medicine has estimated that "32% of people develop persistent tics after 5 years on major tranquilizers, 57% by 15 years, and 68% by 25 years." More drastic data was found during a longitudinal study conducted on individuals 45 years of age and older who were taking antipsychotic drugs. According to this research study, 26% of people developed tardive dyskinesia after just one year on the medication. Another 60% of this at-risk group developed the disorder after 3 years, and 23% developed severe cases of tardive dyskinesia within 3 years. According to these estimates, the majority of people will eventually develop the disorder if they remain on the drugs long enough.Elderly people are more prone to develop tardive dyskinesia, and elderly women are more at-risk than elderly men. The risk is much lower for younger men and women, and also more equal across the sexes. People who have undergone electroconvulsive therapy or have a history of diabetes or heavy alcohol use also have a higher risk of developing tardive dyskinesia.Several studies have recently been conducted comparing the number of people affected of tardive dyskinesia with second generation, or more modern, antipsychotic drugs to that of first generation drugs. The newer antipsychotics appear to have a substantially reduced potential for causing tardive dyskinesia.
Conversion disorder (CD), or functional neurologic symptom disorder, is a diagnostic category used in some psychiatric classification systems. It is sometimes applied to patients who present with neurological symptoms, such as numbness, blindness, paralysis, or fits, which are not consistent with a well-established organic cause, which cause significant distress, and can be traced back to a psychological trigger. It is thought that these symptoms arise in response to stressful situations affecting a patients mental health or an ongoing mental health condition such as depression. Conversion disorder was retained in DSM-5, but given the subtitle functional neurological symptom disorder. The new criteria cover the same range of symptoms, but remove the requirements for a psychological stressor to be present and for feigning to be disproved. ICD-10 classifies conversion disorder as a dissociative disorder while DSM-IV classifies it as a somatoform disorder. Signs and symptoms
Conversion disorder begins with some stressor, trauma, or psychological distress. Usually the physical symptoms of the syndrome affect the senses or movement. Common symptoms include blindness, partial or total paralysis, inability to speak, deafness, numbness, difficulty swallowing, incontinence, balance problems, seizures, tremors, and difficulty walking. The symptom of feeling unable to breathe, but where the lips are not turning blue, can indicate conversion disorder or sleep paralysis. Sleep paralysis and narcolepsy can be ruled out with sleep tests. These symptoms are attributed to conversion disorder when a medical explanation for the conditions cannot be found. Symptoms of conversion disorder usually occur suddenly.