Epileptic psychosis is one of the most common causes of psychotic disorder due to another medical condition. Psychotic symptoms can arise during seizures (ictal psychosis), following seizures (postictal psychosis), or at a time not related to seizures (interictal psychosis). The prevalence of epileptic psychosis has been reported to be between two and ten percent of those with epilepsy, and is one of the most dangerous outcomes of the disorder. Of the three periods during which psychotic symptoms may occur, postictal psychosis is the most frequent.
Postictal psychosis typically occurs in the days immediately following a seizure but can occur up to a week out. Research has suggested that postictal psychosis is more prevalent in those with seizure foci on both sides of the brain. There are often warning signs before postictal psychosis, with insomnia, restlessness, and irritability being most common. Symptoms of postictal psychosis generally dissipate rapidly when treated with medication such as antipsychotics and benzodiazepines. Postictal psychosis is common enough that some doctors administer low doses of antipsychotic medication prophylactically after a seizure. Postictal psychosis is most commonly seen in people with a long history of drug-resistant seizures. According to research, between 10 and 25 percent of people who experience repeated postictal psychosis will eventually develop interictal psychosis.
Ictal psychosis, a psychotic episode that occurs concurrently with a seizure, is more rare. It typically presents with unresponsiveness and automatic body movements.
Interictal psychosis can occur at any time for people with epilepsy. Data suggests that interictal psychosis is not the result of normal epileptic pathology. The occurrence of interictal psychosis may indicate widespread abnormalities in the brain, or a brain tumor. Typically, interictal psychosis begins only after several years of epileptic seizures. Interictal psychosis is likely to be a chronic condition and should be treated with antipsychotic medication. Some evidence suggests that anti-epileptic drugs may induce psychotic symptoms in patients with interictal psychosis.