Epilepsy and Psychosis

Psychosis is a significant comorbidity for a subset of patients with epilepsy, and may appear in various contexts. Psychosis may be chronic or episodic. Chronic Interictal Psychosis (CIP) occurs in 2-10% of patients with epilepsy. CIP has been associated most strongly with temporal lobe epilepsy. Episodic psychoses in epilepsy may be classified by their temporal relationship to seizures. Ictal psychosis refers to psychosis that occurs as a symptom of seizure activity, and can be seen in some cases of nonconvulsive status epilepticus. The nature of the psychotic symptoms generally depends on the localization of the seizure activity. Postictal Psychosis (PIP) may occur after a cluster of complex partial or generalized seizures, and typically appears after a lucid interval of up to 72 hours following the immediate postictal state. Interictal psychotic episodes (in which there is no definite temporal relationship with seizures) may be precipitated by the use of certain anticonvulsant drugs, particularly vigabatrin, zonisamide, topiramate, and levetiracetam, and is linked in some cases to “forced normalization” of the EEG or cessation of seizures, a phenomenon known as alternate psychosis. Seizures and psychosis may also co-occur secondary to another neurologic disorder, such as a traumatic brain injury, brain tumor, or limbic encephalitis. When a patient with epilepsy develops psychosis, the clinician should attempt to determine the cause, as treatment approach may vary. In this article, we review the various forms of epilepsy-related psychosis and discuss a rational approach to the evaluation and management of patients with epilepsy and psychosis.