Purpose: To clarify duration of postictal psychosis (PIP) episodes and identify factors that influence its duration.
Methods: Fifty-eight patients with epilepsy exhibited 151 PIP episodes during a mean follow-up period of 12.8 years. Distribution of the duration of these episodes was determined, and factors potentially affecting were analyzed. Factors analyzed included PIP-related variables (i.e., antecedent seizures and the lucid interval) and patient characteristics (i.e., type of epilepsy, lateralization of EEG abnormalities, and intellectual functioning).
Results: The mean duration of the 58 first PIP episodes was 10.5 days, and that of all 151 PIP episodes (including multiple episodes) was 9.2 days. Approximately 95% of the PIP episodes resolved within 1 month. Most PIP-related variables, except for antipsychotic drugs administered, were not associated with duration of the episodes. Several patient characteristics, i.e., history of interictal psychosis, family history of psychosis, and intellectual functioning, were associated with duration of the PIP episodes.
Conclusions: This study showed that most PIP episodes last less than 1 month. PIP episodes appear to be prolonged when individuals have an underlying vulnerability to psychosis. Clinical phenomena that can trigger PIP may not determine the course of the PIP episode.