In contrast to depressive symptoms, pre-ictal and ictal psychotic symptoms are rare. Ictal psychotic episodes can be the clinical expression of nonconvulsive recurrent seizure activity known as status epilepticus of simple partial, complex partial, or absence seizures. In the case of simple partial status, the diagnosis may often be difficult because scalp recordings may not detect any changes in ictal EEG patterns.

Postictal psychotic symptoms were reported by 7 out of 100 consecutive patients with intractable partial epilepsy in one study. These symptoms were also associated with symptoms of depression, anxiety, and disturbances in sleep and appetite. The duration of these symptoms ranged from 2 to 24 hours.

Psychotic symptoms may cluster and form postictal psychotic episodes, which may occur in 6% to 10% of patients with intractable epilepsy. More often than not, the presence of postictal psychotic episodes is suggestive of more than one seizure focus. Postictal psychotic episodes may last from several hours to several weeks. They usually remit with low doses of antipsychotic medication.

Typically, episodes of postictal psychosis occur in patients who have had epilepsy for at least 10 to 15 years. The episodes tend to follow the occurrence of clusters of generalized tonic-clonic seizures and may appear after a symptom-free lag-time of 12 to 120 hours. Usually, the first symptom is insomnia. If these episodes tend to recur after a cluster of seizures in a particular patient, family members are taught to identify the insomnia and administer antipsychotic medication at low doses, which may abort the psychotic episode. Given the episodic nature of these symptoms and rapid remission after low doses of antipsychotic medication, patients with postictal psychosis should not be prescribed continuous antipsychotic medication.

Recent studies have shown that some patients who experience recurrent postictal psychotic episodes can go on to develop interictal psychotic disorders. In those patients, long-term therapy with antipsychotic drugs may be necessary.

Among the most frequent symptoms of postictal psychosis are:

  • thought blocking (a sudden interruption in thought) and overt thought disorder, manifested by an inability to express thoughts in a coherent manner
  • illusions and formed and unformed hallucinations in different modalities (visual, auditory, olfactory, etc.)
  • paranoid, religious, and grandiose delusions
  • acute confusion

Interictal psychosis can develop as a schizophrenia-like state or be associated with an affective disorder. The schizophrenia-like psychosis of epilepsy, which is believed to affect between 2% and 8% of patients with long-standing complex partial seizures, has been associated primarily with temporal lobe epilepsy (TLE). Although this type of psychiatric presentation may appear similar to idiopathic schizophrenia, important distinctions can be made. Compared to idiopathic schizophrenia, schizophrenia-like states in epilepsy include:

  • an intact affect
  • unimpaired ability to relate to others
  • relative absence of negative symptoms (i.e., flat affect, lack of initiative)
  • rare deterioration of the patients' personality
  • absence of psychosis in the patient's family
  • absence of premorbid schizoid traits and better premorbid day-to-day function
  • psychosis marked by ideas of reference, paranoid delusions, and hallucinations

Psychosis may be the expression of adverse effects of AEDs. The discontinuation of an AED with mood stabilizing properties can also trigger a manic or psychotic depression in patients with an underlying mood disorder that had been controlled with that AED.

Other causes of psychosis include substance use and withdrawal and primary psychiatric conditions such as brief reactive psychosis.

The treatment approach to psychosis in epilepsy depends on the etiology of the symptoms and whether the psychosis is the sustained interictal type. Symptoms limited to the postictal period may remit spontaneously, although antipsychotic medication at low doses is often required. A schizophrenia-like syndrome during the interictal period requires antipsychotic medications.

Adapted from: Holzer JC and Bear DM. Psychiatric considerations in patients with epilepsy. In: Schachter SC, Schomer DL, eds. The comprehensive evaluation and treatment of epilepsy. San Diego, CA: Academic Press; 1997. p. 131-148.
With permission from Elsevier (www.elsevier.com)

Authored by: Jacob C. Holzer MD | David M. Bear MD
Reviewed by: Andres M. Kanner MD on 4/2004