Schizophrenia and epilepsy have long been recognised as more than passing acquaintances. Both involve disrupted brain circuits, both run in families, and both share several treatment overlaps. People with epilepsy are about 2 to 8 times more likely than the general population to develop a psychotic illness, depending on the seizure type and chronicity. People with schizophrenia have higher rates of seizures than the general population, partly because of antipsychotic medication and partly because of underlying neurobiology. Understanding the overlap matters — both for the substantial number of patients who have both conditions and for the rest of us who want to understand schizophrenia better.
Schizophrenia and epilepsy share genetic and neurobiological risk, and patients with both conditions need carefully coordinated care that balances seizure control with antipsychotic side effects and the differential diagnosis of postictal versus primary psychotic symptoms.
Shared mechanisms
Several lines of evidence point to overlap:
- Genetic overlap. Genome-wide association studies have identified shared loci for schizophrenia and epilepsy, particularly in genes affecting glutamate signalling and ion channel function.
- Temporal lobe involvement. The most common epilepsy subtype associated with psychosis is mesial temporal lobe epilepsy. The hippocampus and amygdala — central to temporal lobe epilepsy — are also implicated in schizophrenia.
- Glutamate and GABA dysregulation. Both conditions involve imbalance between excitatory and inhibitory neurotransmission.
- Developmental contributions. Childhood seizures and obstetric complications appear in both histories.
The NINDS epilepsy page and NIMH schizophrenia page are good entry points to the basic neuroscience.
Types of epilepsy-related psychosis
Postictal psychosis
The most common form. Psychotic symptoms emerge within hours to a few days after a seizure or cluster of seizures, last days to weeks, and resolve. Often follows a "lucid interval" of normal mentation between the seizure and the psychosis. Treatment focuses on optimising seizure control and short-term low-dose antipsychotic if needed.
Interictal psychosis
Psychotic symptoms that occur between seizures, often resembling schizophrenia. Sometimes called schizophrenia-like psychosis of epilepsy. May persist chronically and benefit from sustained antipsychotic treatment.
Ictal psychosis
Less common. Psychotic symptoms that are themselves a manifestation of the seizure (most often complex partial status epilepticus). EEG during the episode is the diagnostic key.
Antipsychotics and seizure threshold
Most antipsychotics lower the seizure threshold to some degree, but the magnitude varies:
- Higher seizure risk: Clozapine (clearly highest), chlorpromazine, loxapine
- Moderate: Olanzapine, quetiapine
- Lower: Risperidone, aripiprazole, lurasidone, ziprasidone, haloperidol
The FDA Clozaril label describes the dose-related seizure risk of clozapine. In patients with epilepsy, antipsychotic choice is usually toward the lower-risk options unless there is a compelling reason otherwise.
Anticonvulsants and psychiatry
Several anticonvulsants are used in psychiatry as well:
- Valproate — mood stabiliser, also used in schizoaffective disorder
- Lamotrigine — adjunct in schizoaffective and treatment-resistant cases
- Carbamazepine — historical use in schizoaffective; significant CYP induction limits use
Some anticonvulsants — particularly levetiracetam and topiramate — can themselves cause psychiatric side effects including irritability and, rarely, psychosis. Coordination with the patient's neurologist is essential when switching anticonvulsants in someone with schizophrenia.
What the diagnostic workup should include
For a patient with epilepsy and new psychotic symptoms:
- Detailed seizure history and timing of psychotic symptoms relative to seizures
- EEG, including ambulatory or video-EEG when symptoms are episodic
- Review of anticonvulsant changes and current levels
- Substance use history
- Sleep history (sleep deprivation worsens both seizures and psychosis)
For a patient with schizophrenia and a new seizure:
- Was it a single event or recurrent?
- Is the patient on a higher-seizure-risk antipsychotic, particularly clozapine?
- Are there metabolic contributors — sodium, glucose, alcohol withdrawal?
- Imaging if a focal lesion is suspected
Forced normalisation
An unusual phenomenon worth knowing about: in some patients with epilepsy, achieving complete seizure control is followed by the emergence of psychotic symptoms — and EEG normalises while behavior worsens. The phenomenon, first described by Heinrich Landolt in the 1950s, is rare but real and may require careful adjustment of anticonvulsant dosing rather than simply maximising seizure suppression.
A seizure lasting more than five minutes, repeated seizures without recovery between them, or new psychotic symptoms with confusion or fever require emergency evaluation. Status epilepticus is a medical emergency.
Living with both
Adults living with both epilepsy and a psychotic disorder describe several practical strategies that help:
- One identified provider — often a neurologist or a psychiatrist with neurology training — who oversees both medication regimens
- A medical alert bracelet listing both conditions
- A written list of medications carried at all times
- A seizure diary that also tracks psychiatric symptoms
- Sleep protection — both conditions worsen with sleep deprivation
- Substance use minimisation, particularly alcohol and stimulants
- Driving restrictions clarified in writing with both providers
Resources
See related articles on lamotrigine in schizophrenia, valproate augmentation, and clozapine side effects.
The bottom line
Schizophrenia and epilepsy share neurobiology, sometimes share genes, and frequently share patients. Good care for someone with both conditions starts with one coordinated team, careful attention to medication interactions, and a clear understanding of the differential between postictal, interictal, and primary psychotic symptoms. Done well, both conditions are treatable in parallel.
This article is for educational purposes only and is not medical advice, diagnosis, or treatment. Always consult a qualified mental health professional. If you or someone you know is in crisis, call or text 988 in the US, or your local emergency number.