Epilepsy in patients with schizophrenia: Pathophysiology and basic treatments

Schizophrenia is a chronic psychiatric disorder that may lead to epilepsy. However, there are limited findings on the issues. This narrative review aimed to provide a practical perspective on epilepsy in patients with schizophrenia using the current treatment systems for epilepsy. While there has been a debate on the relationship between epilepsy and schizophrenia, i.e., antagonism, affinity, and coincidence, recent large cohort studies have revealed a high frequency of epilepsy in patients with schizophrenia (4-5 times higher than that of general population). The high incidence observed is likely to be due to the bidirectionality between epilepsy and schizophrenia and additional schizophrenia-related conditions, e.g., antipsychotic drugs (APD), substance abuse, and head injury. As for symptomatology of epilepsy, only one small-size study showed that seizures of patients with schizophrenia are equivalent to those of patients without schizophrenia. Patients with schizophrenia exhibit the first seizure in their twenties or later, which are mostly focal seizures. Most of seizures in patients with schizophrenia can be controlled with conventional antiepileptic drugs. Few patients with schizophrenia develop treatment-resistant epilepsy. However, since drug interactions can be more complicated due to multiple conditions, such as pre-existing polypharmacy, heavy smoking, irregular eating, and comorbid metabolic disorders, cautious monitoring for clinical symptoms is required. To improve seizure control and adherence, non-pharmacological approaches are also recommended. Thus far, for seizure treatments in patients with schizophrenia, we have to use many empirical findings or substitute certain findings from population without schizophrenia because evidence is insufficient. The accumulation of clinical findings may contribute to the development of efficient treatment systems.