Antiepileptic drug treatment can induce
psychosis in some patients. However, there are no agreed definitions or diagnostic criteria for
antiepileptic drug-induced
psychotic disorder in the classification systems of either epileptology or psychiatry. In this study we investigated the clinical spectrum of
antiepileptic drug-induced
psychotic disorder in patients with
epilepsy. The medical records of all patients with
epilepsy who were diagnosed by a neuropsychiatrist as having a
psychotic disorder at the Royal Melbourne Hospital from January 1993 to June 2015 were reviewed. Data were extracted regarding
epilepsy and its treatment, psychotic symptoms profile and outcome. The diagnosis of
epilepsy was established in accordance to the classification system of the International League Against
Epilepsy while that of
psychotic disorder was made according to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition and the proposal on neuropsychiatric disorders in
epilepsy. Patients with
antiepileptic drug-induced
psychotic disorder were compared to those with
psychotic disorders unrelated to
antiepileptic drugs assessed over the same period (non-
antiepileptic drug induced
psychotic disorder group). Univariate comparisons were performed and variables with a value of P < 0.1 were selected for the multivariate logistic regression analysis. The records of 2630 in-patients and outpatients with
epilepsy were screened, from which 98 (3.7%) with
psychotic disorders were identified. Among these, 14 (14.3%) were diagnosed to have
antiepileptic drug-induced
psychotic disorder. Excluding one patient who developed
psychosis after
valproate withdrawal, 76.9% in the
antiepileptic drug induced
psychotic disorder group were female and the percentage of temporal lobe involvement was higher in the
antiepileptic drug induced
psychotic disorder group (69.2% versus 38.1%, P < 0.05). Current use of
levetiracetam was higher in
antiepileptic drug-induced
psychotic disorder group (84.6% versus 20.2%, P < 0.01) while use of
carbamazepine was higher in the comparator group (15.4% versus 44.0%, P < 0.05). Multivariate logistic regression confirmed four factors associated with
antiepileptic drug-induced
psychotic disorder: female gender, temporal lobe involvement and use of
levetiracetam, and a negative association with
carbamazepine. Disorganized behaviours and thinking were more common in the
antiepileptic drug-induced
psychotic disorder group (100% versus 72.6% and 76.9% versus 38.1%, respectively; P < 0.05). The percentage of continuous treatment with
antipsychotic drugs was lower in the
antiepileptic drug-induced
psychotic disorder group (15.4% versus 66.7%, P < 0.01). No patients experienced a chronic course in
antiepileptic drug-induced
psychotic disorder group whereas 40.5% did in non-
antiepileptic drug induced
psychotic disorder (P < 0.05). Our findings indicated that one in seven patients with
epilepsy who developed
psychosis had
antiepileptic drug-induced
psychotic disorder. In these patients, female gender, temporal lobe involvement and current use of
levetiracetam were significantly associated with
antiepileptic drug induced
psychotic disorder compared to other types of
psychosis, while
carbamazepine had a negative association. Disorganized behaviours and thinking were predominant in
antiepileptic drug-induced
psychotic disorder. Patients with
antiepileptic drug-induced
psychotic disorder differed from non-
antiepileptic drug-induced
psychotic disorders in having better outcome.