Epilepsy may appear in comorbidity with other neurological disorders. Nevertheless, epileptic seizures and antiepileptic drugs may be responsible for the development of cognitive dysfunctions and mental disorders. Some epileptic seizures may develop with mood disorders, including depressive symptoms. Described in the present report is the case of a 23-year-old male patient with an 8-year history of partial epilepsy and a familial history of bipolarity. He had been treated for partial-onset seizures with carbamazepine and oxcarbazepine, and lamotrigine (LTG) was gradually added to treat depressive symptoms, reaching a twice-daily dosage of 100 mg. The patient developed paranoid delusions involving his neighbors, delusions which subsided after dosage was decreased to 150 mg/day. Seizure control was good, and psychiatric symptoms resolved when the dosage was decreased. Psychotic episodes resulting from rapid increase in LTG serum level has been documented.

Keywords: Acute psychosis, bipolar disorder, epilepsy, delusion, lamotrigine