In this cross-sectional study, the neuropsychiatric profiles of 42 patients with juvenile myoclonic epilepsy (JME) who were treated with valproate (VPA) or topiramate (TPM) in monotherapy were compared with the aim of verifying the relationship between cognitive dysfunction, psychiatric disorders, and factors related to epilepsy. Patients with JME taking VPA 500-1750 mg/day or TPM 50-175 mg/day were selected. For all patients, psychiatric profiles were evaluated with the Scheduled Clinical Interview, axes I and II (SCID I and SCID II), or the Brazilian version of the Schedule for Affective Disorders and Schizophrenia for School-Aged Children (K-SADS-PL). Neuropsychological measures included intellectual functions, attention, memory, executive functions, and language. Patients taking TPM exhibited worse neuropsychological performance on attention, short-term memory, processing speed, and verbal fluency functions related to frontal lobes, which may be dysfunctional in JME. Anxiety disorders were associated with lack of seizure control and having had more than 20 lifetime generalized tonic-clonic seizures.