Volumetric evidence of a left laterality effect in epileptic psychosis Renato Luiz Marchetti, a, * Dion  ısio Azevedo Jr., a C assio Machado de Campos Bottino, a DanielaKurcgant, a AndreadeF atimaHorvathMarques, a SuelyKasueNagahashiMarie, b and Paulo Correa Vaz de Arruda a a Institute and Department of Psychiatry, University of S~ ao Paulo, Rua Campevas 447, Perdizes, CEP 05016-010, S~ ao Paulo, Brazil b Department of Neurology, University of S~ ao Paulo, S~ ao Paulo, Brazil Received 8 October 2002; revised 24 February 2003; accepted 24 February 2003 Abstract We investigated anatomic alterations and lateralization effect in the mesial temporal lobe structures (amygdala and hippo- campus) in epileptic psychosis MRI volumetric measurements. Patients with epileptic psychosis and normal controls were studied. Lefthippocampusvaluesweresignificantlysmallerforpatients(P < 0:001).Hippocampalratiowassignificantlygreaterforpatients (P < 0:01). Group (patients  normal) was the only factor explaining the statistically significant variation of left hippocampus and hippocampal ratio (P < 0:001and P < 0:05).Twentypatientshadhippocampalatrophy(4ontherightside,15ontheleftside,and 1 bilateral) associated with mesial temporal sclerosis. These results confirm the existence of anatomic alterations and a left laterality effect in the mesial temporal lobe structures of patients with epileptic psychosis. Ó 2003 Elsevier Science (USA). All rights reserved. Keywords: Epilepsy; Magnetic resonance imaging; Mental disorders; Psychosis; Temporal lobe 1. Introduction Psychosis is one of the most important mental dis- orders occurring in people with epilepsy (PWE). A fre- quently asked question is: Is the association between epilepsy and schizophrenia random or etiological? The hypothesis of a specific epileptic psychosis (EP) is sug- gested by the increased prevalence of psychosis in PWE [1–3] and the increased prevalence of epilepsy in people with psychosis. EP affects mainly patients with temporal lobe epilepsy (TLE) [4–6], with epilepsy onset in early adolescence [7–10], and with psychosis onset after some years of epilepsy [11]. It is characterized by a modified schizophrenic presentation, with somewhat preserved affect and social functioning [5,12,13]. Participation of the temporal lobes in the genesis of EP is supported by the presence of epileptic discharges in the mesial temporal lobe region, mainly of the left side, on interictal EEG [7,11]. Participation of the tem- poral lobes in the genesis of psychosis associated with schizophrenia is suggested by anatomic abnormalities, with global reduction [14–16] and abnormalities in the mesial and lateral regions [17–19], mainly on the left side. However, contrary to what is found in schizo- phrenia, evidence of anatomic abnormalities in the temporal lobes of patients with EP, based on neuro- imaging findings, is inconclusive [5,7,8,20–25]. Our purpose was to investigate anatomic abnormalities and a possible lateralization effect in mesial temporal lobe structures (amygdala and hippocampus) in EP with magnetic resonance imaging (MRI) volumetric measurements. 2. Methods 2.1. Population Patients are referred to our unit for treatment of mental disorders associated with epilepsy. Neurological characteristics such as seizure or epileptic syndrome di- agnoses, resistance to treatment with antiepileptic drugs Epilepsy & Behavior 4 (2003) 234–240 www.elsevier.com/locate/yebeh Epilepsy & Behavior * Corresponding author. Fax: +55-11-3672-2426. E-mail address: rlmarche@dialdata.com.br (R.L. Marchetti). 1525-5050/03/$ - see front matter Ó 2003 Elsevier Science (USA). All rights reserved. doi:10.1016/S1525-5050(03)00056-8