This is a prospective study of a consecutive series of children undergoing epilepsy surgery. The main aims were to evaluate the heterogeneity with respect to psychopathology and IQ, and to use a global assessment scale (Children's Global Assessment Scale [CGAS]) to evaluate psychosocial functioning. Clinical neuropsychiatric and neuropsychological assessments were made at baseline and at the 2-year follow-up in 24 patients, and changes were analyzed at an individual level. Psychiatric disorders (mainly attention deficit hyperactivity disorder and/or autism spectrum disorders) were found in 17 of 24 at some point. All except one child with psychiatric diagnoses before surgery still had at least one diagnosis at follow-up. Intellectual ability remained stable in the majority of cases, both in individuals with and in individuals without mental retardation. The CGAS illustrated the consequences of the extensive comorbidity in this cohort. The behavioral problems had been undiagnosed despite parental concern in many cases, indicating an unrecognized need for services for children with drug-resistant epilepsy.