We studied 8 patients with frontal or temporolimbic neoplasms who had psychiatric presentations to clarify diagnostic criteria for distinguishing psychiatric disease from structural brain lesions and to examine brain-behavior relationships associated with cerebral neoplasms using modern neuroimaging techniques. Medical records were retrospectively reviewed for evidence of neurobehavioral and neurologic manifestations, tumor histologic features, and the results of treatment. Clinical presentations were correlated with tumor location as determined by computed tomography and magnetic resonance imaging. Patients with frontal lobe tumors presented with abulia, personality change, or depression, whereas those with temporolimbic tumors had auditory and visual hallucinations, mania, panic attacks, or amnesia. After treatment, neurobehavioral syndromes abated or resolved in 7 of 8 patients. We recommend that any patient 40 years of age or older with a change in mental state, cognitive or emotional, should have neuroimaging of the brain. Any patient with a psychiatric presentation who has specific neurobehavioral or neurologic findings or an unexpectedly poor response to psychopharmacologic treatment should also have brain imaging. These case reports extend and update observations on the importance of frontal and temporolimbic systems in the pathogenesis of neurobehavioral disorders.