Immediate and delayed effects of risperidone on cerebral metabolism in neuroleptic naïve schizophrenic patients: correlations with symptom change

• Published in: Journal of neurology, neurosurgery and psychiatry Vol. 72; no. 1; pp. 106 - 110
• Main Authors: Ngan, E T C, Lane, C J, Ruth, T J, Liddle, P F
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd 01.01.2002; BMJ; BMJ Publishing Group LTD; BMJ Group
• Subjects: Adult; Adult and adolescent clinical studies; Biological and medical sciences; cerebral metabolism; CGI1; clinical global impression severity scale; Drug dosages; Energy Metabolism - drug effects; EPS; extrapyramidal side effects; FDG; Female; fluorodeoxy glucose; Frontal Lobe - diagnostic imaging; Frontal Lobe - drug effects; Gene expression; Hallucinations; Humans; Hypotheses; Imaging, Three-Dimensional; Male; Medical sciences; Metabolism; neuroleptics; Neuropharmacology; Pharmacology. Drug treatments; Psychiatric Status Rating Scales; Psycholeptics: tranquillizer, neuroleptic; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Psychopharmacology; Psychoses; Psychosis; Psychotropic drugs; risperidone; Risperidone - adverse effects; Risperidone - therapeutic use; SANS; SAPS; scale for assessment of negative symptoms; scale for assessment of positive symptoms; Schizophrenia; Schizophrenia - diagnostic imaging; Schizophrenia - drug therapy; Single-Blind Method; Studies; Tomography, Emission-Computed; Radionuclide study; Human; Statistical analysis; Neuroleptic; Psychotropic; Treatment efficiency; Schizophrenia; Exploration; Temporal cortex; Frontal cortex; Metabolism; Psychosis; Symptomatology; Chemotherapy; Delayed response; Treatment; Medical imagery; Immediate response; Risperidone; Positron emission tomography; Emission tomography; Brain (vertebrata)
• ISSN: 0022-3050; 1468-330X
• DOI: 10.1136/jnnp.72.1.106

Objective: Different symptom patterns have been shown to be associated with specific patterns of cerebral metabolic activity in schizophrenia. Treatment with various neuroleptic drugs results in decreased metabolism in frontal cortical regions. The temporal and regional relation between changes in metabolism and symptom improvement after treatment with risperidone was studied in eight previously unmedicated schizophrenic patients. Method: Cerebral metabolic activity was measured using PET before neuroleptic exposure, after the first dose of risperidone, and after 6 weeks of treatment. Pearson correlations were calculated for regions of significant change in metabolism and symptom change. Results: After 6 weeks of treatment significant deactivations were seen in the left lateral cortical frontal region and medial frontal cortex. Significant changes were detectable in the medial frontal region 90 minutes after the first dose of risperidone. Patients with higher baseline activity in the identified medial frontal cluster had higher baseline positive symptom scores and reduction in medial frontal metabolism was correlated with reduction in positive symptom score. Conclusion: The evidence suggests that the reduction in medial-frontal activity after treatment with risperidone is a direct effect of risperidone and not a consequence of symptom improvement. Reduction of medial frontal metabolism may be one of the physiological mechanisms by which risperidone alleviates symptoms of psychosis in schizophrenia.