Related Experiment Videos
Platelet MAO activity in hallucinating and paranoid schizophrenics: a review and meta-analysis
1Department of Psychiatry, Case Western Reserve University School of Medicine, OH 44106.
Abstract:
Published studies of platelet monoamine oxidase (MAO) activity of paranoid (P) and nonparanoid (NP) schizophrenics and normal controls, and of hallucinating (H) and nonhallucinating (NH) schizophrenics and normal controls were critically reviewed, and summary analyses were conducted on the original published data. Methods of comparing results across studies are discussed. Meta-analysis of the results of 11 analyses from 9 studies, examining a total of 165 P and 152 NP schizophrenics and 985 normal controls, indicated that the typical P schizophrenic studied had platelet MAO activity lower than that of 61% of NP schizophrenics and 79% of normal controls. Meta-analysis of the results of 8 separate analyses from 6 studies comprising 130 H, 81 NH schizophrenics, and 186 normal controls indicated that the average H schizophrenic studied had platelet MAO activity lower than that of 84% of NH schizophrenics and 80% of normal controls. In comparison with normal control values, P schizophrenics had the greatest mean percentage decrease in platelet MAO activity (30%), followed by NP schizophrenics (24%), and H schizophrenics (24%). These findings could not readily be attributed to diagnostic, demographic, or methodological factors, nor to the effects of alcohol or neuroleptics.
Insights
Paranoid and hallucinating schizophrenics exhibit lower platelet monoamine oxidase (MAO) activity compared to nonparanoid individuals and healthy controls. This finding suggests a potential biomarker for specific schizophrenia subtypes.
Area of Science:
- Neuroscience
- Psychiatry
- Biochemistry
Background:
- Platelet monoamine oxidase (MAO) activity has been investigated as a potential biomarker in schizophrenia.
- Previous studies have yielded varied results regarding MAO activity in different schizophrenia subtypes.
Purpose of the Study:
- To critically review and synthesize published data on platelet MAO activity in paranoid (P), nonparanoid (NP), hallucinating (H), and nonhallucinating (NH) schizophrenics compared to normal controls.
- To conduct meta-analyses to determine the typical differences in platelet MAO activity across these groups.
Main Methods:
- Systematic review and meta-analysis of published studies on platelet MAO activity.
- Inclusion of data from 9 studies (165 P, 152 NP schizophrenics, 985 controls) and 6 studies (130 H, 81 NH schizophrenics, 186 controls).
- Comparison of mean platelet MAO activity across patient groups and normal controls, accounting for potential confounding factors.
Main Results:
- Paranoid schizophrenics showed significantly lower platelet MAO activity than 61% of nonparanoid schizophrenics and 79% of controls.
- Hallucinating schizophrenics had lower platelet MAO activity than 84% of nonhallucinating schizophrenics and 80% of controls.
- Mean percentage decrease in platelet MAO activity compared to controls was greatest in P schizophrenics (30%), followed by NP (24%) and H (24%).
Conclusions:
- Lowered platelet monoamine oxidase (MAO) activity is a consistent finding in paranoid and hallucinating schizophrenia subtypes.
- These alterations in MAO activity are not readily explained by diagnostic, demographic, methodological factors, or medication/substance use.
- Platelet MAO activity may serve as a potential biological marker differentiating schizophrenia subtypes.