Minor Physical Anomalies and Quantitative Measures of the Head and Face in Patients With Psychosis
McGrath J, El-Saadi O, Grim V, Cardy S, Chapple B; Chant D; Lieberman D; Mowry B. ;
Commented by , 13 Jun 2002
Aim of the study
Previous studies had provided some evidence that patients with schizophrenia have more minor physical abnormalities compared with controls. In particular, these studies had shown that minor physical abnormalities of the head and face best discriminate patients with schizophrenia from controls. Therefore, the authors examined minor physical anomalies and quantitative measures of the head and face in patients with psychosis versus healthy controls using an epidemiologically sound procedure.
Method
During a comprehensive Australian prevalence study 2180 individuals were screened for psychosis. Of 1513 screen positive individuals, 310 were randomly selected as were 303 controls who were drawn from the same catchment area via advertisements in local newspapers. From this sample, 180 case-control pairs were matched for age and sex.
Individual minor physical anomalies and quantitative measures related to head size and facial height and depth were compared within the matched pairs. Based on all subjects, the authors examined the specificity of the findings by comparing craniofacial summary scores in patients with nonaffective or affective psychosis and controls.
Results
The odds of having a psychotic disorder were increased in those with wider skull bases (odds ratio [OR], 1.40; 95% confidence interval [CI], 1.02-1.17), smaller lower-facial heights (glabella to subnasal) (OR, 0.57; 95% CI, 0.44-0.75), protruding ears (OR, 1.72; 95% CI, 1.05-2.82), and shorter (OR, 2.29; 95% CI, 1.37-3.82) and wider (OR, 2.28; 95% CI, 1.43-3.65) palates. Compared with controls, those with psychotic disorder had skulls that were more brachycephalic.
These differences were found to distinguish patients with nonaffective and affective psychoses from controls. No significant differences between affective and nonaffective (mainly schizophrenic) psychoses were found.
Discussion
These results are of course not of any diagnostic value, but they give more insight in organic causes of psychotic disorders. The authors discuss that the reason for these minor physical abnormalities may be genes related to psychosis. Furthermore, risk factors for schizophrenia such as prenatal virus exposures, obstetric complications, general nutritional deficiencies and low prenatal vitamin D, in particular, are also know to affect craniofacial growth.
The main limitations are that due to the design of the study patients with chronic, persisting types were overrepresented. In addition, measures were taken externally on subjects, so that differential thicknesses of superficial soft tissues of the skull could have in part contributed to group differences.
The authors discuss that several of the features that differentiate patients from controls relate to the development of the neuro-basicranial complex and the adjacent temporal and frontal lobes. They suggest that future research should examine both the temporal lobe and the middle cranial fossa to reconcile our anthropomorphic findings and the literature showing smaller temporal lobes in patients with schizophrenia. Closer attention to the skull base may provide clues to the nature and timing of altered brain development in patients with psychosis.