Discriminant analysis of minor physical anomalies as dysontogenetic markers of schizophrenia

The aim of the study was to evaluate the predictive value of minor physical anomalies in the binomial model schizophrenic patient-mentally healthy subject as an index of developmental origin of schizophrenia.

Sixty-eight schizophrenic patients (38 males and 30 females) and 69 mentally healthy subjects (36 males and 33 females) of Bulgarian ancestry were examined for minor physical anomalies using the Waldrop Physical Anomaly Scale. The predictive value of minor physical anomalies for schizophrenia was determined by discriminant analysis.

The two-group discriminant analysis distinguishes well the schizophrenic patients from the controls with 6 predictive variables. The variables with significant contribution to prediction of the patient-control status are fine electric hair (p < 0.001), gap between I and II toes (p < 0.001), epicanthus (p < 0.001), high/steepled palate (p < 0.001), tongue with rough/smooth spots (p < 0.001), III toe > or = II toe (p < 0.001). The model overall correct classification is 78.63%, predicting slightly better the schizophrenics than the controls (79.7% vs. 77.4%).

The constellation of variables entered into the discriminant analysis model confirms the hypothesis that at least in one subpopulation of schizophrenic patients the minor physical anomalies reflect early developmental processes determining occurrence of the disease in later periods of life.