Mode of transmission of schizophrenia.
OBJECTIVE
Although the evidences for the phenomenon of "anticipation" and parental "imprinting" have been shown in schizophrenia, they are inconclusive. The purpose of this study was to test these hypotheses by examining three successive generations.


METHODS
58 schizophrenic patients who had their maternal or paternal parent or grandparent, or both, affected with schizophrenia or related disorders were analyzed. Chi-square test was used to assess the association of the sex of the parent with more than one of the affected proband families. The differences in the age of onset of the illness between the successive three generations was calculated using the t-test.


RESULTS
In comparison to mothers' affected families, a large proportion of the father side affected families had more than one of their offspring affected with the illness. The age of onset in probands was lower in comparison to that of those on the parental side and the difference was more significant when the paternal side was affected. Interestingly, when the age of onset in the grandparents was compared with either of the parental sides of the probands no difference emerged, indicating lack of support from this study for the theory of anticipation. At any rate, the age of onset of probands was significantly lower in comparison to that of the paternal grandfather side. Further, skipping of a generation in the process of transmission was noted in some families.


CONCLUSIONS
It is hard to ignore our findings that suggest paternal side transmission.
Department of Psychiatry, Sri Ramachandra Medical College & Research Institute, Porur, Chennai 600116, India.
R
R
Ponnudurai
J
J
Jayakar