"It's the first time I attempted to write something for people other than for my peers," Dr. [Irving I. Gottesman] noted during a recent interview in his book- filled office in Gilmer Hall at the University of Virginia. Dr. Gottesman is commonwealth professor of psychology in U.Va.' s psychology department.

Dr. Gottesman said last week, for example, that among twins there's a relation between how ill a twin is and the chances that the second twin may develop schizophrenia. If the twin who has the disease is severely ill, he said the chances are about 75 percent that the second twin will develop the disorder.

Dr. Gottesman said he believes that just a limited number of genes, which have relatively large effects, are involved in the disorder, and because dopamine seems to be involved with schizophrenia, "it would pay to look at genes in the dopamine receptor system."