Human Behavioral Disorders Research Articles

Genetics, Interaction, and Mental Illness: Setting the Problem

Probably no other approach to the understanding of behavior has met more enduring opposition than that which includes the possibility of hereditary contributions underlying man's intellectual or emotional development, normal or abnormal. Nearly everyone has found it easy to acknowledge the coexistence of inherited and environmental factors in the instinctive behavioral patterns of insects, birds, and other animals, and not too difficult, either, to concede a possible role played by heredity in some higher-order behaviors of animals other than man. In a few specific disorders of human behavior, such as Huntington's chorea or phenylketonuria, also, a genetic basis has long been recognized. But, on the whole, the idea that genes could have much to do with the complex activities of human mental life has gained only slow acceptance in most of the behavioral sciences and mental health professions. To many workers in these fields, the idea is still remote, despite a growing tendency in the literature to give at least a nod to the concept of gene-environment interaction .

Three Adoption Studies of Heredity in the Schizophrenic Disorders

Research in the genetics of human behavioral disorders* confronts a complex of problems from the moment of its inception. First of all, how does one go about doing this research when one obviously has no leverage on the implicated genes per se? One cannot engage in the traditional forms of experimental breeding, so that one has no control at all over the breeding of his sample population; and that is as it should be. No matter which behavioral disorder one studies, it is apparent from the outsetand always has beenthat its distribution in families follows no Mendelian pattern. What are we talking about, then, when we talk about the genetics of such disorders? The truth is that much of psychiatric genetics has been devoted to explaining awaynot explainingthe non-Mendelian distributions found. Initially, there was a predilection for positing such factors as reduced penetrance and varying manifestation in homozygotes and heterozygotes, depending on whether one's own preference was for a of dominance or recessiveness. Such theories? are based, in turn, on empirical statistical distributions that are fallibly determined and that vary appreciably from sample to sample and from study to study. In more recent times, the tendency has been to turn away from such theorizing and either to postulate a simple, additive, polygenic system to explain away the non-Mendelian distributions or to speculate that such disorders are genetically heterogeneous, i.e., that there are a number of different major single-genes at different loci that can lead to the same type of disorder. It is a simple matter for any investigator to choose to believe one kind of rather than another, and the fact is that the variety and abundance of theories that have been proposed in the past fifty years constitute an eloquent testimonial to the fact that we have been offered articles of faith and fancy rather than hard substance on which to develop a genetic theory of human behavioral disorders.

Human behavior, medicine and social reform.

The medical treatment of disorders of human behavior has not distinguished itself with scientific success. Students of the etiology of antisocial behavior have produced more theories in explanation than facts in clarification. Specifically, drug addiction, an antisocial disorder of human behavior, has been seen as both sickness and "badness"; it has been treated as sickness by social reformers and as "badness" by a punitive society, rarely simultaneously and in co-operation. The nature versus nurture controversy has droned on endlessly without resolution. The questions are posed and remain unanswered. Was this patient's troublesome behavior inbred, or was the behavior learned by . . .

On the application of genetic expectancies as age-specific base rates in the study of human behavior disorders.

On the application of genetic expectancies as age-specific base rates in the study of human behavior disorders.

PHILADELPHIA PSYCHIATRIC SOCIETY

The scientifically unproductive nature-nurture controversy in relation to disorders of human behavior, particularly schizophrenia and the manic-depressive psychosis, will cease as soon as it becomes generally accepted that an understanding of the principles of human genetics is indispensable for many diagnostic, therapeutic and preventive purposes of psychiatry. The need and feasibility of a consistent system of diagnostic classification with respect to schizophrenic, manic-depressive and involutional psychoses are indicated by a comparative analysis of the taint distribution observed in a total of 6,115 blood relatives (parents, siblings and co-twins) of statistically representative samples of psychotic twin index cases (1,232 twin index families). There is no evidence supporting either the popular hypothesis of a genetic relation between the entities of schizophrenia and manic-depressive psychosis (in the sense of interchangeable or somehow complementary genie elements of causation) or their pessimistic relegation to the status of semantic conventions. It is safe to assume that the mode of inheritance is that of a single recessive in schizophrenia and an irregularly dominant in manicdepressive psychosis. The principal genetic affinity of involutional psychosis is to the group of schizoid personality traits, and therefore at least indirectly to the schizophrenic disease entity, rather than to that of the manic-depressive psychosis.