Psychosocial factors in the pathogenesis of mental disorders

In an interesting Editorial, Leon Eisenberg (2004) discussed the possible impact of the recent advances in genetics and genomics on social psychiatry. He suggested that these advances, instead of diminishing the importance of social psychiatry, will instead enhance it.

In this context, psychosocial factors may be important environmental factors in the pathogenesis of primary (idiopathic) mental disorders. Several lines of evidence suggest that the primary mental disorders are a product of the evolution of the human brain and mind (Abed, 2000; Peedicayil, 2001). Among the many hypotheses proposed to explain this evolution, the most plausible is the social brain hypothesis, which has also been referred to as the Machiavellian intelligence hypothesis (Dunbar, 1998). According to this hypothesis, the human brain, especially the neocortex, evolved to the relatively large size it has because of the computational demands of the complex social system of primates.

Epigenetics (heritable changes in gene expression that occur without a change in DNA sequence) is thought to have played a major role in the evolution of the human brain (Rakic, 1995), and it is known to involve marked environmental inputs (Strohman, 1997). Hence, by extension, psychosocial factors may be important environmental factors in the pathogenesis of the primary mental disorders.