The immune system is a key factor in the etiology of psychosocial disease.

The immune system is proposed as the key to understanding the etiology and treatment of psychosocial disease. There is a dense communication network between the immune system and the central nervous system (CNS). Immune cell cytokines, via direct action on the CNS, induce fever, alter sleep, pain perception and pituitary hormone release and reduce appetite and activity in animals. Interleukin-2 and interferon given to humans result in global behavioral and cognitive pathology. Activation of the immune system by pathogens produces global cognitive and behavioral pathology also. Recently, controlled trials have demonstrated that diet can cause psychosocial disease, presumably by an immune mechanism. Immune system abnormalities have been identified in manic-depressive psychosis, schizophrenia and alcoholism. Lithium carbonate is not only prophylactic for all three of these diseases, but it also powerfully stimulates the immune system. This is proposed as the mechanism of lithium's therapeutic effect. The antipsychotics, haloperidol and the phenothiazines, affect the immune system also. The rapid development of AIDS dementia complex can be explained by the remarkable influence the immune system has on the CNS.