Schizophrenia a By-Product of Evolution?

A recent study has connected the psychological disease schizophrenia to increased brain size and metabolic ability. By testing healthy human brains, as well as certain monkey brains, against brains of diagnosed schizophrenics, the indication was that evolutionary development is responsible for increased psychological disorders.

Schizophrenia is a psychological disorder characterized by distorted perceptions of reality. These distortions can take the form of delusions and paranoia, and sometimes the famed “multiple personality” syndrome. Schizophrenia also diminished the capacity for speech and social interactions. Past research has suggested early life psychological trauma and genetics as major causes of schizophrenia, but this current study has uncovered an evolutionary explanation to the disease.

Healthy and schizophrenic human brains were studied against chimpanzee and rhesus macaque brains. Chimpanzees and rhesus macaques are known to be two of human beings closest progressive evolutionary descendants. The researchers “identified molecular mechanisms involved in the evolution of human cognitive abilities by combining biological data from two research directions: evolutionary and medical,” says study author Dr. Philipp Khaitovich.

The researchers found a striking parallel between alterations that occur in the brains of schizophrenics and natural alterations that occurred through human evolution. More specifically, the increased metabolic capacity and brain size brought about in the evolution of our species closely resembles what occurs in schizophrenic brains. “Our new research suggests that schizophrenia is a by-product of the increased metabolic demands brought about during human brain evolution,” says Dr. Khaitovich.

The human brain is an extremely complex and poorly understood neurological network. While this study only demonstrates a potentially important connection, it should lead to further research that better utilizes the idea that certain psychological disorders are a product of evolutionary brain development.

Source: Defeat Diabetes Foundation: Baldwin, Graeme. Khatovich, Philipp. Genome Biology news release. August 2008.