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Science / Schizophrenia

Schizophrenia and the Genetic Question

On September 15th, the American Journal of Psychiatry published a study from a group of scientists at Washington University in St. Louis, led by researcher C. Robert Cloninger, claiming that the mental disease schizophrenia is actually eight distinct disorders, as evidenced by eight different genetic origins. The study claims that though each disorder is expressed through identical symptoms – delusions, hallucinations, disordered thinking, and paranoia, to name a few – there are multiple genes, and combinations of genes working in concert, that could be responsible for causing them. This helps explain the confusing results from past studies examining the heritability of schizophrenia. The studies failed to distinguish between the eight disorders, lumping them all together under the broad title of schizophrenia.

The news stimulated interest beyond the scientific community, making international headlines and giving sufferers hopes of new, more targeted treatment. However, it is more likely that this study is yet another false promise in the mental health world’s quest for purely genetic explanations of illness. A group of geneticists have already posted criticism – albeit non-peer reviewed – of the Cloninger study on prominent genetics blog Genomes Unzipped, accusing it of being unrepeatable and unjustified by the evidence and analyses presented.

Subjectivity plays a larger role in psychiatry than in any other medical field. A treatment’s success or failure is measured qualitatively. Meanwhile, the presence of many unknown factors in the brain’s physiology makes it difficult to prove any conclusive claims about medicine and treatment. But our knowledge of mental health is changing rapidly. Alluring new discoveries link the symptoms of diseases like schizophrenia and depression to physiological genetic differences in a sufferer’s brain. Neat and tidy explanations for complex disorders hold the implicit promise of similarly neat and tidy treatments. And the idea of perfect genetic explanations is not out of the realm of possibility; with the rate of studies being conducted, medical research is coming closer and closer to understanding the true environmental and genetic causes of illness. It has even demonstrated that certain major mental illnesses, such as ADHD, depression, autism, schizophrenia and bipolar disorder, are connected to the same inherited genetic variations.

Confirmation of genetic roots for mental illnesses has benefits beyond the development of more targeted treatment. It heralds a fundamental shift in how sufferers are viewed, particularly those with ADHD and depression. Because these two disorders are diagnosed primarily according to displayed symptoms, which is important because everyone suffers to different degrees and goes to different lengths to ensure they receive the best treatment. Sufferers make these decisions according to the availability of medical resources, their level of medical education, and cultural tendencies. The widespread backlash against “big pharma” accuses drug companies and those who prescribe medications of exaggerating the efficacy of antidepressants and ADHD medication to extremes, or of prescribing medication to individuals who may display some symptoms of disorder but are not truly unhealthy. Such claims about so-called “cosmetic pharmacology” drugs, which elevate a person’s social or intellectual state beyond what is normal, are only a part of the broader conversation that stigmatizes mental illness.         Having a genetic explanation for the cause of schizophrenia or depression would help remove stigma and guilt from the sufferer. In many non-Western cultures, a pervasive shame surrounds mental illness that often impedes patient decisions to seek recovery. Conversely, a Western view of mental health disorders as physical disease makes those with schizophrenia or depression seem more broken and distant from healthy people than if they are believed to have developed the disease environmentally.

The ability to definitively diagnose of mental illness could help reduce stigma. Such diagnostic tools could soon become reality; researchers in Chicago are currently developing of a blood test to quickly and objectively diagnose patients with depression. All signs point to physiological indications of mental illness becoming more obvious.

Despite the ongoing controversy, public views of mental illness have shifted in the last half-century towards an at least partly genetic model. Increasingly, people of all cultures use vocabulary like, “chemical imbalance” and “brain disease” when describing depression or schizophrenia. The treatment of mental illness as a disease like any other is a helpful framework, for it takes blame away from the individual, and gives him a better grip on his identity beyond the doctor’s diagnosis.

The jury is still out on the degree to which these mental illnesses are environmentally triggered or genetically predetermined. But what would be the ramifications of a shift towards treating mental illness like physical illness? As this possibility grows ever more likely, the ways we view the mentally ill will adapt to the latest science.