Lefties at higher risk for psychotic disorders

A new small study done by researchers at Yale, finds that among people with mental illnesses, those with psychotic disorders like schizophrenia are far more likely to be left-handed. The findings were published in the October issue of the journal SAGE Open.

Study leader Jadon Webb and his team conducted an analysis of 107 people who were being treated at an urban, low-income, psychiatric clinic and compared the number of left-handed patients who were identified with various mental disorders.

The researchers found that 11 percent of those diagnosed with mood disorders such as depression and bipolar disorder were left-handed, which wasn’t surprising since it mirrors the general population. About 10 percent of the U.S. population is left-handed.

But strikingly, the team found that 40 percent of the group who were diagnosed with schizophrenia was left-handed.

Webb hopes the discovery may lead to better treatment options.

“In general, people with psychosis are those who have lost touch with reality in some way, through hallucinations, delusions, or false beliefs, and it is notable that this symptom constellation seems to correlate with being left-handed,” said Webb in a news release. “Finding biomarkers such as this can hopefully enable us to identify and differentiate mental disorders earlier, and perhaps one day tailor treatment in more effective ways.”

The study is admittedly small, but the way it was conducted made it highly effective, Webb said. Patients at the clinic were simply asked, “What hand do you write with?”

“This told us much of what we needed to know in a very simple, practical way,” said Webb. “Doing a simple analysis meant that there were no obstacles to participating and we had a very high participation rate of 97 percent.