13 April 2012

Worrying and intelligence evolutionarily inseparable

by Will Parker

Anxiety and excessive worry, traits that are usually viewed as maladaptive, appear to have co-evolved with the attribute that is viewed as most adaptive - human intelligence. Details of this intriguing research, led by Jeremy Coplan, professor of psychiatry at the State University of New York Downstate Medical Center, appear in the journal Frontiers in Evolutionary Neuroscience.

In the study, patients with generalized anxiety disorder (GAD) were compared with healthy volunteers to assess the relationship between intelligence quotient (IQ), worry, and the brain's processing of choline (a B-complex vitamin).

In a control group of normal volunteers, high IQ was associated with a lower degree of worry, but in those diagnosed with GAD, high IQ was associated with a greater degree of worry. The correlation between IQ and worry was significant in both the GAD group and the healthy control group. However, in the former, the correlation was positive and in the latter, the correlation was negative.

Coplan and his team found that high intelligence and worry both correlate with brain activity measured by the depletion of the nutrient choline in the subcortical white matter of the brain. According to the researchers, this suggests that intelligence may have co-evolved with worry in humans.

The researchers propose that the socially based evolution of humans may actually favor the expression of the genes responsible for high anxiety and worry. "While excessive worry is generally seen as a negative trait and high intelligence as a positive one, worry may cause our species to avoid dangerous situations, regardless of how remote a possibility they may be," speculated Coplan. "In essence, worry may make people 'take no chances,' and such people may have higher survival rates. Thus, like intelligence, worry may confer a benefit upon the species."

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Source: State University of New York Downstate Medical Center