25 October 2007

Stress + darkness = fear

A new study shows that darkness increases the impact of social stress and sheds light on our inherent fear of the dark.

Just in time for Halloween, researchers are releasing new data that show darkness increases the impact of social stress. As children and adults alike gear up for the anticipation and excitement of this “spooky” holiday, this study lends a further understanding to our inherent fear of the dark.

Dr Christian Grillon and colleagues at the National Institute of Mental Health sought to examine whether stress increases unconditioned fear in humans. To do this, they measured the startle reflex of healthy volunteers in either light or dark conditions, and after either a socially stressful situation of public speaking, or after a period of relaxation.

Measuring the startle response
The startle response is a sensitive tool for measuring anxiety levels, and in this study, was measured when volunteers were presented with white noise stimuli via headphones.

The authors found that the startle response was boosted when the volunteers were in complete darkness, and this effect was more pronounced after the stressor.

Grillon explains, “Because stress has been linked to the precipitation of emotional disturbances, sometimes to a pathological level, it is important to understand how stress affects our brain and behaviour.” He adds, “We report that a mild acute stressor increases subsequent experimental anxiety in healthy subjects.”

John H. Krystal, M.D., Editor of Biological Psychiatry and affiliated with both Yale University School of Medicine and the VA Connecticut Healthcare System, comments: “The authors show that social stress and darkness interact to increase the startle response. The refinement of this research method may help us to understand how threatening contexts and stressful social interactions interact at a mechanistic level to contribute to anxiety disorders." – (EurekAlert!)

Source: Biological Psychiatry

Read more:
Reason to be afraid of dark


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