Negative thoughts weaken immunity

Having negative thoughts could make one more prone to illness, according to scientists. A recent study links "negative" brain activity with a weak immune system. Researchers from the University of Wisconsin-Madison, USA studied people with high levels of activity in a region of the brain linked to negative thoughts. They studied 52 people aged between 57 and 60. Each of them was asked to recall an event which made them feel very happy, and one which left them feeling sad, afraid or angry. Emotions play an important role in modulating body systems that influence our health. The electrical activity in certain parts of the brain was measured to check whether their left or right pre-frontal cortex was more active. Afterwards, each volunteer was given a standard flu vaccine shot. Vaccines work by eliciting an immune response which should persist and help the body tackle a genuine infection threat if it should arrive. Each research subject was tested over the following six months to gauge the success of the vaccine by measuring the levels of antibodies generated by the vaccine.

Scientists found that pessimists - people rated as more sensitive to negative events - show more activity in a part of the brain called the right pre-frontal cortex. Those with the highest activity levels responded worse to a flu vaccine. More activity in the left pre-frontal cortex is linked to positive emotional responses. Those who had shown the most powerful right pre-frontal cortex activity also had the worst immune reactions. The reverse was true for those who had the most powerful reactions in their left pre-frontal cortex, the side associated with happy reactions. This study shows that the mind influences the body to a great extant.

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