Archive for April 20th, 2009

SOME ALLERGIC SYMPTOMS MAY AFFECT THE BRAIN AND CAUSE MENTAL PROBLEMS

Monday, April 20th, 2009

Less controversial is the notion that some allergic symptoms may affect the brain and cause mental problems, these being ‘secondary’ to the allergic response itself. In those with severe asthma, for example, the reduction in oxygen reaching the brain can cause changes in mood and abnormal behaviour. Lack of concentration, poor memory, ‘slowness’, drowsiness, depression, anxiety and irritability can all result from lack of oxygen.

Hay-fever and non-seasonal rhinitis (constant runny nose) can also have secondary effects on the brain. The congestion in the nose may result in the normal breathing pattern stopping entirely during sleep (sleep apnoea). This wakes the patient up and breathing starts again, but if there are repeated attacks during the night this can produce severe fatigue and drowsiness during the following day.

Overall, the evidence suggests that IgE-mediated allergy probably can affect the brain, either directly or indirectly. But the mechanism of direct action is unknown and the subject remains highly contentious. Nevertheless there is considerable evidence that the immune system interacts with both the nervous system and the hormones. This evidence, which will be looked at in the next section, is an indication that a direct link between allergy and mental problems is not impossible.

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