Heavy drinking may harm men more than women

Contradicting prevalent belief, new research has found that heavy alcohol use may put men more at risk of long-term harm than women. The findings, presented at the annual European College of Neuropsychopharmacology meeting being held in Paris from September 2-5, suggest that long-term alcohol use can change brain functions and these changes are significantly different in men and women.

"We found more changes in brain electrical activity in male subjects, than in females, which was a surprise, as we expected it would be the other way around. This means that male brain electrical functioning is changed more than female brains by long-term alcohol use," said Outi Kaarre from University of Eastern Finland and Kuopio University Hospital, Finland.

A researchers worked with a small group of young men and women who had a heavy 10-year alcohol use, and compared them with another group men and women who had little or no alcohol use. All were between 23 to 28 years old at the time the measurements were taken.

The researchers examined the responses of the brain to being stimulated by magnetic pulses - known as Transcranial Magnetic Stimulation (TMS), which activates brain neurons. The brain activity was measured using EEG (electroencephalogram).

Previously, the researchers had found that heavy alcohol users showed a greater electrical response in the cortex of the brain than non-alcohol users, which indicates that there had been long-term changes to how the brain responds.

This time, they found that young men and young women responded differently, with males showing a greater increase in electrical activity in the brain in response to a TMS pulse.

The EEGs also allowed the researchers to show that male brains have greater electrical activity associated with the GABA (gamma-amino butyric acid) neurotransmission than do female brains.

GABA is a pretty fundamental neurotransmitter in the inhibition of many brain and central nervous systems functions. It is involved in many neurological systems, and is important in anxiety and depression. Generally it seems to calm down brain activity.

"Generally, our work showed that alcohol causes more pronounced changes in both electrical and chemical neurotransmission in men than women," Kaarre said.

"There are two types of GABA receptors, A and B. Long-term alcohol use affects neurotransmission through both types in males, but only one type, GABA-A, is affected in females," Kaarre added.

"We know from animal studies that GABA-A receptor activity seems to affect drinking patterns, whereas GABA-B receptors seem to be involved in overall desire for alcohol. It has been suggested that women and men may respond differently to alcohol. Our work offers a possible mechanism to these differences," Kaarre said.