'Drink fuelled memory blackouts' predict future injury risk

29 June, 2011

The higher the number of drink fuelled memory blackouts a student experiences, the greater is his/her risk of sustaining a future injury while under the influence, reveals research published online in Injury Prevention.

Memory blackouts refer to the inability to recall events; they do not refer to loss of consciousness as a result of drinking too much. Research indicates that alcohol alters nerve cell communication in the hippocampal region of the brain, which affects memory formation.

Hazardous drinking - and its consequences - "are pervasive on college campuses," say the authors, who report that around one in three students say they have experienced a memory blackout in the past year, and around one in 20 say they have had a period of drink fuelled amnesia within the past seven days.

Women are just as likely to have blackouts as men, even though they drink less.

In 2001, around 600,000 college students were injured as a result of excess drinking in the USA, and in 2005 almost 2,000 died as a result of booze fuelled unintentional injuries.

The authors therefore wanted to find out if the number of times a student had a memory blackout as a result of drinking too much could usefully predict who might sustain a potentially serious injury while under the influence in the future.

They analysed data from almost 800 undergraduates and more than 150 postgraduate students at five universities in North America between 2004 and 2009, who were monitored for two years.

The students were taking part in the College Health Intervention Project Study (CHIPS), which compared the value of screening and brief doctor-led interventions versus nothing for problem drinking, assessed according to quantity and frequency.

During the previous 28 days, male problem drinkers had put away an average of just under 82 drinks (as opposed to units); their female peers had downed just under 59.

Men had more heavy drinking days, defined as five plus drinks, than women.

More than half of all the students had had one or more memory blackouts in the 12 months leading up to the start of the study; 7% reported six or more during this time.

Those aged between 18 and 20, "sensation seekers," and those clocking up the most heavy drinking days reported the highest number of blackouts.

The subsequent analysis showed that the overall prevalence of injury associated with alcohol was just over 25%, with women just as likely as men to be injured.

And the more blackouts they had, the greater was their risk of unintentional injury.

One to two memory blackouts increased the odds by 57%. With six or more memory blackouts, a student was almost three times as likely to sustain an injury.

"Our results suggest that memory blackout screening at student health services could be a useful tool in college alcohol related injury prevention," conclude the authors.

This would be more specific than simply asking a student how much s/he drinks, and would help pick up those whose drinking is disrupting their cognitive abilities, they add.

"It may be easier for a student to dismiss general health warnings on excessive alcohol drinking harms than to refute that his extreme alcohol drinking is causing impairment in brain function," they say.

Source: BMJ