Recent Research on Alcohol's Links to Dementia
Recent newspaper articles have suggested that alcohol could be a major cause of dementia and that British people in particular may be about to suffer from problems with their memories, while they are still in their forties, or so the Daily Mail claimed, stating that alcohol could be a major contributor to ‘one in four cases of dementia’.
What’s the truth behind this claim, which suggests that a real epidemic of alcohol-linked mental problems could be about to hit the older population?
First, the sample was very small – only 55 participants completed the entire study and of that number, only 26 were classed as detoxified dependent drinkers, which is the medical term for alcoholics who have given up alcohol completely for a substantial period of time.
Second, the study was not established to discover what caused the memory deficits, only that they existed. It does appear to show that alcohol-dependent drinkers have more problems recalling specific autobiographical memories than non-alcohol dependent drinkers but it doesn’t show whether the difficulty is caused by alcohol or by other mental health issues that are associated with substance abuse.
How Was The Study Organised?The 26 detoxified drinkers were put with with 29 non-dependent drinkers and both groups were tested for a variety of mental health functions, such as symptoms of depression as well as taking part in an Autobiographical Memory Test which is what the results were based on. This test offers a cue to the participant who is then asked to recall a personal memory that is specific to that cue, such as the first time they experienced a particular event. As an example, a participant might be shown a Christmas card and asked to talk about the earliest Christmas they can remember. Every participant was questioned 18 times about different cues.
The Study’s OutcomesThis study found that alcohol dependent individuals had fewer distinctive personal memories than other people, with an average of 9.15 compared to 13.72. This difference was statistically significant - it could not be explained away by chance. This meant that when questioned, people who had been alcohol dependent had fewer memories of their own past that they could relate to a universal cue. While dependent drinkers could only remember a personal experience in their early years for 51% of the cues, non-dependent drinkers could recall a memory over 75% of the time. Dependent drinkers also took more time to identify a memory – around five seconds longer on average - and had higher depression scores.
What Does This Mean For Treatment Of Alcoholics?The research suggests that detoxified dependent drinkers demonstrate reduced memory skills which are very similar to those of other clinical conditions like depression or severe mental trauma. This is different to the condition Wernicke-Korsakoff syndrome (so called 'wet brain') which is a brain deterioration found only in alcoholics and those who have had drastic and rapid weight loss, thyrotoxicosis, cancer or renal dialysis. Wernicke-Korsakoff syndrome in drink dependent individuals does affect memory and can be fatal. While it can be treated when caused by other conditions, when it is linked to excess alcohol consumption it often resists treatment and can lead to institutionalisation for the rest of life.
While alcohol-related dementia is known to accounts for 10-24% of all cases of dementia worldwide, it’s not clear how alcohol interacts with dementia: whether it causes dementia to develop or whether dementia causes excessive drinking, or if there is a more complex interrelationship between these and other conditions.
In future, alcohol dependent people may be assessed for the onset of dementia much earlier, and studies of dementia sufferers will try to establish the causes of the relationship between memory loss, dementia and alcoholism and whether certain kinds of drinking, particularly the kinds of binge-drinking popular in the UK, contribute to the three conditions.
It is important to be aware that such a small study may have many evidence gaps – for example there may be links between the people in the study in terms of genetics, diet or behaviour that contribute to their conditions but were not picked up in the research.