A novel psychophysiological model of the effect of alcohol use on academic performance of male medical students of Belarusian State Medical University

Background: The blood glucose concentration might determine the degree of academic performance. Decrease in the glucose concentration leads to a lowering of cognitive functions. Objectives: To produce a model of students’ alcohol use based on glucose homeostasis control and cognitive functions. Methods: The study involved 13 male volunteers (8 moderate alcohol users and 5 non-alcohol users) – medical students and took 6.5 hours on fasting. Selection criteria were based on a screening survey conducted among students in Minsk, Belarus. Out of 1499 students, 185 were abstainers, 1052 – moderate drinkers, 262 – problem drinkers. The experiment was divided into three phases: first phase – the students were administered AUDIT, MAST, CAGE, STAI, Academic Performance questionnaires; second phase - the students worked with text № 1 (physiology of bone tissue and subsequently answered on the questions that followed it); third phase – with text № 2 (physiology of autonomic nervous system and also answered subsequently on the questions that followed it). Blood glucose level was measured at 2 hours intervals, including the initial level. Tests on short-term, long-term memory and attention were used in every phase of the experiment. The probability value for significance was set at p<0.05. Results: The moderate drinkers had significantly lower glucose concentration after 4-6 hours, compared to their initial concentration, as well as to the values of the abstainers. Disturbances in cognitive functions, precisely a decrease in the effectiveness of active attention and a faster development of fatigue after 4-6 hours of mental work in alcohol users, compared to abstainers was statistically proven. The Intellectual Capacity on various tests/tasks positively correlated with the blood glucose level and in the 2-3 phases of the experiment and according to the results of the academic performances (ρ = +0.75; p<0.01). Alcohol users had 12.5–40.0 times higher number of errors on various tests/tasks than the non-alcohol users (p<0.001). The errors made on various tests/tasks increased with decrease in the blood glucose concentration (ρ = – 0.83; p<0.01). Significant increase in the Visual Productivity Coefficient among abstainers was also observed (p<0.05). Conclusion: This is the first study to show that alcohol use, even in episodic moderate doses (28ml/person with 1-2 times frequency per month) is accompanied by long-term glucose homeostasis disorders, leading to cognitive function disturbances and a decrease in the effectiveness of mental activities. These disorders in gluco