Alcohol-induced psychomotor performance impairment in young adult drinkers with alcohol usage disorders

By Pooja Toshniwal PahariaReviewed by Danielle Ellis, B.Sc.Jun 20 2023

In a recent study published in Alcohol: Clinical & Experimental Research, researchers examined alcohol-induced psychomotor performance impairments among young adult alcohol consumers with alcohol usage disorders (AUDs).

Background

Acute alcohol intoxication leads to executive and psychomotor function deficits, often resulting in significant harm, such as impaired driving and accidents. Studies have reported that moderate-to-high alcohol intake (0.5 to 1.0 g per kg) increases reaction time, impairs motor coordination, and decreases performance on driving simulation and information processing tasks.

Further, alcohol intake disrupts reasoning, judgment, and decision-making, which may impair subjective perceptions of behavioral performances. Behavioral tolerance to the intake of alcohol indicates that regular consumers have lowered sensitivity to the impairing effects of alcohol. However, most previous studies evaluating alcohol-induced impairments have emphasized social drinking, limiting data on acute behavioral impairments among heavy drinkers (HDs) and AUD drinkers.

About the study

In the present cross-sectional study, researchers characterized behavioral tolerance in psychomotor function across different phenotypes of alcohol drinkers.

The team evaluated data from 397 Chicago Social Drinking Project (CDSP) participants to evaluate the impact of alcohol intake on psychomotor cognitive performance among 86 light drinkers (LDs), 208 HDs, and 103 AUD individuals. At baseline and 30 minutes, 60 minutes, 120 minutes, and 180 minutes after consuming 0.80 g per kg of alcohol [the ‘usual high’ dosage; peak breath alcohol concentration (BrAC) was 0.10 g per dL] or a placebo beverage in two sessions, individuals completed the Grooved Pegboard test to evaluate fine motor skills and the Digit Symbol Substitution Task (DSST) to evaluate perceptual-motor processing.

In addition, the study participants filled out self-reported surveys of perceived impairments and completed the alcohol quantity frequency and previous-month cigarette and alcohol timeline follow-back interviews. Sixty AUD drinkers participated in a third, single-blinded experimental session with 1.20 g per kg of alcohol (the ‘very high’ dosage, peak BrAC of 0.1 g per dL).

LDs and HDs were enrolled from 2004 to 2011, whereas alcohol consumers with AUD were enrolled from 2016 to 2019. The team included only healthy individuals 21.0 to 35.0 years of age who weighed between 110.0 and 210.0 pounds, and among women, only non-pregnant and non-lactating women. In addition, all included AUD individuals scored below 10.0 on the revised Clinical Institute Withdrawal Assessment of Alcohol Scale (CIWA-Ar) at participant screening and before each experimental session.

LDs consumed ≤6.0 drinks weekly with rare episodes of binge drinking; HDs consumed ≥10.0 drinks weekly with one to five episodes of heavy drinking weekly; and AUD drinkers consumed ≥28 drinks weekly (or ≥21 drinks for females) with ≥11.0 episodes of heavy drinking monthly. The team excluded individuals with substance use (except nicotine) or psychiatric disorders and those with positive results on alcohol breath analyzers, urine toxicology screening [other than tetrahydrocannabinol (THC)], and hepatic abnormalities. Logistic regression modeling was performed by adjusting age, sex, level of education, family history of AUD, and cigarette and cannabis use, in addition to generalizing estimating equations (GEEs) and correlation tests.

Results

Compared to light and heavy drinkers, AUD drinkers perceived fewer impairments and greater behavioral tolerance to intoxicating doses of alcohol, as demonstrated by lowered peak psychomotor impairment followed by a swifter cognitive recovery to baseline levels. Among AUD individuals who consumed 1.20 g per kg of alcohol, impairments were two-fold higher than those observed after consuming 0.80 g per kg of alcohol and were greater than the psychomotor impairments in LDs after 0.80 g per kg of alcohol intake.

Compared to heavy and light drinkers, AUD drinkers showed worse psychomotor performance at baseline on the Digit Symbol Substitution Task, which seemed to be associated with their lower level of education. AUD drinkers and HDs, compared to LDs, showed comparatively greater behavioral tolerance to intoxicating levels of alcohol on the Pegboard and DSST measures, and they had a perception of being less cognitively impaired.

The findings indicate that behavioral tolerance observed among AUD individuals might be dose-based, as when consuming 1.20 g per kg of alcohol, they demonstrated considerable impairments on the tests.

The findings showed a positive association between the extent of alcohol intake and behavioral tolerance. Repeated exposure to alcohol may alter neural receptor function and neurocircuitry, especially concerning glutamatergic and gamma-aminobutyric acid (GABA)-ergic neurotransmission, impacting psychomotor performance.

Conclusions

Overall, the study findings showed that consuming intoxicating levels of alcohol greatly hindered psychomotor functioning across drinker phenotypes. HDs showed faster recoveries in performance with fewer peak impairments than LDs. Nevertheless, among AUD drinkers, the intake of 1.20 g per kg of alcohol more than doubled the psychomotor impairments compared to 0.80 g per kg of alcohol.

The findings indicated that AUD individuals were likely to retain more psychomotor function than light drinkers at moderate doses of alcohol, but when intoxicated by very high doses that more closely resembled their typical drinking levels, their fine motor abilities and working memory were significantly impaired.

Further research examining other psychomotor functions at varying alcohol doses could improve our understanding of behavioral tolerance across drinking phenotypes and their relationships with alcohol-associated harm and injury.