Researchers have discovered that after 7.3 months of abstinence, individuals with alcohol use disorder (AUD) recover cortical volume comparable to that of healthy individuals. This recovery is significantly accelerated in the first month of abstinence, especially among those who have simultaneously quit smoking. These findings strengthen evidence for the beneficial effects of abstinence and advocate for therapeutic support efforts in this direction.
According to the World Health Organization (WHO), harmful alcohol use results in nearly 3 million deaths worldwide annually, accounting for 5.3% of all deaths. Chronic and abusive alcohol consumption generally leads to AUD, considered a neuropsychological condition characterized by an impaired ability to stop or control alcohol consumption despite awareness of its harmful consequences.
Persistent changes observed in the brain contribute to maintaining AUD and make individuals vulnerable to relapse. These changes include widespread cortical thinning, reflecting a decrease in the number and density of neurons, as well as their connectivity and myelination levels. One affected subregion is the prefrontal cortex, whose impairment hinders planning and decision-making functions.
Previous investigations revealed that abstinence is correlated with a volume increase in several cortical subregions. However, these studies typically focused on the first three months of sobriety and did not sufficiently capture the speed and extent of long-term recovery. The new study, detailed in the specialized journal Alcohol, aims to determine the extent of regional changes in cortical thickness over approximately 7.3 months of sustained abstinence.
A team from Stanford University conducted the study, which involved 45 healthy controls and 88 people with AUD. For the AUD group, brain scans assessing cortical thickness were conducted after 1 week, 1 month, and 7.3 months of abstinence. Measurements were taken for 34 “bilateral interest” cortical subregions supporting various higher-order cognitive functions. Some participants dropped out after one month, with only 40 remaining abstinent until the study’s conclusion. Regarding the control group, scans were performed at the beginning of the study and 9 months later to confirm stable measurements.
Upon analysis, researchers found that participants with AUD exhibited a generalized increase in cortical volume after 7.3 months of abstinence. The volume was statistically significant in 25 of the 34 examined regions and comparable to that of healthy controls in 24 of them. Furthermore, this recovery was particularly accelerated in the first month of abstinence.
Experts also assessed how underlying health issues might influence the level of recovery. Previous research suggested that recovery rates were influenced not only by age and gender but also by medical, psychiatric, substance use-related disorders, and chronic smoking. Individuals with AUD and proatherogenic conditions (hypertension, type 2 diabetes, hepatitis C seropositivity, and/or hyperlipidemia) exhibited greater cortical thinning, indicating these conditions may impede recovery.
The study found that cortical regions thickened more rapidly when smoking participants quit smoking, with a significant level of recovery as early as one week of alcohol abstinence. Conversely, recovery was slowed in AUD individuals who continued to smoke or had high blood pressure or hypercholesterolemia. However, no notable influence was observed for those with psychiatric disorders or a history of smoking.
Nevertheless, these results may not be universally applicable due to the small sample size, and factors such as age and gender were not considered in the analyses. Genetics, physical activity, and liver and lung health could also influence results but were not addressed in the study.
Moreover, the precise effects of these changes on brain functions were not specified. Nevertheless, the data provide clinically relevant information on the beneficial effects of sustained sobriety on human brain morphology, reinforcing the adaptive effects of abstinence-based recovery in AUD, according to the experts in their document.