Khemiri L, Stunckel A, Brynte C, Jayaram-Lindström N
Centre of Psychiatry Research, Department of Clinical Neuroscience,
Karolinska Institutet, Stockholm, Sweden.
Repeated and long-term use of alcohol is known to cause damages in the prefrontal cortex (PFC), a structure of the brain that is responsible for executive functioning. Impairments to the PFC leads to deficits in cognitive functioning such as working memory (WM), impulsivity and emotional regulation, which in turn is known to be one of the underlying factors contributing to increased craving and risk for relapse. Enhancing cognitive functioning in these patients has been proposed as a novel treatment strategy to reduce craving and relapse. 50 patients with alcohol dependence were recruited at an outpatient university clinic. They were randomized to receive 5 weeks of active WM training (n=25) or passive WM training (n=25) using the Cogmed® software. The passive training included identical amount of training sessions but the WM tasks did not increase in difficulty. WM training was performed online at home, and the patients had weekly visits to the clinic to report drinking and craving. Primary outcomes were WM function measured by the Digit Span task and change in percent heavy drinking days (HDD) measured by Timeline Follow-back Interview (TLFB). The active training group had, compared to the passive training group, a significantly greater improvement in Digit Span total score (F (1,48)=5.04;p=0.029), and backward score (F (1,48)=6.27;p=0.016) while no difference was found for forward score (F (1,48)=0.613;p=0.437). The active training group reduced their HDD, based on TLFB data during the study period with 11.4 % compared to 3.4 % in the passive group, but this difference did not reach statistical significance (F (1,47)=1.60;p=0.213). No effect of WM training was found on craving or depression outcomes. The overall finding in this trial is that WM training improves functioning in the PFC in chronic alcohol dependent individuals as evidenced by improvement in WM, while no statistically significant effect was found for drinking outcomes. Our results indicate that WM impairment in alcohol dependent patients can be partially restored through active training. Future studies should evaluate whether WM training as add-on therapy to other treatments targeting drinking behaviour can improve drinking outcomes.