Compulsive behaviors (e.g., addiction) can be viewed as an aberrant decision process where inflexible reactions automatically evoked by stimuli (habit) take control over decision making to the detriment of a more flexible (goal-oriented) behavioral learning system. These behaviors are thought to arise from learning algorithms known as “model-based” and “model-free” reinforcement learning. Gambling disorder, a form of addiction without the confound of neurotoxic effects of drugs, showed impaired goal-directed control but the way in which problem gamblers (PG) orchestrate model-based and model-free strategies has not been evaluated. Forty-nine PG and 33 healthy participants (CP) completed a two-step sequential choice task for which model-based and model-free learning have distinct and identifiable trial-by-trial learning signatures. The influence of common psychopathological comorbidities on those two forms of learning were investigated. PG showed impaired model-based learning, particularly after unrewarded outcomes. In addition, PG exhibited faster reaction times than CP following unrewarded decisions. Troubled mood, higher impulsivity (i.e., positive and negative urgency) and current and chronic stress reported via questionnaires did not account for those results. These findings demonstrate specific reinforcement learning and decision-making deficits in behavioral addiction that advances our understanding and may be important dimensions for designing effective interventions.

Recent research suggests that graphic motor programs acquired through writing are part of letter representations and contribute to their recognition. Indeed, learning new letter-like shapes through handwriting gave rise to better recognition than learning through typing on a keyboard. However, handwriting and typing do not differ solely by the nature of the motor activity. Handwriting requires a detailed visual analysis in order to reproduce all elements of the target shape. In contrast, typing relies on visual discrimination between graphic forms and does not require such detailed processing. The aim of the present study was to disentangle the respective contribution of visual analysis and graphomotor knowledge. We compared handwriting and typing to learning by composition, a new method which requires a detailed visual analysis of the target without the specific graphomotor activity. Participants composed the target symbols by selecting elementary features from the set displayed on the screen and dragging them in the appropriate position. In four experiments, adult participants learned sets of symbols through handwriting, typing or composition. Recognition tests were administered immediately after the learning phase and again two to three weeks later. Taken together, the results of the four experiments confirm the importance of the detailed visual analysis and provide no evidence for an influence of motor knowledge.

Background: Approximately half of all people with alcohol use disorder (AUD) relapse into alcohol reuse in the next few weeks after a withdrawal treatment. Brain stimulation and cognitive training represent recent forms of complementary interventions in the context of AUD. Objective: To evaluate the clinical efficacy of five sessions of 2 mA bilateral transcranial direct current stimulation (tDCS) for 20 min over the dorsolateral prefrontal cortex (DLPFC) (left cathodal/right anodal) combined with alcohol cue inhibitory control training (ICT) as part of rehabilitation. The secondary outcomes were executive functioning (e.g. response inhibition) and craving intensity, two mechanisms strongly related to abstinence. Methods: A randomized clinical trial with patients (n ¼ 125) with severe AUD at a withdrawal treatment unit. Each patient was randomly assigned to one of four conditions, in a 2 [verum vs. sham tDCS] x 2 [alcohol cue vs. neutral ICT] factorial design. The main outcome of treatment was the abstinence rate after two weeks or more (up to one year). Results: Verum tDCS improved the abstinence rate at the 2-week follow-up compared to the sham condition, independently of the training condition (79.7% [95% CI ¼ 69.8e89.6] vs. 60.7% [95% CI ¼ 48.3 e73.1]; p ¼ .02). A priori contrasts analyses revealed higher abstinence rates for the verum tDCS associated with alcohol cue ICT (86.1% [31/36; 95% CI ¼ 74.6e97.6]) than for the other three conditions (64% [57/89; 95% CI ¼ 54e74]). These positive clinical effects on abstinence did not persist beyond two weeks after the intervention. Neither the reduction of craving nor the improvement in executive control resulted specifically from prefrontal-tDCS and ICT. Conclusions: AUD patients who received tDCS applied to DLPFC showed a significantly higher abstinence rate during the weeks following rehabilitation. When combined with alcohol specific ICT, brain stimulation may provide better clinical outcomes. Trial Registration: ClinicalTrials.gov number NCT03447054 https://clinicaltrials.gov/ct2/show/ NCT03447054.

BackgroundApproximately half the people with alcohol use disorder (AUD) relapse into alcohol reuse in the few weeks following withdrawal treatment. Brain stimulation and cognitive training represent recent forms of complementary interventions in the context of AUD.ObjectiveTo evaluate the clinical efficacy of transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) combined with alcohol cue inhibitory control training (ICT) as part of rehabilitation.MethodsA randomized clinical trial was conducted on patients (n=125) withsevere AUD at a withdrawal treatment unit. Each patient was randomly assigned to one of four conditions, in a 2 [verum vs. sham tDCS] x 2 [alcohol cue vs. neutral ICT] factorial design. The primary outcome of the treatment was the measured abstinence rate after two weeks or more (up to one year).ResultsVerum tDCS improved the abstinence rate at the 2-week follow-up compared to the sham condition, independently of the training condition (79.7% [95% CI = 69.8-89.6] vs. 60.7% [95% CI = 48.3-73.1]; p = 0.02). A priori contrasts analyses revealed higher abstinence rates for the verum tDCS associated with alcohol cue ICT (86.1% [31/36; 95% CI= 74.6-97.6]) than for the other three conditions (64% [57/89; 95% CI = 54-74]). These positive clinical effects on abstinence did not persist beyond two weeks after the intervention.ConclusionsAUD patients who received tDCS applied to DLPFC showed a significantly higher abstinence rate during the weeks following rehabilitation. When combined with alcohol-specific ICT, brain stimulation may provide better clinical outcomes.Trial RegistrationClinicalTrials.gov number NCT03447054

There is a debate over whether actions that resist devaluation (i.e., compulsive alcohol consumption) are primarily habit- or goal-directed. The incentive habit account of compulsive actions has received support from behavioral paradigms and brain imaging. In addition, the self-reported Creature of Habit Scale (COHS) has been proposed to capture inter-individual differences in habitual tendencies. It is subdivided into two dimensions: routine and automaticity. We first considered a French version of this questionnaire for validation, based on a sample of 386 undergraduates. The relationship between two dimensions of habit and the risk of substance use disorder and impulsive personality traits was also investigated. COHS has good psychometric properties with both features of habits positively associated with an Obsessive-Compulsive Inventory score. Besides, the propensity to rely more on routines was associated with lower levels of alcohol abuse and nicotine use, suggesting that some degree of routine might act as a protective factor against substance use. In contrast, a high automaticity score was associated with an increased risk of harmful alcohol use. These results demonstrate that the COHS is a valid measure of habitual tendencies and represents a useful tool for capturing inter-individual variations in drug use problems in undergraduates.