Memory biases in alcohol use disorder: enhanced memory for contexts associated with alcohol prospectively predicts alcohol use outcomes

Abstract

Memory for prior drinking experiences may powerfully drive later alcohol use in familiar drinking contexts, yet we know little about what patients with alcohol use disorder (AUD) remember of alcohol-related episodes. Although animal and theoretical models of addiction emphasize the importance of different memory systems for understanding maladaptive use, clinical research parsing what AUD patients remember from alcohol-related episodes is lacking. The current study applied a novel memory task in which moderate drinkers (N = 30) and treatment-seeking individuals with alcohol use disorder (AUD: N = 29) encoded associations between photographs of objects (alcoholic beverages and neutral items) and photographs of neutral scenes. At least 24 h later, two types of memory were assessed: item memory (object recognition) and associative memory (cued recognition of scenes associated with objects). To assess which memories predicted drinking, real-world behavior was assessed in patients with AUD at baseline and for 4 weeks following memory tests. Despite demographic differences, the results showed broadly impaired item memory in AUD compared with moderate drinkers (p < 0.001), but enhanced associative memory for scenes paired with alcohol (p = 0.015). These associative memory biases were especially pronounced for stimuli rated as more affectively salient. Furthermore, stronger but less detailed memory for alcohol-related associations (i.e., choosing the correct scene but the incorrect photograph) significantly predicted heavier baseline (p = 0.002) and higher subsequent (p = 0.01) drinking in patients with AUD. These findings reveal a novel alcohol-related memory bias in AUD, and uncover the importance of associative memory for understanding real-world heavy alcohol use.

Fig. 1. Design and subjective responses during encoding.

a Procedure. Participants first completed intake assessments, in which baseline real-world drinking behavior (over the previous week) was assessed in patients with alcohol use disorder (AUD). Next, participants completed two blocks of object/scene encoding with alcoholic beverages or neutral objects. Cue order (alcohol vs. neutral objects) was counterbalanced across participants. After a delay, they were tested for their memory for the individual items and their associated scenes. Finally, patients with AUD were tracked for 4 weeks to assess prospective real-world drinking behavior. b Task design. During encoding, participants vividly associated unique pairs of objects and scenes. Ratings of subjective responses were assessed for every trial. During the item memory test, recognition of individual objects (plus content-matched foils) was assessed. During the associative memory test, participants were asked to recall whether the scene paired with the object was indoor or outdoor, and then to select the scene from a list of photographs. These photographs contained the exact image seen during encoding (specific associative memory), and an image portraying the same type of scene, but a different photograph (gist associative memory). c Examples of alcohol-related objects (red border, left) and neutral objects (gray border, right). d Subjective ratings during encoding for object/scene pairs containing alcohol (red) or neutral objects (gray). MOD moderate drinkers, AUD patients with alcohol use disorder. Error bars = +/−1 SE.

Fig. 2. Drinking history influences item and associative memory for alcohol cues.

a Patients with alcohol use disorder (AUD) had significantly worse item memory than moderate drinkers (MOD). b Distinct effects of alcohol cues on associative memory in moderate drinkers and patients with AUD. Left, specific (detailed) memory for alcohol-related associations is impaired in moderate drinkers, but spared in patients with AUD. Right, moderate drinkers show less detailed “gist”-level memory for alcohol-related associations, whereas patients with AUD show less detailed memory for associations with neutral objects. *p < 0.05; **p < 0.01; ***p < 0.001.

Fig. 3. Affective responses to alcohol drive memory biases.

a Density plots of arousal and craving ratings for trials containing photographs of the top-ranked alcoholic beverage. We computed affective responses per alcoholic beverage (weighted sum of arousal and craving with penalty for rating trials as neutral), and separated trials including the highest-ranked alcoholic beverage (“top-ranked alcohol”) from other alcohol and neutral object trials. b Item memory separated by drinking group and alcohol ratings, showing better item memory for more salient alcohol items. c Associative memory (specific) separated by drinking group and alcohol ratings. More salient alcohol items led to worse associative memory in moderate drinkers (MOD), but better associative memory in patients with alcohol use disorder (AUD). Gray bars (neutral objects) reproduced from Fig. 2c. Error bars = ±1 SE. *p < 0.05, **p < 0.01.

Fig. 4. Gist-level associative memory for alcohol predicts real-world drinking behavior.

a Baseline drinking behavior (1 week prior to start of the study). b Subsequent drinking behavior (4 weeks following memory assessment during treatment). Distribution of average reported drinking behavior at each time point shown at the left for reference. Relationships between drinking behavior and normalized item memory (middle) and associative memory (right) are shown, separately for alcoholic beverages (red) and neutral objects (gray). In each plot, participants are represented by two dots: one for alcohol-related and one for neutral object-related memories. Error bars = standard error of model coefficients.