Acute impact of self-guided mental imagery on craving in cocaine use disorder: a mixed-methods analysis of a randomized controlled trial

Abstract

Mental imagery manipulations are used to treat several psychological disorders, but their utility in treating cocaine use disorder (CUD) is unknown. Using prompted re-experiences and simulations with contrasting valence, we assessed the acute impact of a deliberate mental imagery task on cocaine craving.

Design: A quantitative-qualitative 'mixed-methods' analysis of data collected for a randomized controlled trial that was stopped prematurely.

Setting: UK National Health Service addictions treatment clinic and outpatient clinical research facility (laboratory).

Participants: Adults with CUD. The original target sample was 120. All participants enrolled at the point the original trial was stopped were included (38 enrolled, 31 completed study).

Interventions: Personalized (3-minute) cue-exposure (handling cocaine paraphernalia and watching video of drug preparation), immediately followed by a single 5-minute, audio-recorded, self-guided and verbally described imagery task with random assignment to one of four conditions: two mental imagery memory re-experiences (positive image before initiation to cocaine use or a negative image of a 'worst time' adverse cocaine use episode) or two future simulations (positive theme of recovery from CUD or negative theme of worsened CUD).

Measurements: Task transcripts were rated for imagery detail using five dimensions using a six-point scale of imagery detail (ID) (total score = 0-25) and thematically coded. The outcome measure was cocaine craving using the Craving Experiences Questionnaire-strengths version (CEQ-S11; score = 0-110) reported at baseline, arrival at the laboratory, and immediately after the cue-exposure and mental imagery tasks.

Findings: A mixed-effects, longitudinal, restricted linear regression, with the past-positive imagery condition as referent, showed main effects of reduced craving after the imagery task (b = -29.2, 95% confidence interval (CI) = -45.3 to -13.1, P-value < 0.001) and increased craving for the future-negative task (b = 14.2, 95% CI = 0.1-28.4, P-value 0.049). There was a future-negative task by post-imagery craving interaction (b = 28.1, 95% CI = 0.1-56.1, P-value 0.049). A theory-driven, deductive/inductive qualitative analysis of the transcripts revealed six major themes: sensory characteristics, CUD vicious cycle, self-care, emotions and appraisals, social role and CUD recovery. Positively themed simulations included interpersonal connections and rewarding activity; negative images included personal adversity, with appraisals of self-criticism and hopelessness. Transcripts with more imagery detail were not associated with significantly greater reductions in craving in the positive or negative imagery task (r = -0.32, 95% CI = -0.69 to 0.13 and r = 0.06, 95% CI = -0.58 to 0.53, respectively).

Conclusion: In people with cocaine use disorder, after cue-exposure, a self-guided imagery task with positive themes reduced craving, whereas mental imagery simulating worsened cocaine use disorder did not appear to.

Keywords: cocaine use disorder; cognitive behavioural therapy; cognitive therapy; craving; cue-exposure; mental imagery.