Memory-Focused Cognitive Therapy for Cocaine Use Disorder: Theory, Procedures and Preliminary Evidence From an External Pilot Randomised Controlled Trial.

BACKGROUND: Cocaine use disorder (CUD) is a debilitating condition with no NICE-recommended medication or specific psychosocial interventions. In the United Kingdom (UK), general counselling (treatment-as-usual; TAU) is widely delivered, but has limited effectiveness. We tested the feasibility, safety and preliminary efficacy of a novel, adjunctive psychosocial intervention for CUD, called 'memory-focused cognitive therapy' (MFCT).

METHODS: We did a two-arm, external pilot randomised controlled trial at a specialist community National Health Service addictions clinic in London, UK. 30 adults (≥18years), voluntarily seeking treatment for CUD (enrolled ≥14days; all with moderate-to-severe DSM5 CUD), were individually randomised (1:1) to a control group (ongoing TAU; 3×90min CUD cognitive conceptualisation assessments; 2×30min cocaine-related cue-induction procedures; and 3×30min research follow-ups); or to an intervention group (ongoing TAU; 3×90min cognitive conceptualisation assessments; 2×30min cocaine-related cue-induction procedures; 5×120min, one-to-one, MFCT sessions [in 1week]; and 3×60min research follow-ups and MFCT-relapse prevention). The primary outcome was the total percentage score on the frequency version of the Craving Experiences Questionnaire (CEQ-F) at 1-month follow-up after the intensive intervention week (clinical endpoint; recall period past 2weeks; higher score indicating greater craving). Secondary outcomes at the 1-month follow-up were percentage days abstinent (PDA) from cocaine, and longest period (days) of continuous abstinence (LPA) in the prior 28days. Outcomes were analysed as an unadjusted group mean difference (with Hedge's g effect size [ES]) and a 95% Confidence Interval [CI] for the primary outcome and a 90% CI for the secondary outcomes. Exploratory, multivariable linear (primary outcome) and Poisson regression models (secondary outcomes), with sex, age, months of regular cocaine use, baseline outcome score, and group estimated the effectiveness of the intervention. The trial is registered with the ISCRTN (ISRCTN16462783).

FINDINGS: Between July 15, 2015, and November 27, 2016, 58 patients were assessed for eligibility and 30 participants were randomised (14 to the control group and 16 to the intervention). With outcome data collected for all participants at the endpoint, the intervention group mean CEQ-F score (14·77; SD 21·47) was lower than the control group mean (51·75; SD 22·72); ES -1·62; 95% CI -2·45 to -0·80. MFCT was associated with more cocaine abstinence in the intervention group (PDA 85·94; SD 18·96) than the control group (PDA 54·59; SD 30·29); ES 1·19; 90% CI 0·54 to 1·84. There was also greater maximum abstinence in the intervention group (LPA 15·69; SD 10·10) than the control group (6·00; SD 7·36); ES 1·06; 90% CI 0·41 to 1·70. Exploratory, confounder-adjusted regression models for this preliminary effect supported the treatment association for reduced craving experiences (CEQ-F Coef. -28·25; 95% CI -45·15 to -11·35); more abstinence (PDA Incidence Rate Ratio [IRR] 1·56; 95% CI 1·31 to 1·88); and greater maximum abstinence (LPA IRR 2·56; 95% CI 1·96 to 3·35), although relative weak unmeasured confounding could overturn these model-adjusted exposure-outcome associations. There were four serious adverse events (among three participants). None were judged related to study procedures or interventions.

INTERPRETATION: In this first external pilot randomised controlled trial of MFCT for CUD, we have shown that the intervention and control procedures and acceptable feasible and safe, and report preliminary evidence that MFCT is associated with reduced craving and increased abstinence. These findings support progression to a substantive trial.

FUNDING SOURCE: UK National Institute for Health Research, Biomedical Research Centre.