A pragmatic, 4-week, 4-group, between-subjects, factorial randomised controlled trial conducted at a specialist NHS outpatient addictions clinic and hospital clinical research facility to determine if mental imagery (of past and future positive \[recovery oriented\] and negative \[cocaine aversive\] events) can help reduce cue-induced cocaine craving and cocaine use.
Cocaine, a powerful stimulant drug, is used by 2.2% of people aged 16-59 in England and each year about 150.000 people seek help for cocaine use disorder from the NHS or non-governmental organisations (NGO). There are currently no approved medication-assisted treatments or specific psychosocial interventions for CUD. General counselling is offered by the NHS and NGO addiction services, but this is not particularly effective. The transition from regular cocaine use to cocaine abuse is often marked by intense episodes (binges), which may last several days and are followed by a 'crash' with no or little use. For many people, repeated administration of cocaine over a short duration of time creates vivid episodic memories of euphoria which can inform future craving content. Craving or strong urges are a distinctive feature of CUD and are often reported as involuntary, distressing and uncontrollable. Research has demonstrated that craving experiences can be voluntarily evoked or elicited by conditioned drug cues in the environment and internal processes such mood or physical sensations. The associations between cues and use are established through classical and instrumental reward-based conditioning and are important for the development and maintenance of CUD. Enhanced attention to cocaine cues develops and remains heightened for at least six months into abstinence. Craving-related experiences are informed by memories of intense reward, physical sensations and include pro-drug beliefs, appraisals, expectancies and vivid mental imagery. Drug-imagery is often initially pleasurable and affectively charged and can motivate drug-seeking behaviour. If impeded or delayed, drug imagery highlights a deficit and can be experienced as distressing and intrusive. Treatment of intrusive images has been successful in various psychological disorders using imagery rescripting. Imagery rescripting has recently been used in memory-focused cognitive therapy to help reduce cocaine craving. Reducing intrusive image-induced negative affect through positive imagery is important for relieving psychological distress but there is also evidence that aversive imagery may reduce maladaptive approach behaviours. This will be a pragmatic, 4-week, 2x2, between-subjects, factorial randomised controlled trial. It will be conducted at a specialist NHS outpatient addictions clinic (Lorraine Hewitt House; LHH) operated by South London and Maudsley NHS Foundation trust (SLaM) and at the NIHR Wellcome Trust King's Clinical Research Facility (CRF) at King's College Hospital. Informed consenting adult participants will be randomised to one of four conditions: * future-based (prospective) recovery-oriented imagery; * future-based (prospective) cocaine-aversive imagery; * past (autobiographical) recovery-oriented imagery; or * past (autobiographical) cocaine-aversive imagery. Participants will undergo a craving induction procedure designed to elicit cue-induced craving. In response to elevated craving, participants will be asked to reduce their craving levels using a mental imagery intervention. Following the procedure in the research facility, participants will be given a digital audio player to take home. This will contain a recording of the imagery condition they are allocated to. Participants will be asked to listen to this recording each day during a 14-day follow-up, and ad libertatem when experiencing cocaine craving. After 14 days participants will be invited for a follow up conducted at the community addictions clinic.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
120
a behavioural mental imagery intervention where participants are asked to generate specific mental images to reduce cue-induced craving for cocaine use disorder
Lorraine Hewitt House
London, United Kingdom
RECRUITINGChanges in Number of Days abstinent from Cocaine
The primary outcome measure will be number of days abstinent from cocaine (percentage). A higher percentage indicates a higher number of abstinent days from cocaine. This will be expressed as the cumulative distribution function for change (between baseline and follow-up) using a Timeline Follow Back method (calendar prompt). Percentage days abstinent is measured for two weeks before the first assessment and two weeks post craving-induction procedure.
Time frame: baseline (Week 0) and at two week-follow up (Week 4)
Change from baseline in Craving Experience Questionnaire Score (CEQ-12)
The CEQ-12 is an 12-item, self-report instrument measuring intensity, imagery and intrusiveness dimensions of craving. Each item is rated on a 11-point scale (0-10), ranging from 0-120, where a higher score expresses increased craving. The intensity subscale ranges from 0 to 30 where 30 indicates a constant urge to use cocaine. The imagery subscale ranges from 0 to 60 where 60 indicates a constant sensory craving experience The intrusiveness subscale ranges from 0 to 30 where 30 indicates constant intrusive thoughts about cocaine The CEQ-12 is measured at baseline (craving for past 2 weeks) and at two week-follow up (craving for past two weeks) The total craving score will be expressed as cumulative distribution function for change in cocaine craving.
Time frame: baseline (Week 0) and at two week-follow up (Week 4)
Urine toxicology Screening (UDS)
By instant result immunoassay device for cocaine metabolite (benzoylecgonine) and morphine (Alere Toxicology).
Time frame: Assessed at two-week follow up (Week 4)
Imagery Monitoring Diary
A monitoring diary used by participants to indicate use of guided imagery audio and changes in craving levels. Diary will be used daily throughout 14-day follow-up period.
Time frame: Diary assessed at two-week follow up (Week 4)
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Heart Rate Variability (HRV)
Real-time HRV data will be acquired through an E4 Empatica (www.empatica.com) wristband placed on the participants' wrist during the craving induction procedure and imagery intervention conducted at the clinical research facility. the HRV is derived from blood volume pulse and will be computed using the mean differences and peak values of the parameters.
Time frame: Week 2; 2 hour session
Electrodermal Activity (EDA)
Real-time EDA data will be acquired through an E4 Empatica (www.empatica.com) wristband placed on the participants' wrist during the craving induction procedure and imagery intervention conducted at the clinical research facility. the EDA will be computed using the mean differences and peak values of the parameters.
Time frame: Week 2; 2 hour session
Temperature
Real-time EDA data will be acquired through an E4 Empatica (www.empatica.com) wristband placed on the participants' wrist during the craving induction procedure and imagery intervention conducted at the clinical research facility. the EDA will be computed using the mean differences and peak values of the parameters.
Time frame: Week 2; 2 hour session
Episodic Foresight Score (EFS)
based on the Adapted Autobiographical Interview (AI (Levine et al. 2002; adapted version, Addis, Wong and Schacter (2008)); adapted for this study. The Episodic foresight score (EFS) provides an index of the extent to which participants are personally experiencing an event during mental imagining. This translates into episodic foresight capabilities. EFS is derived from transcribed mental image descriptions. Details are segmented and categorised as either internal or external. The number of internal details provided an index of the extent to which participants are personally experiencing the event during mental imagining. High score of external details/ Low score of internal detail signify limited episodic foresight whereas a low score of external detail/high score of internal detail signifies good episodic foresight.
Time frame: EFS is assessed during the assessment session (Week 1)
Substance Related Imagery Semi Structured Interview (SRI)
A semi structured interview examining intrusive imagery in substance use. This interview will be used to explore individual craving experiences and help prepare the participant for the imagery intervention. Consists of 21 questions exploring imagery in substance use. These are divided into three sections: Exploring Substance Related Images, Link to memories and Negative Valence Imagery. Interview consists of a mix of open-ended questions, visual analogue scales and Yes/No questions. The interview schedule will be used during the craving experiences interview in the stage 1 assessment.
Time frame: Week 1 (Assessment)
Predominance of verbal and imagery-based thoughts visual analogue scale (PV-IT)
Consists of two rating questions to assess the use of imagery versus verbal thought; 'How much of the time has your thinking taken the form of verbal thoughts over the past 5 minutes?', 'How much of the time has your thinking taken the form of mental imagery over the past 5 minutes?', along with two analogue scales ranging from 'none of the time' to 'all of the time', from 0-9 where 9 indicates all of the time. A higher score indicates frequency of thought in either a visual or verbal modality. Scale will be administered post craving induction procedure and post imagery intervention.
Time frame: Week 2 ( x2; Post Craving Induction; Post Imagery Intervention)
The Positive and Negative affect Schedule (PANAS)
A self-report questionnaire to measure positive and negative affect. The PANAS consists of 20 different affect-related words. Participants indicate if and to what extent they experience the described feeling at the moment of filling in the questionnaire. The scale ranges from 1-5, where 5 indicates a strong experience of a feeling whereas 1 indicates very slightly or not at all. The PANAS provides two scores, one for negative affect and one for positive affect, where higher scores indicate higher levels of negative and positive affect respectively. The PANAS will be administered post imagery intervention.
Time frame: Week 2 ( Post Imagery Intervention)
Obsessive Compulsive Drug Use Scale (OCDUS)
A self-report questionnaire to measure craving with a focus on the intrusive, obsessive and compulsive characteristics associated to cocaine craving and use. The OCDUS has 12 questions rated on a 1-5 Likert Scale and is divided into three subscales: Cocaine Thoughts and Interference (six items), Desire and Control (four items); Resistance to Thoughts and Intention (two items). High scores indicate high levels of cocaine thoughts and interference, high levels of desire and low control over cocaine use and low levels of resistance to cocaine thoughts. Questionnaire will be administered during Stage 1 assessment.
Time frame: Week 1 ( Assessment)
Patient Health Questionnaire (PHQ-9)
A self-administered questionnaire to assess depression severity using the DSM-IV depression criteria. The PHQ-9 consists of 9 items rated on a 4 point scale ( 0-3). The PHQ-9 explores the frequency of problems over the last two weeks where 0 is not at all and 3 is nearly every day. The total score indicates depression severity as follows: 0-4 none, 5-9 mild, 10-14 moderate, 15-19 moderately severe, 20-27 severe. Questionnaire will be administered during Stage 1 assessment.
Time frame: Week 1 (Assessment)
Generalised Anxiety Disorder Assessment (GAD-7)
A self-administered questionnaire to assess general anxiety disorder (GAD) using the DSM-IV criteria. The GAD-7 consists of 7 items rated on a 4 point scale ( 0-3). The GAD-7 explores the frequency of problems over the last two weeks where 0 is not at all and 3 is nearly every day. The total score (0-21) indicates anxiety severity as follows: : 0-5 mild 6-10 moderate 11-15 moderately severe anxiety ;15-21 severe anxiety. Questionnaire will be administered during Stage 1 assessment.
Time frame: Week 1 (Assessment)