Effectiveness of a Group Intervention Based on Acceptance and Commitment Therapy to Address Problematic Chemsex Through a Randomized Clinical Trial
Phase: NA
Conditions: Hypersexuality, Compulsive Sexual Behavior, Sexualized Drug Use (Chemsex)
Sponsor: Universidad Europea de Madrid

 
 
 
 
 
 
 
Effectiveness of a Group Intervention Based on Acceptance and 
Commitment Therapy to Address Problematic Chemsex Through a 
Randomized Clinical Trial (ChemACT)   
ID: 23.244 
Document date: April 4, 2024 
IP: Francisco Montesinos, Ph.D. 
Study Protocol and Statistical Analysis Plan  
 
 
 

Study Protocol:  
• Objective: To study the effectiveness of an intervention based on 
Acceptance and Commitment Therapy (ACT), applied in patients 
with problematic sexualized use of drugs with high levels of 
hypersexuality. 
• Design: randomized clinical trial 
• Methods:  
After being informed about the study, all patients giving written 
informed consent will be assessed to determine eligibility for study 
entry. Patients who meet eligibility requirements will be assessed 
through a structured interview and standardized questionnaires and 
randomly assigned to two conditions, intervention group and control 
group (waiting list).  
Participants assigned intervention group will immediately receive 
psychological intervention consisting in an 8-session group on line 
ACT-based treatment. The participants will be assessed through self-
report instruments before and after treatment and at 3 months follow-
up. 
Patients assigned to control group condition will remain on the 
waiting list and will receive the intervention after 5 months. 
• Intervention protocol 
• Session 1: Introducing therapy, establishing the therapeutic alliance, 
reframing the problem. Introducing values clarification. Therapeutic 
methods: metaphor "the gym of the mind", metaphor “the garden” 
functional analysis, behavioral experiments. 
• Session 2: Discriminating control as a problem, creative 
hopelessness, introducing acceptance, sustaining work on committed 
actions. Therapeutic methods: metaphor "the hungry tiger", exercise 
"don't think about...". 
• Session 3: Values clarification, identifying barriers related to values 
work, promoting defusion and increasing awareness of private events 
(craving/urge discrimination training), commitment to action. 
Therapeutic methods: funeral exercise, defusion exercise: exposure 
to a complete sequence of an episode of 'out of control' behavior.  
• Session 4: Working on barriers, promoting defusion with thoughts 
related to practicing chemsex (learning to observe thoughts as 
thoughts). Therapeutic methods: metaphor of "the street with shops", 
defusion exercise of "putting thoughts on billboards". 

• Session 5. Acceptance as a choice. Therapeutic methods: metaphor 
of "the toll booth or choosing which train to take", defusion training, 
invitation to choose acting in the presence of emotions, thoughts or 
physical sensations. 
• Session 6. Reinforcing creative hopelessness, establishing the 
perspective of the "self as a context". Therapeutic methods: 
metaphor “walking the path", exercise of the observing self.  
• Session 7. Acceptance, exposure with response prevention to the 
most aversive private events. Therapeutic methods: exercise 
"choosing to pay the toll for a fuller life", invitation to choose acting 
in the presence of aversive private events. 
• Session 8. Relapse prevention. Therapeutic methods: metaphor of 
‘’falling off the bike’’, imaginal exposure to potential situations that 
discriminate inflexible behavior. 
Statistical Analysis Plan (SAP):  
The demographic and clinical characteristics of the participants in each 
treatment group will be described, using measures of central tendency 
(mean, median) and dispersion (standard deviation, range). The results will 
be analysed through non-parametric techniques (comparisons of pre, post 
and follow-up group means). An analysis of variance will be performed to 
determine the specific weight of each independent variable, as well as the 
possible interaction between them. A comparative analysis will be 
conducted between the treatment groups using appropriate statistical tests 
(Student's t-test or Wilcoxon signed-rank test for continuous data, or chi-
square test for categorical data). The statistical approach of Jacobson and 
Truax (1991) will be used to estimate the clinical significance of the effect.