Anxiety and Depression subscales of The Brief Symptom Inventory (BSI) include 15 items, each item is rated on a 5-point scale (0 to 4) according to manifestations of anxiety and depression symptoms in the last 30 days (ranging from ''not at-all'' to ''extremely''). Higher scores indicate higher levels of anxiety and depression and worse outcome.

Acceptance and Action Questionnaire assesses psychological inflexibility. It is a 7-item, seven-point Likert-type scale. Scores range between 7 and 49. Higher scores indicate higher levels of psychological inflexibility and worse outcome. The presence of a problem of psychological inflexibility is considered when the score is equal or higher than 27.

Internalized homophobia has been defined as "the internalization of society's homophobic attitudes within a lesbian, gay, or bisexual individual". The Short Internalized Homonegativity Scale measures this phenomenon through a 13-item, five-point Likert-type scale ranging from strongly disagree to strongly agree. Scores range between 13 and 65. Higher scores indicate higher levels of internalized homonegativity and worse outcome. For men, the mean total score is 28.16 (SD = 8.23). The questionnaire includes three sub-scales: public identification as homosexual, sexual comfort with homosexual and social comfort with homosexual people.

The Scale of Evaluation of Social and Emotional Loneliness in Adults evaluates loneliness. The scale is comprised of 3 factors: social loneliness, which reflects the lack of friends and social relationships, family loneliness, which reflects the lack of a supportive family environment for the person, and romantic loneliness, which reflects the lack of an intimate romantic relationship. The scale consists of 15 items with which agreement or disagreement is shown according to a 7-point Likert-type scale. Scores range between 15 and 105. Higher scores indicate higher levels of loneliness and worse outcome.

The Awareness, Courage and Responsiveness Scale is the first measure created to assess a contextual-behavioral model of Intimacy, rooted in the Functional Analytic Psychotherapy. It is a 24-item self-report assessment to evaluate the components of the ACR model, using a 7-point Likert-type scale from 1 (never true) to 7 (always true). The scale is comprised of 4 subscales: Others-Awareness (OA), 5 items; Self-Awareness (SA), 6 items; Courage (C), 6 items; and Responsiveness (R), 7 items. The total sum of the items of the scale is considered a global measure of Intimacy (ACRS-T). Scores range between 24 and 168. Higher scores indicate higher levels of skills to generate intimacy and better outcome.

The Comprehensive Assessment of Acceptance and Commitment Therapy Processes Change is a 23-item, seven-point Likert-type scale. Scores range between 0 and 138. Higher scores indicate higher levels of psychological flexibility and better outcome. This scale provides more accurate information about each of the psychological processes underlying psychological flexibility. Specifically, it consists of 3 subscales: openness, awareness, and action.

The Life Values Questionnaire relates to 10 domains of different life values, which include: family, marriage/intimate partner relationships, parenthood, friendship, work, education, leisure, spirituality, citizenship, and physical self-care. Participants are asked to evaluate on a Likert scale from 0 to 10 the degree of importance they give to these values, where 0 is of little importance and 10 is of great importance. Additionally, they are asked to rate the degree of consistency with which they engage in actions committed to these values, ranging from 0 to 10. Scores are obtained for different sub-scales: importance, consistency, and discrepancy. As a global score for the questionnaire, the composite score is obtained by subtracting the consistency score from the importance score. Higher scores in discrepancy indicates lower levels of value consistency living and worse outcome.

Time spent (hours) planning or practicing sex during last week. Higher number of hours indicate worse outcome.

Self-monitoring: Frequency of practicing chemsex during last week. Higher number of chemsex encounters indicate worse outcome.

Self-monitoring: Number of different sexual partners during last week. Higher number of different sexual partners indicate worse outcome.

Self-monitoring: Frequency of consuming substances during last week. Higher number of substances consumed indicate worse outcome.

Self-monitoring: Frequency of risky sexual practices during the last week. Higher number of risky sexual practices indicate worse outcome.

Self-monitoring: Number of new diagnoses of sexually transmitted infections. Higher number of new diagnoses indicate worse outcome.

Global self-assessment of intensity of cravings Visual Analogue Scale-ratings. Scores range from 0 = very low intensity to 10 = very high intensity. Higher scores indicate higher levels of intensity of cravings and worse outcome

Global self-assessment of interference of cravings Visual Analogue Scale-ratings. Scores range from 0 = very low interference to 10 = very high interference. Higher scores indicate higher levels of interference of cravings and worse outcome.

Self-monitoring: Frequency of value committed actions in presence of craving during last week. Higher number of value committed actions indicate better outcome.