About this trial
This prospective observational study follows adults undergoing residential rehabilitation for severe substance use disorders at a specialized treatment center in Mexico. Participants provide weekly written narratives describing their emotions, challenges, coping strategies, and treatment experiences, and complete validated psychological questionnaires every two weeks, including the Generalized Anxiety Disorder-7 (GAD-7), Environmental Reward Observation Scale (EROS), Automatic Thoughts Questionnaire-8 (ATQ-8), and Behavioral Activation for Depression Scale (BADS).
The study applies natural language processing (NLP) and machine learning methods to analyze participants' narratives and identify emotional, cognitive, and behavioral patterns associated with clinical change over time. Narrative-derived features are combined with questionnaire scores to generate a dynamic clinical risk representation that may help detect early signs of psychological worsening or improvement during residential treatment.
Participants continue receiving standard residential care, and the study does not modify treatment decisions or clinical interventions. Up to 35 participants with sufficient longitudinal follow-up data will be included in the primary analysis. Data collection is expected to continue through September 2026.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Clinical diagnosis of severe substance use disorder (polydrug use, including cocaine, methamphetamines, alcohol, and/or cannabis), confirmed by the center's admission assessment.
Male sex (all participants in the center's residential program are male).
Age 18 years or older.
Current resident of the participating residential rehabilitation center in Mexico.
Disqualifiers
Presence of acute psychotic symptoms that interfere with the ability to write or understand the study procedures.
Severe cognitive impairment (e.g., due to traumatic brain injury, intellectual disability) that prevents meaningful narrative production.
Inability to comply with weekly narrative writing (e.g., illiteracy, severe visual impairment).
Planned discharge from the residential program within less than 4 weeks from enrollment.
Trial population
Adult males (≥18 years) with severe substance use disorder, residing in a single residential rehabilitation center in Mexico. Participants are enrolled consecutively as they enter the program and meet eligibility criteria. The sample is non-probabilistic, reflecting the real-world clinical population of this specific center.
Trial design
Cohort
Prospective
Treatments tested in this trial
Residential rehabilitation as usual
Other interventionParticipants follow the standard residential rehabilitation program provided by the center. This is a naturalistic exposure; the study does not impose any additional intervention. The "intervention" of interest is the routine therapeutic environment and its associated psychological processes (e.g., changes in avoidance, cognitive fusion, hope, and behavioral activation). These processes are measured through weekly written narratives and biweekly validated clinical scales (GAD-7, EROS, ATQ-8, BADS).
Treatment groups
Trial outcomes
Primary outcomes
Change in negative automatic thoughts measured by the Automatic Thoughts Questionnaire 8-item version
The Automatic Thoughts Questionnaire 8-item version is administered every two weeks. Total scores range from 8 to 40, with higher scores indicating more frequent negative automatic thoughts. The primary outcome is the change from baseline in total score over the course of residential treatment.
Secondary outcomes
Change in generalized anxiety symptoms measured by the Generalized Anxiety Disorder 7 item scale
The Generalized Anxiety Disorder 7-item scale is administered every two weeks. Total scores range from 0 to 21, with higher scores indicating greater anxiety symptom severity.
Change in environmental reward measured by the Environmental Reward Observation Scale
The Environmental Reward Observation Scale iis administered every two weeks. Total scores range from 10 to 40, with higher scores indicating greater exposure to positive environmental reinforcement.
Change in behavioral activation and avoidance measured by the Behavioral Activation for Depression Scale
The Behavioral Activation for Depression Scale is administered every two weeks. Higher scores on the Activation subscale indicate greater engagement in goal-directed activity; higher scores on the Avoidance/Rumination subscale indicate greater behavioral avoidance and rumination.
Weekly self-reported emotional intensity
Participants report the intensity of their predominant weekly emotion on a 0 to 10 numeric rating scale, where higher scores indicate greater emotional intensity.
Other outcomes
Narrative sentiment valence index derived from weekly written narratives
Sentiment valence is calculated from weekly written narratives using a validated Spanish-language sentiment classification model. Scores range from -1 to +1, with lower scores indicating more negative emotional valence.
Semantic similarity to Acceptance and Commitment Therapy-related constructs
Semantic similarity scores are computed between weekly narratives and prototype domains (e.g., experiential avoidance, cognitive fusion) using sentence embedding methods. Scores range from 0 to 1 (higher = greater similarity).
Composite Clinical Risk Index derived from longitudinal narrative features
A composite longitudinal risk score is a composite longitudinal risk score calculated using multiple narrative-derived emotional variability indicators. Higher scores indicate greater estimated clinical vulnerability over time.
Linguistic markers extracted from weekly written narratives
Linguistic variables including lexical diversity (type-token ratio), first-person pronoun frequency, and past-tense verb proportion are extracted from weekly written narratives using automated natural language processing (NLP) procedures.
Sponsors and contacts
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Lauro Gutiérrez Castro
Lead sponsor
Under The Tree Therapeutic Community
Sponsor institution