ACT-Enhanced Group Behavior Therapy for Trichotillomania and Skin-Picking Disorder: Feasibility Study Notes

Core Definitions and Clinical Background of TTM and SPD

Trichotillomania (TTM): Characterized by the recurrent pulling of one's hair, resulting in hair loss. It occurs in $1 \% \text{ to } 2 \%$ of the population.
Skin-Picking Disorder (SPD): Characterized by the recurrent picking of one's skin, leading to skin lesions. It also occurs in $1 \% \text{ to } 2 \%$ of the population.
Shared Characteristics: * Both disorders involve highly time-consuming behaviors that individuals often attempt to stop or restrict. * Patients may spend several hours daily pulling or picking and attempting to conceal damage. * Common consequences include clinically significant distress and impaired functioning in social and occupational domains. * Empirical studies show $100 \%$ of TTM participants and $40 \%$ of SPD participants reported social interference. * Occupational interference was reported by $79 \%$ of TTM participants and $35 \%$ of SPD participants. * Shared etiological mechanisms, similar course of illness (puberty onset, chronic waxing/waning), and symptom overlap (premonitory urges followed by relief/pleasure) suggest common treatment pathways.

Rationale for ACT-Enhanced Behavioral Treatment

Limitations of Standard Behavioral Treatments: * Behavioral treatments, primarily Habit Reversal Training (HRT), are superior to most pharmacological options, though N-acetyl cysteine (NAC) shows potential efficacy. * HRT consists of awareness training, competing response training, and stimulus control. * HRT targets repetitive habits but often fails to address intentional behaviors used to avoid unpleasant internal experiences (e.g., anxiety, boredom, or urges).
Experiential Avoidance: This is defined as the phenomenon of escaping private experiences by using maladaptive behaviors. While effective in the short term, it increases the frequency and struggle with avoided events in the long term.
Role of Acceptance and Commitment Therapy (ACT): * ACT-enhanced Behavior Therapy (AEBT) aims to disrupt automatic pulling/picking (out of awareness) and target focused pulling/picking associated with experiential avoidance. * Prior research indicated that a decrease in experiential avoidance significantly correlated with a decrease in TTM severity.
Group Format Advantages: * Increases access for more patients. * Reduces therapist time per patient (cost-effectiveness). * Potentially reduces stigma and shame through peer interaction.

Study Methodology: Participants and Recruitment

Sample Size: $N = 40$ adults. * TTM only: $n = 19$ . * SPD only: $n = 28$ . * Comorbid (both): $n = 7$ .
Inclusion Criteria: Age $\ge 18 \text{ years}$ , primary diagnosis of TTM or SPD per DSM-5, resident of Stockholm County.
Exclusion Criteria: Current substance misuse, lifetime bipolar or psychosis diagnosis, suicidal ideation (MADRS-S score $\ge 4$ on item 10), medication changes within $2 \text{ months}$ , or other concurrent psychological treatment.
Demographics: * Gender: $92 \%$ Female ( $n = 38$ ). * Age: Mean $= 31 \, \text{years}$ ( $SD = 10.6$ ), Range $18 \text{ to } 57 \, \text{years}$ . * Age of Onset: Mean $= 17.5 \, \text{years}$ ( $SD = 10.3$ ), Median $= 15$ . * Education: $55 \%$ High school, $45 \%$ University/College. * Comorbidity: $58 \%$ of participants had at least one additional psychiatric disorder. * ADHD/ADD: $20 \% \, (n = 8)$ . * OCD: $18 \% \, (n = 7)$ . * Major Depressive Disorder: $8 \% \, (n = 3)$ .
Recruitment Source: Referred to ngestenheten (specialist clinic for OCD). Sources included psychiatric clinics ( $54 \%$ ), general practitioners ( $31 \%$ ), dermatologists ( $13 \%$ ), and eating disorder centers ( $3 \%$ ).

Primary and Secondary Assessment Measures

Primary Outcome for TTM: Massachusetts General Hospital Hairpulling Scale (MGH-HPS). * Items: $7$ ; Rating: $0 \text{ to } 4$ ; Total score: $28$ . * Reliability: $r = 0.97$ ; Internal consistency: $\alpha = 0.89$ .
Primary Outcome for SPD: Skin Picking Scale-Revised (SPS-R). * Items: $8$ ; Total score: $32$ . * Internal consistency: $\alpha = 0.83 \text{ (general), } 0.80 \text{ (sample)}$ .
Secondary Outcomes: * Skin Picking Impact Scale (SPIS): social/behavioral/emotional impact ( $10 \text{ items, score 0–50}$ ). * Acceptance and Action Questionnaire-II (AAQ-II) and AAQ-4-TTM: Measures of psychological inflexibility and experiential avoidance. * Sheehan Disability Scale (SDS): Functional impairment. * EQ-5D EuroQol: Quality of life and health status. * MADRS-S and PHQ-9: Depressive symptom tracking. * Clinical Global Impression (CGI-S for Severity, CGI-I for Improvement): Clinician-rated scales from $1 \text{ to } 7$ . * Global Assessment of Functioning (GAF): Clinician-rated functioning.

Overview of the ACT-Enhanced Group Behavior Therapy (AEGBT) Protocol

Treatment Structure: $10 \, \text{weeks}$ of treatment, $10 \, \text{group sessions}$ , plus $5 \, \text{booster sessions}$ at months $1, 2, 3, 6, \text{ and } 12$ .
Session Breakdown: * Session 1: Overview of ACT, psychoeducation, intro to HRT (four components), stimulus control assessment, and self-monitoring. * Session 2: Awareness training (describing pulling/picking and sensations), competing response training, and stimulus control. * Session 3: Values identification and how struggle with urges interferes with those values. * Session 4: Concept of control as the problem, not the solution. * Session 5: Control vs. willingness; introduction of behavioral commitments. * Session 6: Defusion of language (urges/thoughts are not true events); "Embracing the Urge" technique (active practice of willingness). * Sessions 7–10: Continued defusion, acceptance, in-session practice of embracing urges, and individual relapse prevention plans. * Boosters: Problem-solving, in-session practice, and new behavioral commitments.

Statistical Framework and Analysis

Model: Linear mixed effects models used to handle longitudinal data and missing values.
Analysis Principle: Intention-to-treat (ITT) applied to the full sample of $40$ participants.
Correlations: Pearson’s and Spearman’s correlations for symptoms vs. experiential avoidance.
Effect Size: Cohen’s $d$ used for within-group effect sizing.

Treatment Efficacy Results: Primary Outcomes

Posttreatment Significance: Significant reductions in symptom severity were observed for both disorders. * TTM (MGH-HPS): z(19) = 8.36, p < 0.05, d = 0.77. * SPD (SPS-R): z(27) = 10.27, p < 0.001, d = 1.24.
12-Month Follow-up: * SPD symptoms remained significantly reduced: z(27) = 10.07, p < 0.001, d = 0.73. * TTM symptoms did not maintain significant improvement: $z(19) = 10.28, p = 0.672, d = 0.19$ .

Treatment Efficacy Results: Secondary Outcomes and Clinical Significance

Clinicity and Remission: * CGI-I Response: $45 \%$ were responders (much/very much improved) at posttreatment. * Remission (DSM criteria not met): $21 \% \, (n = 4)$ for TTM; $11 \% \, (n = 3)$ for SPD. * TTM clinically significant change (Diefenbach cut-off $\le 6$ ): $21 \%$ at post; $5 \%$ at 12 months. * SPD clinically significant change (SPIS cut-off $\ge 7$ ): $7 \%$ at post; $14 \%$ at 12 months.
Experiential Avoidance (AAQ4TTM): * Significant decrease for TTM: z(19) = 18.75, p < 0.001, d = 0.78. * Significant decrease for SPD: z(28) = 20.30, p < 0.001, d = 1.24. * Correlation with SPD severity: rs = 0.58, p < 0.05. * Correlation with TTM severity: Weak and nonsignificant (rs = 0.33, p > 0.05).
Functioning and Mood: Significant improvements from pre to post on SPIS, MADRS-S ( $d = 0.42$ ), SDS ( $d = 0.39$ ), GAF ( $d = 0.94$ ), and PHQ-9 ( $d = 0.46$ ). Improvements were maintained to $12 \, \text{months}$ .

Treatment Adherence, Feasibility, and Qualitative Feedback

Attrition: $7.5 \% \, (n = 3)$ drop-out rate. Reasons were extrinsic (family conflict, other primary diagnosis, administrative withdrawal due to absence).
Attendance: * Treatment phase: $M = 8.9$ out of $10 \, \text{sessions}$ . * Booster phase: $M = 2.6$ out of $5 \, \text{sessions}$ (attributed to logistic/economic barriers as preventive sickness benefits were unavailable).
Therapeutic Efficiency: Group format (60\, therapist hours for 8\, patients) allowed therapists to see $25 \%$ more patients than an individual format (80\, therapist hours for 8\, patients).
Patient Qualitative Feedback: * Group format reduced shame: "Talking about my hair pulling with others… made me feel less abnormal and crazy." * "Embracing the urge" technique: "…made me less afraid of the impulses and that it gave me a sense of mastery."

Synthesis of Findings and Clinical Discussion

Long-term Maintenance: Maintenance was higher for SPD than TTM. The study suggests skin heals faster than hair grows back, providing quicker visual reinforcement for SPD patients to continue treatment efforts.
Contradictory MGH-HPS Results: While TTM symptom scores (MGH-HPS) returned near baseline at 12 months, clinician ratings (CGI-S, GAF) remained improved. This suggests clinicians considered broader functional improvements beyond just pulling frequency.
Comparison to Prior Studies: Effect size for TTM ( $d = 0.77$ ) was lower than some previous ACT/HRT studies ( $66 \%$ significance in Woods et al. vs $21 \% \text{ to } 53 \%$ depending on definition).

Study Strengths, Limitations, and Directions for Future Research

Strengths: Conducted in routine/ordinary psychiatric care; high recruitment from general referrals; low drop-out rate ( $7.5 \%$ ); included patients with various comorbidities (ADHD/OCD).
Limitations: No control group; small sample size ( $N = 40$ ); lack of control for medication changes; no formal protocol adherence monitoring (supervision).
Future Directions: * Integration of internet-based support between sessions to prevent relapse. * Development of therapist-guided internet behavior therapy to increase geographical accessibility. * Research into stepped-care formats. * Larger randomized controlled trials (RCTs) with active control conditions.

Long-term Maintenance: Maintenance was higher for SPD than TTM. The study suggests skin heals faster than hair grows back, providing quicker visual reinforcement for SPD patients to continue treatment efforts.
Contradictory MGH-HPS Results: While TTM symptom scores (MGH-HPS) returned near baseline at 12 months, clinician ratings (CGI-S, GAF) remained improved. This suggests clinicians considered broader functional improvements beyond just pulling frequency.
Comparison to Prior Studies: Effect size for TTM ( $d = 0.77$ ) was lower than some previous ACT/HRT studies ( $66 \%$ significance in Woods et al. vs $21 \% ext{ to } 53 \%$ depending on definition).