Effectiveness of a Self-Guided Intervention for Body Dysmorphia and Positive Psychological Outcomes Among Adolescents

## Detailed Description of the Clinical Trial

The primary objective of this clinical trial is to evaluate the effectiveness of a six-week self-guided psychological intervention designed to reduce the symptoms of Body Dysmorphic Disorder (BDD) among adolescents. The study also aims to investigate whether participation in the intervention contributes to improvements in a range of positive psychological outcomes that are associated with mental health, emotional resilience, and overall psychological functioning.

Body Dysmorphic Disorder is characterized by persistent preoccupation with perceived defects or flaws in one's physical appearance that are either unnoticeable or appear minor to others. These concerns often lead to significant emotional distress, repetitive appearance-related behaviors, social withdrawal, reduced quality of life, and impaired psychological functioning. While therapist-led interventions have demonstrated effectiveness in treating BDD, self-guided interventions may offer a more accessible, cost-effective, and scalable approach, particularly for adolescents who face barriers to receiving professional psychological treatment.

This study seeks to determine whether a structured self-guided intervention can effectively reduce body dysmorphic symptoms while simultaneously promoting positive psychological resources and well-being. Rather than focusing solely on symptom reduction, the intervention adopts a positive psychology perspective by examining improvements in psychological strengths and adaptive functioning.

Specifically, the study will assess changes in the following psychological constructs:

• **Self-compassion**, reflecting an individual's ability to respond to personal imperfections and emotional distress with kindness, understanding, and acceptance rather than self-criticism.
• **Gratitude**, representing appreciation for positive experiences and recognition of beneficial aspects of life.
• **Mindfulness**, referring to present-moment awareness accompanied by non-judgmental acceptance of thoughts, emotions, and bodily experiences.
• **Positive affect**, indicating the frequency and intensity of positive emotional experiences such as enthusiasm, happiness, confidence, and optimism.
• **Body satisfaction**, measuring the degree to which adolescents feel satisfied with their overall physical appearance and individual body features.
• **Body esteem**, assessing positive self-evaluations regarding physical appearance, body image, and self-worth related to one's body.
• **Psychological well-being**, encompassing autonomy, environmental mastery, positive interpersonal relationships, personal growth, purpose in life, and self-acceptance.
• **Psychological flexibility**, referring to the ability to remain open to internal experiences while engaging in behaviors that are consistent with personal values and long-term goals.

• Research Questions

The study is designed to address the following research questions:

• Is a six-week self-guided intervention effective in reducing the symptoms of Body Dysmorphic Disorder among adolescents?
• Does participation in the self-guided intervention lead to significant improvements in positive psychological outcomes, including self-compassion, gratitude, mindfulness, positive affect, body satisfaction, body esteem, psychological well-being, and psychological flexibility?
• Are there significant differences between adolescents receiving the self-guided intervention and those in the control group following completion of the intervention?

• Study Design

The research will employ a randomized controlled pretest-posttest experimental design.

Initially, adolescent participants will undergo screening using standardized measures to identify the presence and severity of Body Dysmorphic Disorder symptoms. Individuals meeting the predetermined eligibility criteria will be invited to participate in the study.

Eligible participants will then be randomly assigned to one of two groups:

• **Experimental Group**, which will receive the six-week self-guided intervention.
• **Control Group**, which will not receive the intervention during the study period (or will receive treatment as usual/wait-list control, depending on the study protocol).

Before the intervention begins, participants in both groups will complete a comprehensive battery of psychological assessments measuring Body Dysmorphic Disorder symptoms and all selected positive psychological variables. These baseline assessments will establish participants' initial levels of functioning and serve as the pretest measurements.

Participants assigned to the experimental group will subsequently complete the structured six-week self-guided intervention. The intervention will include evidence-based psychological exercises and activities intended to improve body image, encourage adaptive cognitive and emotional processing, cultivate self-compassion and mindfulness, strengthen gratitude, and promote overall psychological well-being. Participants will complete the intervention independently while following standardized instructions provided by the researchers.

The control group will continue with their usual daily routines without receiving the intervention during the same six-week period.

At the conclusion of the intervention, participants in both the experimental and control groups will again complete the same set of psychological assessments. These posttest measurements will allow researchers to examine changes in Body Dysmorphic Disorder symptoms as well as changes across all positive psychological outcome measures.

### Outcome Evaluation

The effectiveness of the intervention will be evaluated by comparing participants' pretest and posttest scores within each group and between the experimental and control groups. Statistical analyses will determine whether the self-guided intervention produces significant reductions in Body Dysmorphic Disorder symptoms and significant improvements in self-compassion, gratitude, mindfulness, positive affect, body satisfaction, body esteem, psychological well-being, psychological flexibility, and overall psychological functioning.

### Participant Procedure

Participants enrolled in the study will complete the following sequence of activities:

• Undergo screening for symptoms of Body Dysmorphic Disorder using standardized assessment instruments.
• Eligible participants who meet the inclusion criteria will provide informed consent (and parental consent where applicable).
• Participants will be randomly allocated to either the experimental group or the control group.
• All participants will complete baseline (pretest) assessments of Body Dysmorphic Disorder symptoms and all positive psychological outcome measures.
• Participants in the experimental group will complete the six-week self-guided intervention, while participants in the control group will not receive the intervention during this period.
• Following completion of the intervention, both groups will complete the posttest assessments using the same psychological instruments administered at baseline.
• Researchers will compare pretest and posttest scores to determine the effectiveness of the intervention in reducing Body Dysmorphic Disorder symptoms and enhancing positive psychological outcomes.

Inclusion criteria

• Adolescents aged 15 to 18 years
• Male or female participants
• Presence of symptoms of Body Dysmorphic Disorder as indicated by the Body Dysmorphic Disorder Questionnaire (BDDQ)
• Able to read and understand the language in which the study materials and assessment measures are administered
• Willing to participate in the six-week self-guided intervention and complete the required study assessments
• Willing to provide informed assent
• Written informed consent from a parent or legal guardian, where required
• Regular access to the materials required to complete the self-guided intervention

Exclusion criteria

• Participants who do not meet the study screening criteria for symptoms of Body Dysmorphic Disorder
• Current participation in another psychological intervention specifically targeting Body Dysmorphic Disorder or body image concerns
• Current participation in another clinical trial or structured intervention that could affect the study outcomes
• Presence of a severe psychiatric or psychological condition that would interfere with participation in the study or completion of the intervention
• Current suicidal ideation or behavior requiring immediate clinical or psychiatric intervention
• Cognitive, developmental, neurological, or intellectual difficulties that prevent the participant from understanding the study procedures or completing the assessment measures
• Inability or unwillingness to complete the six-week intervention
• Inability or unwillingness to complete the pretest and posttest assessments
• Failure to provide informed assent or parental/legal guardian consent, where required