Efficacy of Expectancy Focused Exposure Therapy for Anxiety Disorders

Population Description The study sample will consist of adult participants from the general population seeking psychological treatment for anxiety-related problems. Participants will be recruited through multiple sources, including university mental health services, student wellbeing units, community mental health centers, social media advertisements, and other public outreach channels. Recruitment will be intentionally broad to maximize accessibility and ecological validity. Screening and Selection Procedures Eligibility will be determined through a multi-stage screening process. Initial Screening: DSM-5 Cross-Cutting Measures, Levels 1 and 2 Participants responding to recruitment will first complete the DSM-5 Level 1 Cross-Cutting Symptom Measure (APA, 2013; Spanish version APA, 2014). This self-report instrument includes 23 items assessing 13 domains of psychopathology over the past 14 days using a 5-point Likert scale. It has shown good reliability and clinical utility in prior studies (APA, 2014; Bravo et al., 2018). Participants who meet threshold criteria for anxiety-related symptoms on the Level 1 measure will then complete the corresponding DSM-5 Level 2 anxiety measures to further characterize symptom severity. Disorder-Specific Symptom Assessment, Level 3 Participants who meet screening criteria on Levels 1 and 2 will complete disorder-specific symptom scales according to the anxiety disorder suspected or reported, including measures for social anxiety disorder, specific phobia, generalized anxiety disorder, and panic disorder with or without agoraphobia. Diagnostic Assessment Participants who remain eligible after the screening and disorder-specific symptom assessment will undergo a structured clinical interview using the Anxiety and Related Disorders Interview Schedule for DSM-5 (ADIS-5). The ADIS-5 will be used to establish the principal anxiety disorder diagnosis and to assess exclusion criteria, including psychotic disorder, bipolar disorder, high suicide risk, and severe or uncontrolled substance use disorder. Inclusion Criteria: Participants must meet all of the following criteria: * Age between 18 and 70 years. * Seeking treatment for anxiety-related difficulties. * Meet DSM-5 diagnostic criteria for a principal anxiety disorder, including: social anxiety disorder, specific phobia, generalized anxiety disorder, panic disorder with or without agoraphobia. * Diagnosis will be established using the ADIS-5 structured clinical interview. * For participants with generalized anxiety disorder, treatment will focus on the principal anxiety problem identified during assessment. * Present clinically significant anxiety symptoms associated with the principal diagnosis. * If currently taking anxiolytic medication, the dosage must have remained stable for at least three months before the start of treatment and should be maintained during the treatment phase whenever possible. * Willingness and ability to participate in weekly psychotherapy sessions and complete all study assessments. * Provide informed consent. Exclusion Criteria: Participants will be excluded if any of the following conditions are present: * Current psychotic disorder. * Current manic or hypomanic episode, consistent with bipolar disorder. * High suicide risk requiring immediate clinical intervention. * Severe or uncontrolled substance use disorder. * Concurrent participation in psychological treatment specifically targeting the anxiety disorder during the study period. * Medical conditions that contraindicate exposure procedures (e.g., severe cardiovascular conditions). * Cognitive impairment or insufficient language proficiency that would interfere with participation in psychotherapy or completion of assessments.