This study evaluated two psychological interventions for adults with mild to moderate subthreshold anxious-depressive symptoms in primary care in Spain. Participants referred by general practitioners were randomly assigned to either (1) PADAP, a manualized transdiagnostic group program delivered in 10 weekly 90-minute sessions, or (2) a structured active single-session depathologizing intervention (SSDI), delivered individually in one 50-60-minute session.

The primary aim was to compare changes in depressive and anxiety symptoms from baseline to 12 months. Secondary aims included comparing primary care mental health-related consultations, psychotropic medication use, new contacts with mental health services, and perceived need for further mental health care during follow-up.

This was a prospective, parallel-group randomized controlled trial conducted in four primary care health centres in a large urban area in Spain. Adults aged 18-65 years referred by general practitioners for mild to moderate anxious-depressive symptoms were screened for eligibility. Exclusion criteria included meeting DSM-IV Axis I or II criteria based on the Structured Clinical Interview (SCID-I), current active treatment in mental health services, current substance dependence (except nicotine), organic/neurological/cognitive disorders related to symptoms, or language barriers. All participants provided written informed consent, and the study received ethics approval (reference 32/2019 [OE 18/2019]).

Eligible participants were allocated using a centralized, computerized randomization system to one of two intervention arms. Outcome assessment was performed by a blinded assessor. Participants assigned to SSDI received an individual, structured 50-60-minute session focused on empathic listening, contextualization and normalization of distress, narrative reframing, and activation of personal and social resources outside the healthcare system. Participants assigned to PADAP received a manualized, multimodal, transdiagnostic cognitive-behavioral group intervention delivered in 10 weekly 90-minute sessions covering psychoeducation about emotions and skills to manage anxiety, sadness, and anger.

Depressive symptoms were measured with the Beck Depression Inventory (BDI), and anxiety symptoms with the State-Trait Anxiety Inventory (STAI). Assessments were conducted at baseline and at 12 months. Data on primary care consultations for mental health reasons were extracted from electronic health records, along with information on psychotropic medication use and new contacts with mental health services during follow-up.

Inclusion Criteria: 1. Adults aged 18-65 years.

2. Referred from primary care by a general practitioner.

3. Mild to moderate anxious-depressive symptoms based on the GP's clinical judgement during routine consultations, with or without psychotropic medication.

Exclusion Criteria: 1. Meeting DSM-IV Axis I diagnostic criteria based on the Structured Clinical Interview (SCID-I), assessed by two clinical resident psychologists.

2. Receiving active mental health treatment (public or private).

3. Current substance dependence (except nicotine).

4. Organic, neurological, or cognitive disorder related to the symptoms.

5. Language barriers that precluded participation or completion of assessments.

The datasets generated and/or analysed during the current study are not publicly available due to the risk of compromising participant privacy and because they include information derived from electronic health records, but are available from the corresponding author on reasonable request and subject to approval by the relevant data controller/health service.

Outcome assessment at 12 months was performed by assessors blinded to group assignment. Participants and intervention providers were not blinded. Baseline assessment for the SSDI arm was conducted by the clinician delivering the intervention.