This randomised, parallel-group clinical trial evaluates the effects of the Unified Protocol (UP), a transdiagnostic cognitive-behavioural psychotherapy, on dimensional symptom outcomes aligned with the Hierarchical Taxonomy of Psychopathology (HiTOP) and on related temperamental/personality traits in adults with emotional disorders. Participants are randomly assigned (1:1:1) to UP, treatment as usual (TAU), or a waitlist (WL). Outcomes are assessed at baseline and after approximately 14 weeks. A planned follow-up assessment approximately 3 months after treatment completion is collected in the UP arm only.

This study is a single-site, randomised, parallel-group clinical trial conducted in routine outpatient care at the National Institute of Mental Health (NÚDZ), Czech Republic. The trial compares a manualised transdiagnostic cognitive-behavioural intervention (Unified Protocol; UP) with treatment as usual (TAU) and a waitlist (WL) condition in adults with emotional disorders. Participants are screened by telephone and diagnostic eligibility is confirmed using the ADIS-5 prior to randomisation. Randomisation is performed at the individual participant level (1:1:1) using a computer-based randomisation programme. Recruitment and enrolment occur on a rolling basis, contingent on clinical throughput and therapist availability. Assessments are completed at baseline (pre-randomisation) and at post-treatment (approximately 14 weeks) across all study arms. A planned follow-up assessment approximately 3 months after treatment completion is collected in the UP arm only; follow-up participation is voluntary and follow-up completion rates will be reported.

Inclusion Criteria: Adults aged 18-65 years.

Seeking outpatient treatment at NÚDZ for emotional disorder symptoms.

Meets diagnostic eligibility on ADIS-5 for at least one of the following (ICD-10 categories consistent with the protocol): F32, F33, F34, F40, F41, F42, F43, F45, F60, F61.

Able to understand and complete study questionnaires and procedures (Czech language).

Willing and able to participate in psychotherapy and complete assessments at baseline and post-treatment (14 weeks).

If taking psychotropic medication: dose stable for ≥6 weeks prior to enrolment and expected to remain stable during the acute study period where clinically feasible.

Provides written informed consent.

Exclusion Criteria: Current or lifetime psychotic disorder or current manic/hypomanic episode.

High acute suicide risk requiring a higher level of care (e.g., imminent risk, recent serious attempt) or current severe self-harm risk incompatible with outpatient psychotherapy study procedures.

Primary substance use disorder requiring specialised treatment or acute intoxication/withdrawal.

Severe cognitive impairment or neurodevelopmental/neurological condition that prevents valid consent or completion of study procedures.

Concurrent psychological treatment that would conflict with study participation (e.g., starting a new structured psychotherapy during the 14-week study period), unless it constitutes the assigned TAU.

Immediate need for intensive treatment (e.g., inpatient admission) at the time of screening.

Inability to commit to the study schedule or complete required assessments.

This is an open-label behavioural psychotherapy trial. Treatment assignment is not masked to participants or therapists. Questionnaire outcomes are self-reported and collected under pseudonymised study IDs; therapists do not have access to outcome datasets. The data analyst receives a de-identified dataset without direct identifiers.