Introduction Despite evidence supporting child and adolescent cognitive behavioural therapy (CBT) globally, interventions remain largely unavailable within public systems. This gap requires implementation models integrating development, training, and scalability research within real-world settings and changes in management structures. Here we developed and implemented manualised psychotherapeutic protocols through a national capacity-building initiative in Greece.

Methods We designed a structured implementation pathway conducted through the Child and Adolescent Mental Health Initiative (CAMHI), a public–private partnership involving clinical and academic institutions across Greece: (1) pre-implementation research through national reviews and national surveys of health professionals; (2) co-development and iterative pilot implementation of evidence-based interventions through supervised practice within the National Health System; and (3) dissemination research supporting scalability and institutionalisation within public structures.

Results Pre-implementation research identified gaps in the availability of clinical protocols in Greek services; a survey of 120 psychologists and psychiatrists indicated the need for psychotherapeutic training. Three evidence-based protocols were co-developed: CBT for anxiety (6–12 years), CBT for depression (12–17 years), and behavioural parent training (BPT) for disruptive behaviour (4–14 years). During a three-stage pilot, 45 clinicians delivered interventions to 140 cases (anxiety n=52; depression n=25; BPT n=63); 117 (83·5%) completed treatment. Significant symptom reductions were observed for anxiety (d=−2·92; RCADS-25), depression (d=−1·79, RCADS-25), and disruptive behaviour (d=−2·3, SNAP-IV), with 63%, 38% and 44% showing reliable improvement at the treatment endpoint. A train-the-trainer model is under implementation for national scale-up. Institutionalisation includes integration into child and adolescent psychiatry curricula. Sustainability safeguards were established through Law 5015/2023, with the Ministry of Health assuming operations by 2027.

Discussion Pilot results demonstrate the feasibility of evidence-based psychotherapeutic interventions embedded within real-world child and adolescent services in Greece. Integrated implementation approaches provide a viable pathway for developing, refining, and scaling clinical manuals within public health provision.

The authors have declared no competing interest.

This study was funded by the Stavros-Niarchos Foundation (SNF) as part of the Child and Adolescent Mental Health Initiative (CAMHI) in Greece

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Each regional hub secured ethical approval from its respective local ethics board, with amendments approved as necessary to accommodate additional trainers. In Athens, approvals were granted by the 1st Health District of Attica via the Scientific Council of "Agia Sofia" Children's General Hospital (27761/04.12.2023; 20381/12.08.2024). In Thessaloniki, approval was obtained from the 3rd Health District of Macedonia through the Scientific Councils of Hippokrateio Hospital (52297/17.11.2023) and Papanikolaou Hospital (925/28.11.2023; 1218/10.09.2024). Approval for the Ioannina hub was provided by the Administrative Board of the University General Hospital of Ioannina (36/19.12.2023). In Crete, the 7th Health District granted approval through the Scientific Council of the University General Hospital of Heraklion (36515/31.10.2023). Finally, in Alexandroupolis, approvals were issued by the Administrative Board of the University General Hospital of Alexandroupolis (54805/09.11.2023; 55388/04.11.2024).

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Conflicts of interest: Authors report no conflicting interests.

Funding: The Child and Adolescent Mental Health Initiative (CAMHI) in Greece is exclusively supported by the Stavros-Niarchos Foundation (SNF).

All data produced in the present study are available upon reasonable request to the authors