What influences practitioners' readiness to deliver psychological interventions by telephone? A qualitative study of behaviour change using the Theoretical Domains Framework.

Multiple TDF domains emerge as relevant to improve delivery of GSH-T; and these domains are theoretically and practically interlinked. A multicomponent approach is recommended to facilitate the shift from in-person to telephone-based service delivery models, and prompt behaviour change at practitioner, patient and service levels. At a minimum, the development of practitioners' telephone skills, an increase in clients' awareness of telephone-based treatment, dilution of negative preconceptions about telephone treatment, and robust service level guidance and standards for implementation are required. This is the first study that provides clear direction on how to improve telephone delivery and optimise implementation, aligning with current mental health policy and service improvement.