'Flexibility is the name of the game’: Clinicians’ views of optimal dose of psychological interventions for psychosis and paranoia

In the UK, NICE (2014) recommends a minimum of 16 sessions of Cognitive Behaviour Therapy for the treatment of psychosis. One of the barriers to implementation is that clinicians’ views of optimum doses may not fit with this guidance. This study investigates the views of clinicians on the optimal dose of interventions. Fifteen clinicians participated in four focus groups and completed a bespoke questionnaire investigating experiences of dose in different contexts. We used the framework method for data analysis, with Voils et al. (2012) conceptualisation of dose as the frame.

We identified three deductive themes on dose components; number, frequency, and length of therapy sessions. In community settings, participants recommended 1–5 sessions for shorter-term goals, 10–12 sessions for longer-term goals, and highlighted the importance of review after 20–26 sessions. While a range of 16–26 sessions was identified as optimal, a consensus formed around dose being variable to each individual. In inpatient settings, number of sessions was largely dependent on length of stay. In community settings participants found it helpful to initially have weekly sessions and then transition to fortnightly, while in inpatient settings participants met with patients 1–3 times a week. In community settings, participants reported often delivering 50–60 min sessions (although that could vary); while in inpatient settings sessions lasted from 5 min to 2 h. Dose recommendations for community settings applied to digital therapies.

We constructed four inductive themes on how clinicians adapt dose in clinical practice; (1) context matters, (2) individualised treatment approaches, (3) flexibility is key, and (4) balancing clinical idealism and service constraints. Complementing the NICE guidance, our findings endorsed the use of a variable index of sessions to address variability in clinical need. The incorporation of stakeholder views is essential to contextualise quantitative evidence-based recommendations.