The dose-response effect refers to the relationship between the dose (e.g., length, frequency) of treatment and the subsequent probability of improvement. This systematic review aimed to synthesise the literature on the dose-response effect in routine psychological therapies delivered to adult patients with mental health problems. Twenty-six studies were eligible for inclusion. Different methodological approaches have been used to examine the dose-response effect; including survival analysis, multilevel modelling and descriptive cluster analyses.Replicated and consistent support was found for a curvilinear (log-linear or cubic) relationship between treatment length and outcomes, with few exceptions such as eating disorders and severe psychiatric populations. Optimal doses of psychotherapy in routine settings range between 4 -26 sessions (4 -6 for low intensity guided self-help) and vary according to setting, clinical population and outcome measures. Weekly therapy appears to accelerate the rate of improvement compared to less frequent schedules. Most of the reviewed evidence is from university counselling centres and outpatient psychotherapy clinics for common mental health problems. There is scarce and inconclusive evidence in clinical samples with chronic and severe mental disorders.

Background Cognitive‐behavioral therapy (CBT) is effective for the treatment of common mental health problems, but the number of sessions required to maximize improvement in routine care remains unclear. Aim This study aimed to examine the dose‐response effect in low (LiCBT) and high (HiCBT) intensity CBT delivered in stepped care services. Methods A multi‐service data set included N = 102 206 patients across N = 16 services. The study included patients with case‐level depression and/or anxiety symptoms who accessed LiCBT and/or HiCBT. Patients with posttreatment reliable and clinically significant improvement in standardized outcome measures (PHQ‐9, GAD‐7) were classified as treatment responders. Survival analyses assessed the number of sessions necessary to detect 50%, 75%, and 95% of treatment responders. The 50% and 95% percentiles were used to define the lower and upper boundaries of an adequate dose of therapy that could be used to inform the timing of treatment progress reviews. Analyses were then stratified by diagnosis, and cox regression was used to identify predictors of time‐to‐remission. Results Most responders (95%) attained RCSI within 7 sessions of LiCBT and 14 sessions of HiCBT. Patients with social anxiety disorder, posttraumatic stress disorder, and obsessive‐compulsive disorder required HiCBT and lengthier treatments (6–16 sessions) to maximize improvement. Conclusions Distinctive dose‐response patterns are evident for LiCBT and HiCBT, which can be used to support treatment planning and routine outcome monitoring.

Background Preventative medication reduces hospitalisations in people with cystic fibrosis (PWCF) but adherence is poor. We assessed the feasibility of a randomised controlled trial of a complex intervention, which combines display of real time adherence data and behaviour change techniques. Methods Design: Pilot, open-label, parallel-group RCT with concurrent semi-structured interviews. Participants: PWCF at two Cystic Fibrosis (CF) units. Eligible: aged 16 or older; on the CF registry. Ineligible: post-lung transplant or on the active list; unable to consent; using dry powder inhalers. Interventions: Central randomisation on a 1:1 allocation to: (1) intervention, linking nebuliser use with data recording and transfer capability to a software platform, and behavioural strategies to support self-management delivered by trained interventionists ( n = 32); or, (2) control, typically face-to-face meetings every 3 months with CF team ( n = 32). Outcomes: RCT feasibility defined as: recruitment of ≥ 48 participants (75% of target) in four months (pilot primary outcome); valid exacerbation data available for ≥ 85% of those randomised (future RCT primary outcome); change in % medication adherence; FEV 1 percent predicted (key secondaries in future RCT); and perceptions of trial procedures, in semi-structured interviews with intervention ( n = 14) and control ( n = 5) participants, interventionists ( n = 3) and CF team members ( n = 5). Results The pilot trial recruited to target, randomising 33 to intervention and 31 to control in the four-month period, June–September 2016. At study completion (30th April 2017), 60 (94%; Intervention = 32, Control =28) participants contributed good quality exacerbation data (intervention: 35 exacerbations; control: 25 exacerbation). The mean change in adherence and baseline-adjusted FEV 1 percent predicted were higher in the intervention arm by 10% (95% CI: -5.2 to 25.2) and 5% (95% CI -2 to 12%) respectively. Five serious adverse events occurred, none related to the intervention. The mean change in adherence was 10% (95% CI: -5.2 to 25.2), greater in the intervention arm. Interventionists delivered insufficient numbers of review sessions due to concentration on participant recruitment. This left interventionists insufficient time for key intervention procedures. A total of 10 key changes that were made to RCT procedures are summarised. Conclusions With improved research processes and lower monthly participant recruitment targets, a full-scale trial is feasible. Trial registration ISRCTN13076797...

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ObjectivesTo undertake a process evaluation of an adherence support intervention for people with cystic fibrosis (PWCF), to assess its feasibility and acceptability.SettingTwo UK cystic fibrosis (CF) units.ParticipantsFourteen adult PWCF; three professionals delivering adherence support (‘interventionists’); five multi-disciplinary CF team members.InterventionsNebuliser with data recording and transfer capability, linked to a software platform, and strategies to support adherence to nebulised treatments facilitated by interventionists over 5 months (± 1 month).Primary and secondary measuresFeasibility and acceptability of the intervention, assessed through semistructured interviews, questionnaires, fidelity assessments and click analytics.ResultsInterventionists were complimentary about the intervention and training. Key barriers to intervention feasibility and acceptability were identified. Interventionists had difficulty finding clinic space and time in normal working hours to conduct review visits. As a result, fewer than expected intervention visits were conducted and interviews indicated this may explain low adherence in some intervention arm participants. Adherence levels appeared to be >100% for some patients, due to inaccurate prescription data, particularly in patients with complex treatment regimens. Flatlines in adherence data at the start of the study were linked to device connectivity problems. Content and delivery quality fidelity were 100% and 60%–92%, respectively, indicating that interventionists needed to focus more on intervention ‘active ingredients’ during sessions.ConclusionsThe process evaluation led to 14 key changes to intervention procedures to overcome barriers to intervention success. With the identified changes, it is feasible and acceptable to support medication adherence with this intervention.Trial registration numberISRCTN13076797; Results.