8 Psychotherapy8.4 Service delivery and evaluation in psychotherapy
8.4.3 Psychotherapy outcome studies over time
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Written by Resident Doctor Committee · Published
New in the 2027 syllabus
The College added this topic to the exams from January 2027.
Study designs and the questions they answer
Design | Main question | Common limitation |
|---|---|---|
Randomised trial | Does allocation to the therapy change the outcome? | Selected patients and specialist therapists mean the results may not apply to everyday services |
Pragmatic trial | Does the intervention help in ordinary services? | Delivery and usual care vary, which makes results harder to interpret |
Cohort follow-up | How do outcomes develop after treatment? | Dropout (attrition) and later treatment can explain an apparent change |
Routine service monitoring | Who gets better or worse during care? | With no comparison group, change cannot be put down to therapy alone |
Qualitative study | How do people experience benefit, harm and engagement? | It does not estimate the size of a treatment effect |
Choosing when to measure
Post-treatment outcomes show change by the end of therapy. Follow-up shows whether those gains last, fade or only appear later.
Follow-up timing must match across groups. Studies should be clear whether time counts from allocation or from the end of treatment.
Later treatment and major life events should be recorded, because both can affect longer-term outcomes.
Dropout may remove people who got worse or found treatment unacceptable. Results among those who completed treatment then look better than they really are.
What to measure
Outcomes include symptoms, functioning, quality of life, the patient's own goals, adverse effects and use of other services.
Reliable change is larger than measurement error alone would explain. Clinically meaningful change is an improvement that matters to the patient.
Repeated measurement can show people who are getting worse or have stopped improving, even when the group average looks good.
Long-term follow-up shows that gains persisted only for the period observed. It does not show lifelong benefit.