Why it is important to watch every session: the ‘antibiotic effect’.

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To get the best out of the course, it is important to watch every session and watch them in sequence. We know this from independent research carried out by Sheffield University and the NHS in Sheffield*.

Sheffield looked at 2,814 people who took part in the community class version of Stress Control where a trainer delivers the class to a large number of people. In this study, the average class size was 74.  The class has six sessions and contained the same information as Stress Control at Home.

This research looked at how many people ‘recover’ after attending the Stress Control classes run by the NHS. Stress Control classes are run by many parts of the NHS in the UK. The particular part of the NHS that runs these classes is called NHS Talking Therapies for Anxiety and Depression (previously called IAPT). In order for the NHS to evaluate how well their therapies - individual, group, self-help, etc., are working, they use the idea of ‘Recovery’.  So, a person is said to have ‘recovered’ at the end of the intervention if their scores on both an anxiety questionnaire - GAD7 - and a depression questionnaire - PHQ9 (both of these questionnaires are available in the self-assessment section of the Stress Control at Home website) have returned to the ‘normal’ range at the end of the treatment.

By asking people to complete questionnaires at each of the six sessions, the researchers were able to calculate recovery levels at each session. They found that attending for only three sessions helps only a few people. After four sessions the figure jumps considerably. This improvement continues at 5 sessions, and doing the full course results in the best 'recovery' outcomes.

So, these results led us to use an antibiotic metaphor – to get the best outcome, you should complete every session from start to finish.


*Burns et al. (2016). “Stress Control” as a Large Group Psychoeducational Intervention at Step 2 of IAPT Services. Behavioural and Cognitive Psychotherapy, 2016, 44, 431–443.


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