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Case study: CASPER trial - impact case study

The CASPER trial was funded by the NIHR Health Technology Assessment (HTA) programme and supported by the NIHR Clinical Research Network (CRN). Find out about NIHR support for mental health research here.

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CASPER trial: Research into depression amongst the over 65s

CASPER trial: CollAborative care and active surveillance for Screen-Positive EldeRs with subthreshold depression (CASPER)

Study aim:

Depression is common in the over 65 age group, with around 22% of men and 28% of women affected. Yet it often goes unrecognised and untreated in primary care - with an estimated 85% of older people with depression receiving no help at all.

Despite the prevalence of depression in older people, prior to CASPER there was little evidence to guide the primary care management of depressive symptoms and the prevention of more severe disorders in the over 65s age group.

The CASPER trial, which forms part of a wider programme of research, specifically set out to evaluate whether the addition of a collaborative care intervention can prevent more severe depression in older people and help to reduce depressive symptoms in those with lower severity disorders (subthreshold depression).

To test the hypothesis, the team developed a collaborative care approach including behavioural activation, specifically aimed at older people with depressive symptoms - which could be delivered in conjunction with usual care provided by a GP.

Study summary:

Between June 2011 and July 2013, 705 participants aged 65 and over with subthreshold depression were recruited to the study.

Participants were eligible to take part if they reported depressive symptoms in response to depression screening questions (Whooley), and found to have subthreshold depression according to standardised diagnostic criteria.

Participants were randomly allocated to receive either usual care from their GP (361), or usual GP care with the addition of collaborative care (344). Treatment allocation was concealed from the researchers at the point of recruitment.

The intervention group received a programme of collaborative care delivered by a case manager, for an average of six sessions over eight weeks. This included telephone support, symptom monitoring and active surveillance. At the centre of collaborative care was a brief but practical form of psychological therapy known as ‘behavioural activation’. The first session was delivered face to face, and subsequent sessions by telephone.

All participants were followed up for 12 months. To assess their general and mental wellbeing - both cohorts completed questionnaires at the start of the study, then again at 4 and 12 months. The primary outcome was self-reported symptoms of depression, assessed with the Patient Health Questionnaire-9 items (PHQ-9).

NIHR Clinical Research Network support

Dr Dean McMillan, co-investigator and lead Clinical Psychologist for the CASPER programme, said:  “To meet the very ambitious recruitment targets required for this study, the support provided by the NIHR CRN was invaluable. This included identifying suitable, research-ready GP practices across the north of England and help in sending out over 32,000 letters to potential participants.”

“With CRN support - not only were we able to achieve our recruitment target early - we even exceeded our target. This goes to show that when the CRN gets behind studies, the UK is the envy of the world in terms of how well we can recruit to clinical research studies.”

“This is the largest trial of its kind ever undertaken in the UK, and we have produced evidence that can now inform the provision of primary care for older people with depression.   This research was commissioned by NIHR to meet the needs of NHS patients, and we know that we would not have been able to deliver this programme without the support of CRN.  When I speak about the results of this trial, I am proud to be able to highlight the integral role of the CRN in producing world-leading research.”

Professor Simon Gilbody, Chief Investigator for the CASPER programme

Key features

•    Chief investigator: Professor Simon Gilbody, University of York
•    Participants: 705 older people, aged 65 and over (mean age 77)
•    Number of sites: 32 primary care centres across four centres in the north of England: York, Leeds, Durham and Newcastle upon Tyne.
•    Funding: NIHR Health Technology Assessment (HTA) programme funds


Study outcome:

Clinical effectiveness

The study showed that those in the treatment group were less likely to be severely depressed after a year.

After 4 months, there was evidence of a statistically significant benefit for collaborative care in terms of the primary outcome of depression severity. The benefit was sustained at 12 months alongside an observed preventative effect in developing case-level depression.

Approximately half the number of patients in the collaborative care group went on to develop clinical levels of depression after 12 months than those in the control group - halving the rate of clinical depression onset.

Cost effective analysis

Not only was the collaborative care with behavioural activation shown to be clinically effective - it also provided to be very good value for money. The health economic analysis indicated that the intervention was below the National Institute for Health and Care Excellence (NICE) cost-effectiveness threshold.


The CASPER trial has shown that collaborative care for sub-threshold depression has the potential to be rolled out by the NHS, improving outcomes and achieving cost savings.

Following the positive results in terms of demonstrating preventative effect, the trial’s findings are helping to inform national guidance on the management of depression.

The trial also has generated significant interest and investment from a number of charities and research organisations - leading to further research into the intervention and commissioning of training around the treatment approach.

Researchers in Australia have replicated the CASPER trial’s methodology in a separate study, currently ongoing, which will add further evidence around the efficacy of this treatment approach.

Funding has also been provided by the University of York to roll out training and learning from CASPER to Improving Access to Psychological Therapies (IAPT) practitioners. The CASPER team has delivered a number of one day workshops to healthcare professionals working in IAPT across England to help improve treatment of subclinical depression.

A grant has also been awarded by NIHR Public Health Research (PHR) to train healthy living practitioners in pharmacies to deliver the intervention in community settings.  

The Thalidomide Trust has commissioned a programme of training for people with thalidomide to use collaborative care through a peer support approach. While Age UK have also approached the research team to deliver further training to their staff.

“As one of the first trials to demonstrate the efficacy of an intervention with a substantial preventative effect against developing clinical depression in older adults - the collaborative care approach holds significant potential for roll out on the NHS."

Professor Simon Gilbody, CASPER Chief Investigator and Professor of Psychological Medicine and Health Services Research 

Further reading: