The Antidepressant Advisor: A Decision Support System for UK Primary care-a Feasibility Study

To address the urgent need for user-friendly decision support for antidepressant choices in UK primary care, the investigators will probe a specifically tailored innovative tool advising GPs on patients who have not responded to first-line treatments. Despite one promising US study, there is no such tool available in the UK. The US study was based in a private GP setting and employed now outdated treatment algorithms. In contrast, the treatment algorithm implemented in the current decision support tool is based on National Institute for Health and Care Excellence (NICE) guidelines including the latest health technology appraisals. The investigators have further gained the support of the leading UK provider of primary care electronic record systems (EMIS group: >3000 GP practice users) who will develop the software implementation of the algorithm as an add-on tool to their widely employed software.

Considering complex intervention guidance, the study is designed as a feasibility study to provide estimates of the following unknown variables needed to plan a subsequent larger trial: lost to follow-up and recruitment rates, GP satisfaction with the tool, impact on health service use, and standard deviations on our planned primary outcome measure on the self-rated Quick Inventory of Depressive Symptomatology (QIDS-SR16) for a subsequent trial. The investigators will use a single-blinded parallel group cluster-randomised controlled trial design with at least 8 GPs across 8 practices (one per practice) being randomised supported by the Clinical Research Network (CRN) to two arms: 1) Usual care of patients with depression with no computerised decision support, 2) Using the novel computerised decision support tool to assist with antidepressant choices.

The investigators will recruit 8-20 GPs in 8-20 different practices to avoid communication between GPs, each contributing approximately 10 study patients. The EMIS eligibility tool (see below) will identify potential participants by screening for antidepressant and problem history. Blinded practice staff/CRN will ask all eligible patients for consent for contact. Patients will fill in an electronic version of the self-report version of the Primary Care Evaluation of Mental Disorders (PRIME-MD) and provide electronic consent for this. Alternatively, participants will be called to answer the questions over the phone and provide oral consent. Other patients will prefer receiving a mailed printed questionnaire and provide written consent. PRIME-MD has been validated against clinical diagnoses of current major depressive and anxiety disorders, as well as alcohol abuse according to DSM-IV criteria and will be modified to screen for drug abuse and anxiety disorders may be dropped from the screening as they are not exclusion criteria and will be assessed in the in-depth assessment. Patients will further complete self-report versions of the WHO Composite International Diagnostic Interview (CIDI) screening scale for bipolar disorder and 3 screening questions validated in the investigators' group to exclude schizophrenia. Further, the investigators will ask about the inclusion and exclusion criteria for the study, because the information recorded on EMIS is not always complete and does not always include a patient's history with previous GP surgery for example. Eligible patients will be seen for an in-depth assessment by the study research associate (RA) where she will take written informed consent.

2.1.2 Data collection and Assessment for patients meeting the pre-screening criteria

As in the investigators' previous work, the RA will be closely supervised and trained, establishing sufficient inter-rater reliability on semi-structured interviews with the PI before carrying out assessments independently. Apart from the outcome measures, the in-depth assessment will include measuring past subthreshold hypomanic symptoms, and perceived credibility of and expectancy towards treatment using a dedicated questionnaire, and a detailed clinical evaluation whilst accessing patients' EMIS records including: