Box 1.

The PROSPECTS study

The PROSPECTS study is a Dutch longitudinal cohort study following patients (n = 325) with persistent somatic symptoms (PSS). Patients with PSS aged between 18 and 70 years were recruited from general practices (n = 218) and specialised PSS programmes in secondary and tertiary care organisations (n = 107) across the Netherlands in 2013–2015. Initially patients were followed over a period of 3 years with five measurements in time (baseline, 6-, 12-, 24- and 36-months’ follow-up). In 2017, the follow-up period was extended and the study is still ongoing. Baseline characteristics and information on the recruitment process and first 2 years of follow-up have been published elsewhere.30,31 Definition of PSS: PSS was defined as the presence of physical symptoms that had lasted at least several weeks and for which no sufficient explanation was found after proper medical examination by a physician. This is in line with the current Dutch multidisciplinary and general practice guidelines for medically unexplained physical symptoms.23,25