Katsamanis 2011.

Methods	Study design: randomised controlled trial
Participants	Diagnosis: subthreshold somatisation disorder (abridged somatisation) Method of diagnosis: participants (18‐70 years old) were eligible if no major medical illness explained symptoms after detailed physical and laboratory assessment; individuals must have met criteria for ≥ 4 MUPS out of the 42 somatic symptoms listed in the CIDI rated as currently present if males and at least 6 if female, according to a diagnostic interview Exclusion criteria: history of alcohol/drug abuse (within last 12 months), bipolar or psychotic, unstable medical condition, pregnancy, active suicidal ideation Total number randomised: 48 (10 dropped out, baseline data reported for only 38) Age: intervention group 83% < 40 years (n = 15); control group 40% < 40 years (n = 8) Sex: 79% women; 21% men; for intervention group 83.3% women (n = 15), for control group 75.0% (n = 15) Severity of symptoms at baseline: unclear, participants in both groups met a CGI rating of 4, which equals moderate somatisation Duration of symptoms at baseline: not described Setting: participants were recruited from primary medical clinics and community (advertisements). Treatment: department of psychiatry of a medical school Location: New Jersey, USA Number of treatment centres: 1 Co‐morbidities: 55% met criteria for severe depression (n = 21, HAM‐D 17 criteria), 40% for mild‐to‐moderate depression (n = 15, HAM‐D 17 criteria) and 85% for significant anxiety (n = 23, HAM‐A criteria) Adjunctive therapy: not mentioned Adjunctive medication: psychotropic medication were allowed (Katsamanis 2011, table 3)
Interventions	Participants were randomly assigned to either 1. Psychophysiological treatment + psychiatric consultation intervention (PCI) (n = 24) Duration: 10 weekly sessions during a period of 10 weeks Treatment protocol: psychophysiological treatment: treatment consisted of a manualised intervention, described to participants as an intervention which comprises of a set 'self regulation' techniques that are specifically targeted at particular symptoms of body systems, aiming to assist in coping with physical discomfort and stress (Katsamanis 2011, page 221 for details) PCI: a standard consultation letter was sent to the principal treating physician making recommendations for the ongoing treatment (Katsamanis 2011, Table 1 for details) Therapist: 4 therapists, either master or doctoral level psychologists, 3 of them certified as biofeedback clinicians with at least 3 years of supervised training in psychophysiological treatment 2. PCI alone (n = 24) Duration: NA Treatment protocol: standard consultation letter sent to the treating physician including recommendations for the ongoing treatment (Katsamanis 2011, table 1 for details). Therapist: NA
Outcomes	Time points for assessment: baseline, halfway the intervention (5 weeks) and at the end of treatment (10 weeks) Primary outcome: 1. severity of somatisation (CGI‐SD, clinician rated) Secondary outcome: 1. level of depression and anxiety (HAM‐D and HAM‐A) 2. participants' rating of physical functioning (MOS, SF‐36) 3. participants' rating of mental functioning (MOS, SF‐36)
Notes	Date of study: the study took place between June 2006 and August 2008 Funding source: National Institue of Mental Health Declarations of interest among the primary researchers: design based on Allen. Cross‐over group (receiving treatment after wait condition) not used
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated random number sequence
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding of participants and personnel (performance bias) All outcomes	High risk	Personnel and participants not blinded
Blinding of outcome assessment (detection bias) All outcomes	High risk	Outcome assessors were masked but almost all outcomes were participant reported
Incomplete outcome data (attrition bias) All outcomes	High risk	10/48 dropped out and for several outcomes even more (> 20%)
Selective reporting (reporting bias)	Low risk	All intended outcomes reported
Treatment fidelity	Low risk	Treatment was based on a manual, containing guidelines, developed before the study (available from the authors)
Researcher allegiance	Low risk	No indication that researchers had a preference for 1 of the treatment modalities
Other bias	Unclear risk	Large difference in age between groups suggests randomisation failed