Somatoform disorders are characterised by persistent physical symptoms that suggest the presence of a medical condition, but are not explained fully by that condition or by the direct effects of substance misuse or mental disorder (DSM-IV).1 The prevalence of somatoform disorders is estimated at 6% in the general population.2 Patients with such disorders usually have high functional impairment, 3,4 are difficult to treat, 5,6 and show high utilisation of medical care. 7 Moreover, it typically takes years before they are referred to mental healthcare. 6,8,9 A strictly somatic approach and unnecessary diagnostic examinations may increase somatising behaviours, 10 and lead to chronic symptoms and high medical costs: 7,11,12 these findings emphasise the need for early intervention.13 Psychotherapy may be a viable treatment option given the role of behavioural, cognitive and emotional processes in these disorders and their high degree of comorbidity with mental disorders.14-16 Some reviews and meta-analyses suggest that psychotherapy may be effective in patients with somatoform disorder. [17][18][19] However, these reviews were restricted to psychodynamic psychotherapy only, 17 or predominantly involved groups with less severe disorder, with functional neurological or conversion disorder generally being excluded. 18 Hypochondriasis and body dysmorphic disorder were typically included in these reviews, 19 although it is still a matter of debate whether these conditions should be classified as somatoform disorder.14, 20 The results of previous reviews cannot always be generalised to patients with strictly defined somatoform disorder in secondary and tertiary care, as these patients are generally more impaired than those seen in primary care. 21 Finally, previous meta-analyses typically included only randomised trials, often excluding effectiveness studies, [22][23][24] whereas the inclusion of both randomised and non-randomised studies allows the meta-analytic comparison of effect sizes between these designs.The aim of our meta-analysis therefore was to examine the effectiveness of psychotherapy for patients with strictly defined, severe somatoform disorder treated in secondary and tertiary care. To that aim, we compared effect sizes from pre-to post-treatment and from post-treatment to follow-up of psychotherapy and treatment as usual, excluding waiting-list control groups. This study focused on pre-to post-treatment contrasts, and not on between-group contrasts, given the limited number of controlled treatment studies in this context. Given the small number of studies included, moderators of treatment effect were examined only exploratively. We examined methodological quality of the studies, 25 intervention characteristics (type, modality, frequency and length), 26 and whether treatment was offered in tertiary (multimodal and integrative) or secondary care settings, 18 as potential factors influencing treatment effectiveness.
MethodA multiple-phase search was conducted in March 2010 to retrieve as many studies as pos...