RESULTS
Somatoform Disorders Studied in the Randomized
Clinical Trials
A total of 34 randomized clinical trials (RCTs) involving
3922 patients were included (Table 1). Two thirds of the
studies involved somatization disorder (SD) (n 4 studies)
(20 –23) and lower threshold variants, such as abridged versions
of SD (n 9) (24 –32) and medically unexplained
symptoms (n 10) (33– 42). There were five studies of
hypochondriasis (43– 47), three of conversion disorder (48 –
50), and three of body dysmorphic disorder (BDD) (51–53).
Three of the trials included patients with undifferentiated
somatoform disorder (USD) but did not report the results
separately for USD (30 –32). Also, most or all of the patients
in the nine studies of abridged versions of SD and the ten
studies of medically unexplained symptoms would likely meet
the criteria for USD. Finally, although there are a large number
of RCTs in the literature focused on patients with specific
pain conditions or chronic pain in general, there were no
studies of Diagnostic and Statistical Manual of Mental Disorders,
4th Edition (DSM-IV) pain disorder per se.