Table 1.

Examined studies concerning the multivariate relationship between FM syndrome and alexithymia (TAS-20).

Study	Subjects	Results
Patients with other chronic pain conditions as control group (three studies)
Sayar et al. (2004)	50 FM patients	Significant higher alexithymia scores (total and factor 1 scores) in FM compared to both control groups.
	20 rheumatoid arthritis patients
	42 healthy controls
Steinweg et al. (2011)	48 FM patients	44% of alexithymia in FM group vs. 8% in general medicine group and 21% in rheumatoid arthritis group. Alexithymia was strongly associated with moderate to severe depression.
	36 general medicine patients
	43 rheumatoid arthritis patients
Tuzer et al. (2011)	70 FM patients	Significant higher alexithymia scores in FM sample compared to both CLBP and healthy control groups.
	56 chronic low back pain (CLBP) patients
	72 healthy controls
Healthy controls (one study)
Malt et al. (2002)	42 FM patients	No differences in alexithymia scores between FM group and healthy controls.
	48 healthy controls
No control group (three studies)
Pedrosa-Gil et al. (2008)	40 FM patients	15% of alexithymia in FM group.
Huber et al. (2009)	68 FM patients	Significant differences only on the 1 factor of TAS-20.
Castelli et al. (2012)	55 FM patients	20% of alexithymia in FM group.