The data from previous studies suggested that folate serum level predicts outcome of treatment in patients who failed to respond to SSRI.

We examined the relationship of serum folate level and response to treatment with various antidepressant interventions (antidepressants, combinations of antidepressants and augmentations) in patients who had failed to respond to at least one previous antidepressant treatment.

Eighty-four inpatients (mean age=46.2±11.3 years, 69% woman) with major depression according to DSM IV and without gastrointestinal or other comorbidities that might influenced folate level were enrolled to the study. Clinical status was assessed using MADRS, CGI and BDI-SF at baseline and at the end of study (mean length of treatment- 5.2±0.9 weeks) and response was defined as reduction of MADRS score≥50%. Folate serum levels were determined before start of treatment (normal level>2.5ng/ml).

Low folate level was detected only in 3 patients (2 responders) in our sample. Responders (54%) and non-responders were not different in baseline folate level as well as in clinical a demographic parameters with exception of number of previous unsuccessful treatments of index episode. Furthermore we did not find any correlations between folate level and baseline or final MADRS score as well as reduction of MADRS respectively.

Despite encouraging data from previous studies, based on our data we did not suppose association of baseline serum folate level and outcome of treatment in resistant patients.

This study was supported by grants of Ministry of Health of Czech Republic NS 10368-3 and MZ0PCP2005.