Objectives:
Selective serotonin reuptake inhibitors (SSRIs) are the most commonly used drugs to treat major depressive disorder (MDD). However, about 50% of MDD patients do not achieve treatment response to SSRIs and there is little evidence on which drugs are effective as second-line treatment in those who do not respond to SSRIs.

Methods:
In this work, the data of 79 patients with MDD were analyzed to evaluate the effectiveness of trazodone XR in the group of individuals treated de novo and those switched to trazodone XR after failed treatment attempt with SSRIs. The assessments were performed at baseline and weeks 2, 4, 8 and 12 using tools to evaluate the degree of: depression (Montgomery-Åsberg Depression Rating Scale, clinician and patient-rated Quick Inventory of Depressive Symptomatology – the primary endpoints of the study), therapeutic effectiveness (Clinical Global Impression Scale), anhedonia (Snaith-Hamilton Pleasure Scale), anxiety (Hamilton Anxiety Rating Scale), insomnia (Athens Insomnia Scale), psychosocial functioning (Sheehan Disability Scale) and sexual functioning (Female Sexual Function Inventory in women/International Index of Erectile Function in men).

Results:
The rates of treatment response and remission were largely similar in both studied groups.

Conclusions:
The results showed that effectiveness of trazodone XR in the treatment of patients with MDD who did not respond to SSRIs administered as first-line treatment of a particular depressive episode was comparable to that noted in patients treated de novo. Furthermore, trazodone XR effectively improved depression, anxiety, insomnia, anhedonia and psychosocial functioning in both studied groups. Additionally, trazodone XR as secondline treatment improved sexual functions in male subjects previously treated with SSRIs.