Studies of any design that compared paroxetine with mirtazapine, in patients of any age, who had major depressive disorder, were included in the review. It appears that any trials had to include patients who met Diagnostic and Statistical Manual of Mental Disorders IV Text Revision (DSM-IV-TR) criteria for a single or recurrent major depressive episode, and have a score of at least 18 on the Hamilton Rating Scale for Depression (HRSD). The outcomes of interest were response (50% reduction in HRSD score, from baseline), remission (score of 7 or less on the HRSD), symptom reduction, mean time to response, adverse events, and drop-outs due to adverse events.
In the included studies, the mean age of the patients ranged from 40 to 72 years, and the percentage of women ranged from 50 to 76. All studies were conducted in out-patient settings. The paroxetine dose ranged from 10mg to 40mg, and the mirtazapine dose ranged from 15mg to 45mg. The treatments lasted from to six weeks to 24 weeks.
The authors did not state how many reviewers selected studies for inclusion.