Major depression is characterised by a persistent low mood and loss of interest and pleasure. These symptoms are often accompanied by loss of appetite, insomnia, fatigue, poor concentration, inappropriate guilty feelings and even suicide. Depression was the third leading cause of disease burden among all diseases experienced by humankind in 2002. Antidepressants are used in treatment for major depression. They are the mainstay of treatment. Among them, mirtazapine is known to have a unique pharmacological profile and thus is supposed to differ in its efficacy and adverse effects profile in comparison with other antidepressants.
The evidence from this review, which included findings from 29 randomised controlled trials (4974 participants in total), suggests that mirtazapine is likely to have a faster onset of action than the most frequently used type of antidepressants, which are the selective serotonin reuptake inhibitors (SSRIs). It would appear that mirtazapine is superior to SSRIs at the end of treatment over 6 to 12 weeks. Mirtazapine causes adverse events that lead to a similar frequency of dropouts as SSRIs and tricyclic antidepressants, although adverse event profile of mirtazapine is unique. Mirtazapine is likely to cause weight gain or increased appetite and somnolence but is less likely to cause nausea or vomiting and sexual dysfunction than SSRIs.