Sleep complaints are common in patients with major depressive disorder (MDD).Venlafaxine is an antidepressant of the serotonin -norepinephrine reuptake inhibitor class. Mirtazapine is a tetracyclic antidepressant (TeCA) used primarily in the treatment of depression. This study compares the effects of venlafaxine and mirtazapine on sleep continuity measures in DSM-IV MDD patients with insomnia.

Patients (N = 37) received initial baseline polysomnography evaluations over 2 consecutive nights.Subjects were randomly assigned to either venlafaxine (75–150 mg/day) or mirtazapine (15–45mg/day)treatment for an 8 week,double -blind,double -dummy treatment trial.Single-night polysomnograms were conducted at weeks 1,2,and 8, with depression ratings assessed at baseline and weeks 1,2, 3,4, 6,and 8.

Patients receiving mirtazapine (N = 20) had significant improvement in objective sleep physiology measures at 8 weeks.Improvement in sleep latency,sleep efficiency,and wake after sleep onset were significant after only 2 weeks of mirtazapine treatment.No significant changes in sleep continuity measures were observed in the venlafaxine group (N = 17).Both groups improved clinicaly in mood and subjective sleep measures from baseline, with no differences between groups.

These date demonstrate the differential effects of mirtazapine and venlafaxine with significant improvement in favor of mirtazapine ,on objective sleep parameters in MDD patients with insomnia.