A recent study examined the effectiveness of ultra-low-dose mirtazapine (3.75 mg) in improving insomnia symptoms among veterans, with findings suggesting positive outcomes without significant next-day effects. The research, conducted by a team including Rony Berbara, MD, and others, involved a retrospective chart review from September 5, 2024, to March 7, 2025.
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The study included 53 veterans aged 31-81 who experienced insomnia and were treated with the low-dose mirtazapine after traditional sleep aids proved ineffective. Insomnia severity was measured using the Insomnia Severity Index (ISI) at baseline and follow-up visits. Results showed that 47% of participants achieved a clinically significant decrease in ISI scores (by more than 7 points), and 32% reported recovery, defined as an ISI score of 7 or lower.
The mean ISI score also decreased from 20.4 (baseline) to 8.9 (1-3 months post-treatment), indicating improvement in insomnia severity. Among those who completed the treatment, all patients reported stable or reduced ISI scores over the treatment period (mean [SD] change: 11.3 [6.46]). However, 17 out of 53 participants did not complete their treatment, highlighting an aspect of treatment adherence.
The report pointed out that low doses of mirtazapine may be more appropriate for patients with chronic insomnia, particularly when cognitive-behavioral therapy is not suitable. While mirtazapine is often used in higher doses for depression (15-45 mg), the benefits of lower doses include improved sleep duration and architecture without residual sedation.
Despite these findings, the study acknowledges limitations due to its small, retrospective design. It lacked a control group, which might affect the generalizability of the results. Nonetheless, the evidence suggests that ultra-low-dose mirtazapine may serve as a viable option for those struggling with chronic insomnia, warranting further investigation in randomized controlled trials.