Effects of Approved Pharmacological Interventions for Insomnia on Mood Disorders: A Systematic Review.

Objective: Insomnia can be a contributing factor, a comorbid disorder, or a transdiagnostic element to several mental disorders, including mood disorders (MDs). A recent meta-analysis has already shown the effectiveness of cognitive behavioral treatment (CBT) for insomnia that is comorbid with MDs. This work aimed to systematically review data on pharmacological insomnia treatment in the context of MDS. In agreement with the current guidelines, pharmacological interventions for insomnia include gamma-aminobutyric acid (GABA)A receptor agonists such as short-medium acting benzodiazepines and benzodiazepine receptor agonists - Z-drugs, melatonergic receptors agonists, specifically melatonin 2 mg Prolonged Release (PR) and ramelteon, and dual orexin receptors antagonists (DORA) such as daridorexant, lemborexant, and suvorexant. Method: A systematic search was carried out on PUBMED database, according to the PRISMA Guidelines. Results: Thirty-three papers, 15 on gabaergic receptor agonists, 14 on melatonergic receptor agonists and 4 on DORA, were selected. Conclusions: Available data suggests that the treatment of insomnia symptoms with specific pharmacological options can improve both insomnia and comorbid conditions. Specifically, eszopiclone and melatonin 2 mg PR have demonstrated promising outcomes. Moreover, daridorexant and suvorexant, both belonging to the DORA class, have demonstrated efficacy in treating insomnia and mood symptoms. To summarize, current literature would suggest that targeting insomnia could potentially regulate the sleep system and, as such, improve mood symptoms.