Indeed, IR formulation, even when administered at low doses (30 mg), has been demonstrated to primarily recruit 5-HT1A, 5-HT1D, 5-HT2A, and 5-HT2B serotonergic receptors and α1A, α1B, and α1D adrenergic receptors, thus explaining the clinically observed efficacy of trazodone IR in treating insomnia and anxiety. Here, HTR1A is linked to insomnia measurement.