Amitriptyline (tricyclic antidepressant with H1, 5HT2, and cholinergic muscarinic antagonism) and trazodone (serotonin antagonist and reuptake inhibitor (SARI) with 5HT1a, 5HT2, and alpha1 antagonist actions) are frequently used for the treatment of insomnia in Italy despite the scarce evidence of their efficacy [43,80] both in the general population and in cancer patients [15,32,51,56,59]. This evidence concerns the gene HTR2A and insomnia measurement.