Editorial Comment from Dr Sato to Relationship between plasma melatonin levels and the efficacy of selective serotonin reuptake inhibitors treatment on premature ejaculation

Abstract

Editorial CommentEditorial Comment from Dr Sato to Relationship between plasma melatonin levels and the efficacy of selective serotonin reuptake inhibitors treatment on premature ejaculationPremature ejaculation (PE) is a common sexual dysfunction. Although recent research has expanded our understanding of the mechanism of ejaculatory function, the entire mechanism of PE is still unclear. 1The present study highlighted the interesting relationship between PE and plasma melatonin level.2 The authors' hypothesis is new and might suggest a novel treatment approach for PE. However, further confirmation of this "melatonin-theory" is required.In the current study, the first interesting finding was a significantly lower serum melatonin level in patients with PE. Actually, I was surprised by the clear difference of serum melatonin level between the PE and control group. Although melatonin might have various physiological actions that include sexual functions, to my knowledge, there is no report that describes such a clear relationship between serum melatonin and ejaculatory function in the human male.1 Putative reasons for lower serum melatonin level in PE patients are unclear. The mechanism of lower melatonin levels inducing PE should be established. As the first step of further investigations, serum melatonin levels in patients with PE would be confirmed with larger cohorts.The second finding of this study was an increased melatonin level after selective serotonin reuptake inhibitor (SSRI) treatment was associated with an improvement in PE. These findings are reasonable. SSRI modulate serotonergic metabolites, and increase the melatonin level and its metabolites, which has been confirmed by previous studies with depressive patients.3,4 Prolongation of intravaginal ejaculation latency time by SSRI has been reported by many previous studies. 2,5 According to results of present study, the authors concluded that an elevated serum melatonin level might be the reason for improvement of PE.However, the present study only showed two expected results induced by SSRI. This study 1 did not show that elevated melatonin improved PE directly. As the next step, to confirm the direct effect of melatonin on PE, melatonin agonist/antagonist should be trialled for patients with PE.We expect to carry out further investigations to prove the "melatonin-theory," and to discover a new etiology and therapeutic approach.