Nocturnal emissions or wet dreams: modern evidence from a systematic scoping review

Nocturnal emissions (NEs), or "wet dreams," are involuntary ejaculations occurring during sleep. Although NEs are a normal component of male puberty, uncertainties have persisted regarding their physiology, epidemiology, and clinical significance.

To systematically review the literature on NEs, summarizing epidemiological data, physiological mechanisms, cultural perspectives, and clinical relevance.

A systematic search of PubMed and EMBASE (from inception to April 2025) was performed. Grey literature was included to minimize publication bias, and non-English studies were translated. The FAERS and EudraVigilance databases were queried for drug-related NEs. No exclusions were made based on study design. The risk of bias was assessed with the Newcastle-Ottawa Scale, and qualitative works were appraised narratively.

A total of 157 sources were included. The first NE typically occurs between 12.6 and 15.6 years, most often at 13-14, with modest cross-cultural variation. Prevalence resulted high (70%-90%), especially among adolescents, though lower in some Asian cohorts and rare in individuals with neurological impairment. Data on frequency were scarce and inconsistent. Educational gaps were evident and misconceptions remain widespread, particularly in South Asia, where NEs are central to Dhat syndrome. Evidence did not support the historical view of NEs as a compensatory release under conditions of low sexual outlet. NEs occurred with or without erotic dreams. Findings from studies on spinal cord injury and psychogenic anejaculation confirm that they can arise independently of supraspinal control. Their association with sleep orgasms and sleep-related erections remained uncertain. Hormonal, parental, and prenatal influences appeared modest. NEs may help in differentiating psychogenic anejaculation and occasionally serve as a sperm source for assisted reproduction.

NEs are a nearly universal, physiological phenomenon with cultural, educational, and clinical dimensions and they remain relevant to sexual development, adolescent health, and certain diagnostic contexts. High-quality prospective research is needed to clarify mechanisms and implications.