Scientists have long suspected a genetic link to certain forms of premature ejaculation. However, studies have been inconclusive in isolating the gene responsible for lifelong PE. The nucleus paragigantocellularis of the brain has been identified as having involvement in ejaculatory control. Other researchers have noted that men who have premature ejaculation have a faster neurological response in the pelvic muscles.PE may be caused by prostatitis or as a medication side effect. PE has been classified into four subtypes - lifelong, acquired, variable and subjective PE. The pathophysiology of lifelong PE is mediated by a complex interplay of central and peripheral serotonergic, dopaminergic, oxytocinergic, endocrinological, genetic and epigenetic factors. Acquired PE may occur due to psychological problems - such as sexual performance anxiety, and psychological or relationship problems - and/or co-morbidity, including Erectile dysfunction, prostatitis and hyperthyroidism. Mechanism
The physical process of ejaculation requires two actions: emission and expulsion. The emission is the first phase. It involves deposition of fluid from the ampullary vas deferens, seminal vesicles and prostate gland into the posterior urethra. The second phase is the expulsion phase. It involves closure of bladder neck, followed by the rhythmic contractions of the urethra by pelvic-perineal and bulbospongiosus muscle and intermittent relaxation of external urethral sphincters.Sympathetic motor neurons control the emission phase of ejaculation reflex, and expulsion phase is executed by somatic and autonomic motor neurons.
These motor neurons are located in the thoracolumbar and lumbosacral spinal cord and are activated in a coordinated manner when sufficient sensory input to reach the ejaculatory threshold has entered the central nervous system. Intromission time
The 1948 Kinsey Report suggested that three-quarters of men ejaculate within two minutes of penetration in over half of their sexual encounters.Current evidence supports an average intravaginal ejaculation latency time (IELT) of six and a half minutes in 18- to 30-year-olds. If the disorder is defined as an IELT percentile below 2.5, then premature ejaculation could be suggested by an IELT of less than about two minutes. Nevertheless, it is possible that men with abnormally low IELTs could be satisfied with their performance and do not report a lack of control. Likewise, those with higher IELTs may consider themselves premature ejaculators, have detrimental side effects normally associated with premature ejaculation, and even benefit from treatment. Diagnosis
The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) defines premature ejaculation as "A persistent or recurrent pattern of ejaculation occurring during partnered sexual activity within approximately 1 minute following vaginal penetration and before the person wishes it," with the additional requirements that the condition occurs for a duration longer than 6 months, causes clinically significant distress, and cannot be better explained by relationship distress, another mental disorder, or the use of medications. These factors are identified by talking with the person, not through any diagnostic test.