Premature (Early) Ejaculation 445
having a normal ejaculat ory latency, known as acquired premature (early) ejaculation.  There is
far less known about acquired premature (early) ejaculation than about lifelong premature
(early) ejaculation. The acquired form likely has a later onset, usually appearing during or af-
ter the fourth decade of life. Lifelong is relative ly stable throughout life.  Little is known about
the course of acquired prematur e (early) ejaculation. Reversal of medical conditions such as
hyperthyroidism and prostatitis appears to rest ore ejaculatory latencies to baseline values.
Lifelong premature (early) ejac ulation begins with early sexual experiences and persists
throughout an individual’s life. In approxim ately 20% of men with premature (early) ejacu-
lation, ejaculatory latencies decrease further wi th age. Age and relationship length have been
found to be negatively associated with pr evalence of prematur e (early) ejaculation.
Risk and Prognostic Factors
Temperamental. Premature (early) ejaculation may be more common in men with anx-
iety disorders, especially social  anxiety disorder (social phobia).
Genetic and physiological. There is a moderate genetic contribution to lifelong prema-
ture (early) ejaculation. Premature (early) ejaculation may be associated with dopamine
transporter gene polymorphism or serotonin transporter gene polymorphism. Thyroid
disease, prostatitis, and drug withdrawal are associated with acquired premature (early)
ejaculation. Positron emission tomography measu res of regional cerebral blood flow dur-
ing ejaculation have shown primary activation in the mesocephalic tr ansition zone, includ-
ing the ventral tegmental area.
Culture-Related Diagnostic Issues