The definition of premature ejaculation has changed over time and while there has been an attempt to create a single definition for clinicians and researchers, much of the research on premature ejaculation does not use the same definition.
The DSM defines premature ejaculation as
…the persistent or recurrent onset of orgasm and ejaculation with minimal sexual stimulation before, on, or shortly after penetration and before the person wishes it… The disturbance must cause marked distress or interpersonal difficulty [and]…The premature ejaculation is not due exclusively to the direct effects of a substance (e.g., withdrawal from opioids).
In 2008 the International Society for Sexual Medicine released a new definition of premature ejaculation, in consultation with “21 internationally recognized experts” who defined it as follows:
Premature ejaculation is a male sexual dysfunction characterized by ejaculation which always or nearly always occurs prior to or within about one minute of vaginal penetration; and inability to delay ejaculation on all or nearly all vaginal penetrations; and negative personal consequences, such as distress, bother, frustration and/or the avoidance of sexual intimacy.
Premature ejaculation may be lifelong (sometimes called “primary premature ejaculation”), meaning that a man has experienced it since he first started engaging in sexual behaviors with others, or acquired (also called “secondary premature ejaculation”), meaning that he previously did not experience premature ejaculation but it has developed at a later point.
American Psychiatric Association. Diagnostic and Statistical Manual - Text Revision (DSM-IV-TR™, 2000). Washington, DC: American Psychiatric Association.
International Society for Sexual Medicine. “ISSM Definition of Premature Ejaculation.”