Refractory period (sex) for treating sexual dysfunction. Sildenafil, used in the treatment of erectile dysfunction, was found in one scientific study to have caused "a decreased postejaculatory erectile refractory time (3.2 ± 0.7 vs. 6.4 ± 0.7 minutes)" in men diagnosed with premature ejaculation. It is additionally proposed that the gonadotropin inhibitory hormone (GnIH), which is considered to inhibit the hypothalamic-pituitary-gonadal axis and sexual functions causes refractoriness of the post-ejaculatory refractory period. This hypothesis also supports the increase of oxytocin and prolactin after orgasm in accordance with the previous studies. One alternative theory explains the male refractory period in terms of a peripheral
Psychological refractory period caffeine intake have also been investigated. PRP is a product of the psychological refractory period paradigm, a paradigm in which two different stimuli are presented in rapid succession, each requiring a fast response. Stimulus onset asynchrony, the time that lapses between the presentations of the two stimuli, acts as the "independent variable" in this paradigm, and the reaction time to the second stimulus acts as the "dependent variable". An example of a PRP paradigm might be that there is a task 1 which requires participants to push the keyboard-letter 'n' with the right index finger when a square frame was