Introduction

In men, sexual dysfunction refers to difficulties engaging in sexual intercourse. Sexual dysfunction encompasses a variety of disorders that affect sex drive (libido), the ability to achieve or maintain an erection (erectile dysfunction, or impotence), ejaculation, and the ability to achieve orgasm.

Sexual dysfunction may result from either physical or psychologic factors; many sexual problems result from a combination of both. A physical problem may lead to psychologic problems (such as anxiety, fear, or stress), which can in turn aggravate the physical problem. Men sometimes pressure themselves or feel pressured by a partner to perform well sexually and become distressed when they cannot (performance anxiety). Performance anxiety can be troublesome and further worsen a man's ability to enjoy sexual relations.

Erectile dysfunction is the most common sexual dysfunction in men. Decreased libido also affects some men. Problems with ejaculation include uncontrolled ejaculation before or shortly after penetrating the vagina (premature ejaculation), ejaculation into the bladder (retrograde ejaculation), and blockage (obstruction) of the ejaculatory ducts.

See the sidebar Psychologic Causes of Sexual Dysfunction.

Normal Sexual Function

Normal sexual function is a complex interaction involving both the mind (thoughts, memories, and emotions) and the body. The nervous, circulatory, and endocrine (hormonal) systems all interact with the mind to produce a sexual response. A delicate and balanced interplay among all parts of the nervous system controls the sexual response in men.

Desire (also called sex drive or libido) is the wish to engage in sexual activity. It may be triggered by thoughts, words, sights, smell, or touch. Desire leads to the first stage of the sexual response cycle, excitement. Excitement is sexual arousal. During excitement, blood flow to the penis increases, leading to an erection. Also, muscle tension increases throughout the body. In the plateau stage, excitement and muscle tension are maintained or intensified. Orgasm is the peak or climax of sexual excitement. At orgasm, muscle tension throughout the body further increases. The man experiences contractions of the pelvic muscles followed by a release of muscle tension. Semen is usually, but not always, ejaculated from the penis. Although ejaculation and orgasm often occur nearly simultaneously, they are separate events. Ejaculation can occur without orgasm. Also, orgasm can occur in the absence of ejaculation, especially before puberty, or with the use of certain drugs (such as some antidepressants). Most men find orgasm highly pleasurable. In resolution, a man returns to an unaroused state. After orgasm, men cannot have another erection for some time (refractory period), often as short as 20 minutes or less in young men but much longer in older men. The time between erections generally increases as men age.

See the sidebar Sexual Activity and Heart Disease.