Sexual desire disorders or decreased libido can be caused by a decrease in normal estrogen (in women) or testosterone (in both men and women) production. Other causes may be aging, fatigue, pregnancy, medications (such as the SSRIs) or psychiatric conditions, such as depression and anxiety.

For both men and women, these conditions can manifest as an aversion to, and avoidance of, sexual contact with a partner. In men, there may be partial or complete failure to attain or maintain an erection, or a lack of sexual excitement and pleasure in sexual activity.

Orgasm disorders are a persistent delay or absence of orgasm following a normal sexual excitement phase. The disorder can occur in both women and men. Again, the SSRI antidepressants are frequent culprits -- these can delay the achievement of orgasm or eliminate it entirely.

Sexual pain disorders affect women almost exclusively and are known as dyspareunia (painful intercourse) and vaginismus (an involuntary spasm of the muscles of the vaginal wall that interferes with intercourse). Dyspareunia may be caused by insufficient lubrication (vaginal dryness) in women.

Poor lubrication may result from insufficient excitement and stimulation, or from hormonal changes caused by menopause, pregnancy, or breast-feeding. Irritation from contraceptive creams and foams can also cause dryness, as can fear and anxiety about sex.

It is unclear exactly what causes vaginismus, but it is thought that past sexual trauma (such as rape or abuse) may play a role. Another female sexual pain disorder is called vulvodynia or vulvar vestibulitis. In this condition, women experience burning pain during sex which seems to be related to problems with the skin in the vulvar and vaginal areas. The cause is unknown.

The problem of an inadequate erection is probably one of the biggest issues a man confronts. Most men experience erectile problems on occasion, but impotence, also called erectile dysfunction, is defined as "the persistent failure to develop and maintain erections of sufficient rigidity for penetrative sexual intercourse." Of course, men have other kinds of sexual problems including lack of desire and problems with ejaculation, yet impotence is the most common and troubling.

A recent study estimates that 30 million men suffer from various degrees of erectile dysfunction. This can range from mild to severe. It is clearly an age-related phenomenon with the prevalence of erectile dysfunction increasing significantly with age. Surprisingly, by the time men reach 40, 5% of them are completely impotent never achieving an erection rigid enough for penetration. Approximately 15% have significant problems achieving or maintaining an erection.

The creation of an erection is an extremely complicated cascade of events that requires many different things to happen. There are numerous chemical transmitters involved in this including epinephrine, norepinephrine, acetylcholine, prostaglandins and nitric oxide. The exact mechanism by which erection occurs is still unclear but we do know that the neural input from the brain is extremely important. Reflex erections, as seen in people with cord damage such as paraplegics, are often poor erections and not sustainable for prolonged periods of intercourse.

Erections can change over time, sometimes stronger or weaker than other times. When men are in their teens they often have little control over their erections and obtain erections when not in a sexual situation. For most men this stops in their late teens to early twenties. As men get older, erections may not always be obtained when they want one. Almost every man has the occasional time when their erection is less strong than they would like but sometimes it becomes a problem.

In order to increase the size of an erection, there must be an increase in blood flow and, at the same time, the blood has to be prevented from leaving the penis.

Nerves must be working normally for a man to get and keep an erection. Nerve damage can result from diabetes, multiple sclerosis, prostate surgery or damage to the spinal cord.

Abnormal levels of certain hormones, such as testosterone, thyroid hormone and a pituitary hormone known as prolactin, can interfere with erections and sex drive (libido). This is an uncommon cause of erectile dysfunction.

A man with erectile dysfunction has either a problem getting an erection or difficulty maintaining one. This usually interferes with sexual activity by preventing penetration during intercourse.

Little is known about how to prevent erectile dysfunction. However, avoiding cigarette smoking and maintaining normal blood pressure and cholesterol levels can help because smoking and high cholesterol can affect blood vessels. Men with diabetes should strive to keep blood sugar levels under control. Because certain medications have been associated with erectile dysfunction, ask your doctor about possible side effects before you start using any new prescription.

If Sildenafil (Viagra), vardenafil (Levitra) and tadalafil (Cialis) drugs don't work or cannot be used because of potential side effects, your doctor can recommend other therapies. The drug alprostadil (Caverject, Edex, Muse) causes blood vessels to widen. This can allow blood to flow more freely in the penis, leading to an erection. The drug can be injected with a tiny needle, or a small pellet (suppository) can be inserted into the opening of the penis. Suppositories like this are effective in approximately two-thirds of men. Injections are effective about 80 percent of the time.

Terms and definitions

Anxiety

• A state of uneasiness and apprehension, as about future uncertainties.


• Worry or tension in response to real or imagined stress, danger, or dreaded situations. Physical reactions such as fast pulse, sweating, trembling, fatigue, and weakness may accompany anxiety.

Impotence

• The inability to achieve and sustain penile erections.

Thyroid

• A gland in the throat that produces hormones that regulate growth and metabolism.


• A large gland in the neck that functions in the endocrine system. The thyroid secretes hormones that regulate growth and metabolism.

Antihistamines

• A drug used to counteract the physiological effects of histamine production in allergic reactions and colds.

Antihypertensives

• Reducing or controlling high blood pressure.

Depression

• In psychiatry, a symptom of mood disorder characterized by intense feelings of loss, sadness, hopelessness, failure, and rejection.

Ejaculation

• The expulsion of seminal fluid from the urethra of the penis during orgasm.


• The process of ejecting semen from the penis, and is usually accompanied by orgasm as a result of sexual stimulation.

Erection

• The firm and enlarged condition of a body organ or part when the erectile tissue surrounding it becomes filled with blood, especially such a condition of the penis or clitoris.

Estrogen

• Any of several steroid hormones produced chiefly by the ovaries and responsible for promoting estrus and the development and maintenance of female secondary sex characteristics.


• Any one of a group of hormones synthesized by the reproductive organs and adrenal glands in females and, in lesser quantities, in males.

Frigidity

• The state of marked or abnormal sexual indifference.


• Sexual unresponsiveness (especially of women) and inability to achieve orgasm during intercourse.

Hormone

• A substance, usually a peptide or steroid, produced by one tissue and conveyed by the bloodstream to another to effect physiological activity, such as growth or metabolism.

Orgasm

• The peak of sexual excitement, characterized by strong feelings of pleasure and by a series of involuntary contractions of the muscles of the genitals, usually accompanied by the ejaculation of semen by the male.


• The highest point of sexual excitement, marked by strong feelings of pleasure and marked normally by ejaculation of semen by the male and by vaginal contractions within the female.

Paraplegics

• Complete paralysis of the lower half of the body including both legs, usually caused by damage to the spinal cord.

Penis

• The male organ of copulation in higher vertebrates, homologous with the clitoris. In mammals, it also serves as the male organ of urinary excretion.


• The organ of the male reproductive system through which semen passes out of the body during sexual intercourse. The penis is also an organ of urination.

Prostate

• Gland in males that surrounds the urine tube (urethra) at the base of the bladder.


• A firm partly muscular chestnut sized gland in males at the neck of the urethra; produces a viscid secretion that is the fluid part of semen.

Stress

• A state of extreme difficulty, pressure, or strain.


• A physical and psychological response that results from being exposed to a demand or pressure.

Testosterone

• A white crystalline steroid hormone, C19H28O2, produced primarily in the testes and responsible for the development and maintenance of male secondary sex characteristics. It is also produced synthetically for use in medical treatment.

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