Normal sexual function is the result of a complex interaction between psychological, physiological and socio-cultural factors. Stress, difficulties in a relationship or marriage, age, menopause or andropause, medical comorbidities and various drug treatments are just some of the many underlying causes of low sexual desire or low libido in men and women.

If low libido also incorporates an element of distress, it can be classified as a hypoactive sexual desire disorder. This diagnosis is currently defined by The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders 4 (DSM-IV) as a recurrent or persistent deficiency or absence of sexual desire for sexual activity that, in turn, causes marked distress or interpersonal difficulties.

Causes of low libido

The prevalence of low sexual desire shows an increase with age, partly reflecting the normal aging process. As circulating levels of testosterone gradually decrease in aging men and women alike, it can lead to impairment in sexual drive, reduced libido and all the accompanying symptoms of limited androgen exposure (i.e. decreased muscle mass and bone density).

Potential psychological and sociological predisposing or prolonging factors should be sought. Challenging living conditions, anxiety, depression, substance abuse and a history of sexual abuse represent common causes of a diminished sex drive. Even environmental factors such as prolonged exposure to bright light or noise can result in low libido.

Medical comorbidities associated with low sexual desire include underactive thyroid gland, diabetes, obesity, pituitary disorders (namely hyperprolactinemia), malignancies, neurological conditions and cardiovascular disease. In women, premature or surgical menopause and other chronic gynecological conditions such as pelvic inflammatory disease, endometriosis or vaginal atrophy may cause dyspareunia (painful sexual intercourse), and subsequently low sex drive.

Certain medications can also reduce libido – primarily antihypertensives (beta-blockers), antidepressants, antiepileptics, antipsychotics, hormonal contraception, as well as the specific drugs that block the effects or reduce the production of testosterone. Decreased libido is also a side-effect of statins, which are often used for the treatment of hypercholesterolemia.

Questionnaire-based tools have been developed for diagnosing low sexual desire, which often include an assessment of distress to diagnose hypoactive sexual desire disorder. The most commonly used test in women is a brief diagnostic instrument named the decreased sexual desire screener (DSDS).

Treatment modalities

The intrinsically complex nature of sexual drive and function requires a holistic approach to this problem, as there can be many underlying causes. The history should unveil any medical causes of low libido or other sexual disorders that need to be addressed, and also highlight any psychological factors.

Psychological interventions are often sufficient in tackling the problem, considering there are no physical factors that can affect libido. A wide range of therapy modalities could be helpful, including basic psychosexual counseling, relationship counseling and cognitive-behavioral psychotherapy. Basic sexual counseling often includes education on basic anatomy and physiology, insight into the normal sexual response and the normal changes in sexuality with age.

Despite modern advances in the understanding of libido and other aspects of sexuality, pharmacological treatment options remain limited. Androgen replacement is often recommended, and a transdermal patch that releases the hormone testosterone via the skin into the bloodstream is available, although only in Europe. Currently, there are no testosterone preparations licensed in the USA.