Clinically observable features of the normal human sexual response cycle consist of four stages:

Patients (or their partners) may complain of decreased sexual desire or of one or more specific abnormalities of the response cycle or both. The dysfunctions may be situational, partial rather than complete, and primary or acquired. The phases usually occur in a stepwise fashion, but that is not mandatory—identify the stage involved. Often marital problems, unrealistic expectations,
long-standing personal “hangups,” and chronic difficulty establishing and maintaining intimate interpersonal relations are found. Identify these through history and psychiatric evaluation. Always evaluate carefully for organic causes (particularly with impotence and dyspareunia). Organic conditions tend to be chronic and independent of the situation.

Treatment should be global with an emphasis on intimacy and relationship, not just technique (1). Identify and treat psychosocial causes with dynamic psychotherapy, marital therapy, hypnotherapy, and group therapy. Sedatives may help temporarily if anxiety is prominent. Even purely physical causes often have significant associated secondary interpersonal problems that must be addressed once the medical condition has been corrected. A good prognosis is associated with acute recent dysfunction in a psychologically healthy patient with good past sexual functioning and strong sexual interests. Some relationships between partners are sufficiently hostile and destructive that unless other matters are resolved, prognosis is very poor for a correction of the psychosexual dysfunction.

The “new sex therapy” (Masters and Johnson) uses individual psychotherapy, couples therapy, education, behavior-modification techniques, and often a male-female therapist pair (dual-sex therapy). Their numerous techniques have wide applicability with sexual dysfunctions and should be considered for use. Many of these methods center on decreasing a patient’s (or couple’s) anxiety about making love. Essential principles include the following.

Men have impotence: a persistent or recurrent failure to reach or maintain a complete erection (2). Two psychogenic forms exist: in primary impotence, the patient has never maintained an erection,
and in secondary impotence, the patient has lost the ability—this may be person or situation specific (selective impotence). Moreover, biologically induced erectile disorder is the most common sexual dysfunction caused by SEXUAL DYSFUNCTION DUE TO A GENERAL MEDICAL CONDITION (DSM, p. 558) or SUBSTANCE-INDUCED SEXUAL DYSFUNCTION (DSM, p. 562), although several other sexual problems can have an organic etiology as well.

Impotence is a common sexual complaint of men, predominantly the secondary form. It is not a “natural consequence” of aging but does increase with age (6% to 8% of men in their 20s; 50%⁺ in men older than 70). Perhaps 50% are psychogenic, with an organic etiology more common with age. Organic causes include these:

Psychogenic causes include depression, anxiety (over cardiac status, performance, etc.), schizophrenia, hostility and marital conflict, etc.

First identify any physical cause. Do a complete medical evaluation (look for physical illness, absent beard and body hair, small testes, gynecomastia), and get serum testosterone (then further hormonal studies if low). Early morning sleeping erection or occasional successful intercourse does not rule out an organic etiology, nor does a normal pattern of nocturnal penile tumescence (NPT; erections during REM sleep) rule in a psychogenic etiology, although most psychogenic cases have normal NPT. Treat medical causes (often curative). Follow with couples or global therapy or both, if needed.
Therapy includes allowing the female to play the dominant role and insisting on a gradual shift from foreplay to intercourse.

Effective pharmacologic therapy has recently become available. The erect penis depends on the increased blood flow in the corpus cavernosum that is encouraged by increased local levels of cGMP elevated in response to sexual arousal. A new class of medication, the phosphodiesterase type 5 (PDE5) inhibitors, slows the degradation of cGMP by PDE5 in the penis and thus encourages blood flow to that organ. The first of the three such active drugs available was sildenafil (Viagra). Begin with 50 mg of sildenafil p.o. 1 hour before sexual activity. It starts working in about 30 minutes and lasts for about 4 hours. Use a maximum of 100 mg in 1 day. Side effects include primarily flushing (face), headache, and dyspepsia. Do not take with nitrates (i.e., be careful with the elderly heart patient who wants help with his impotence), and take care with any medications that inhibit the cytochrome P-450 isoenzyme 3A4 (primary metabolizer of sildenafil). Two other similar medications are vardenafil (Levitra; also lasts 4 hours) and tadalafil (Cialis; lasts for 24 to 36 hours). What advantages they may have, if any, over sildenafil is not yet clear.