The sexual desire and the problems of sexual desire are an area of concern for clinicians since a long time, particularly since mid 1970's. Many authorities have emphasized the psycho-bio nature of the desire phenomenon, that it precedes and accompanies sexual arousal and on the whole generates sexual behaviour. It results from the complex interaction between sexual drive, sexual wish, willingness or aspiration and the sexual motivation. The wish or the aspiration and the motivation are the psychological-cognitive and emotional components while the sexual drive is primarily a biological component, being a neuro­endocrine generator of sexual impulses. The force of the drive is generally being accepted as an appetite like hunger or thirst. Like them, the neuro-physiological basis of sexual desire lies in the limbic system. Clinically various degrees of the sexual drive have been recognised. It could be high, moderate, low or absent (Agarwal and Katiyar, 1994). It tends to establish its own level and changes predictably in relation to one's sex, age, nature of up bringing, quality of current relationship and other environmental factors.

This manifests as a periodic and spontaneous need for an orgasm. The genital excitement could be recognised by genital tingling, tumescence or lubrication, nocturnal emissions, erotic dreams, partner seeking behaviour, masturbation and erotic fantasies. The wide variation in arousal and excitability is well recognised. Many couples know the frustration when one feels like having sex while the other would rather turn and sleep. Some people seem to be interested in sex at almost anytime, while others have low or lack of any sexual interest. For the same, since nobody can define a 'normal sex life'. Masters and Johnson insist that desire disorder is present when it leads to marked or significant "personal or relational distress". Having sexual urges, fantasies and activity less than twice a month have been defined as a low sex drive but at best these definitions are quite arbitrary and controversial.

DEFINITION

The terms like 'Libido', 'Urge', 'Passion', 'Hominess', 'Impulse', 'Need', 'Instinct', etc. have been used interchangeably for desire. However, these terms are more explanatory than descriptive and can create confusion. Hence, it is preferable to use the term 'SEXUAL DESIRE' as such. Levine in his review recognises that despite the concentration of clinical work and writings on sexual desire disorders, hardly any worth while attempt has been made to define it.

The most accepted definition could be that "sexual desire is a psycho-biologic energy that precedes and accompanies arousal and it tends to produce sexual behaviour". It fluctuates in frequency and intensity all through one's life.

The sexual response cycle as reported by Masters and Johnson had recognized 4 phases - excitement, plateau, orgasm and resolution. DSM-IV classification of American Psychiatric Association recognises the Desire or Appetitive phase as a distinct stage in the response cycle (Fig. 1). So also disorders of this stage are explicitly recognised as such. The excitement stage includes both the excitement and plateau phases described by Masters and Johnson. In the desire phase, the emphasis is on various sensory stimuli like visual (by far the strongest), olfactory or tactile and or the fantasies.

EPIDEMIOLOGY

Clinically, the individuals or couples may present with little or too much of sexual desire and at present they constitute the most frequently seen sexual problems. Levine opines that many conditions diagnosed as arousal problems in earlier decades are currently viewed as problems in the desire phase of the sexual response cycle.

ICD.10 recognised excessive sexual drive as a condition but it is more a theoretical concept than an actual observation in practice. It is said that a woman with a voracious sexual appetite is a Nymphomaniac while in man it is "Don Juanism". Sexual addiction or sex addiction, a term used by Patric Carnes, is a relative phenomenon and indicates an unhealthy obsession with sex. Much of the research data we have is from western studies. Frank et al (1978) surveyed 100 well educated and married couples and reported that 50% of men and 77% of women had lack of interest in sex and were unable to relax. Nathan (1986) analyzed 22 general population sex surveys to estimate the prevalence rates for various sexual dysfunctions. 1 to 15% of men and 1 to 35% of women had desire disorders, mainly that of reduced sexual desire. Bechtel and Stains (1996) showed that low sexual desire is the main complaint of upto 55% of couples who show up at sex therapy clinics, making it the most common sexual complaint of all. Research has also demonstrated that it is drastically increasing in the last 20 years. This had been attributed to the fact that women's new found liberation and aggressiveness is a turn-off to many men. it is also possible that society and media generated a hype that everybody is having sex and nothing but sex that is frequent. Hence, the social pressure to be a superman and when the ideal is not met, people tend to define it as a problem. In the Indian context a retrospective comparative study of hospital and clinic population of 2 years by the author and colleagues (99) showed desire disorders being significantly higher in females than in males.

DEVELOPMENT OF SEX DRIVE

Biologically, sex drive is determined by periodic production of neuro-endocrinal impulses from the limbic systems. This process in both males and females is dependent on the circulating levels of androgens. The hormone primarily responsible for the desire in both the sexes is testosterone. It is known that only 5% of testosterone, which is in free form is physiologically active that the circadian rhythm of testosterone release is such that level is gradually increasing during sleep to reach a maximum towards early morning. Freud believed that girls centered their sexual pleasure in their clitoris during pubertal stage and with maturity they switched it to vagina. Kinsey, Masters and Johnson, Shere Hite and other sex researchers have shown that no such change takes place. Clitoris remains the focus of female libido and is not indicative of any immaturity.

MALE AND FEMALE SEX DRIVE

Men have a stronger overt sex drive and are more open in their desire for sexual contact than women. The important physical and social reasons are as follows :

1. For men, orgasm and intercourse are inevitably linked. For a man, intercourse invariably leads to orgasm, hence pleasure and therefore he seeks it more frequently.
2. It is socially acceptable for men to enjoy and want sex. Men with great sexual prowess as legendary Casanova have become great heroes.
3. Men are expected to be lustful and those who show disinterest in the opposite sex are treated with suspicion.
4. Upbringing teaches males to be interested in sex - many parents worry about sons who are reluctant to go out with girls, at least in western culture.

1. Many women find it difficult to achieve orgasm. Rather this appears perfectly normal. In her, achieving orgasm does not come through intercourse alone but is achieved by skilled love making and the stimulation of sensitive areas such as clitoris. Unless a woman has a partner who understands this, for her orgasm is impossible. Therefore, intercourse does not automatically mean intense pleasure to woman as to a man. So- many women do not seek it enthusiastically resulting in lower sex drive.
2. Women suffer less from sexual frustration in diversions like sentimentality, romance, love, etc.
3. Girls are actively discouraged interacting with boys, particularly in traditional societies like ours.
4. Very few parents teach daughters that sex is a joyous, pleasurable thing. It is taught as a duty, what men need and that women have to tolerate.
5. Social attitudes where sensuality in women is invariably branded as 'loose' etc.
6. Physiologically, there is a significant cyclical hormonal fluctuation in women. This results in a variable sexual drive.

CLASSIFICATION OF DESIRE-PHASE DISORDERS

The decrease in sexual desire is the commonest clinical presentation. Hyperactive sexual desire disorder is primarily of research importance. It is to be emphasized that in the desire-phase disorders the capacity for physical sexual response is usually preserved and the problem is one of lack of willingness to participate in sexual relations due to either fear or lack of interest (Masters and Johnson, 1986). If the lack of interest is the predominant problem, it is classified as Hypoactive sexual desire disorder (Table 2). If the lack of participation is mainly due to overwhelming fear it is referred to as Sexual aversion disorder (Table 3). Like other sexual dysfunctions they could be life long or acquired type. They could be (a) generalized or (b) situation specific i.e. they occur only in a certain context, with a particular partner etc. It could be due to psychological factors or due to combined factors where pathology is invariably multifactorial. Biological factors may be secondary to general medical condition or due to a particular substance abuse.

As gender role discrepancies are well recognized, if sexually active partners consistently describe different appetites for sex and are unable to compromise, Bancroft (1983) labels the problem as sexual dissatisfaction instead of sexual disorder and is diagnosed as 'Desperate levels of sexual interest'. The term ISD is reserved for those situations of abnormally low libido in which an aetiologic diagnosis has been made i.e. when it is established that sexual desire is inhibited by psychic factors. The term HSD is preferable when the aetiology of low libido has not yet been determined. The diagnosis of Hypoactive or inhibited sexual desire disorder is used only when an individual evidences low initiatory behaviour and or a persistently negative receptivity to sexual approaches by an established partner. Frequency of sexual encounter is avoided as a diagnostic standard due to its changes with age and health. Masturbatory behaviour and sexual fantasy are reliable indicators, if at all, only in cases of hypogonadism.

Table 2 : DSM-IV Diagnostic Criteria for Hypoactive Sexual Desire Disorder

1. Decreased testosterone levels.
2. Decreased L.H.R.H.
3. Decreased thyroid hormones.
4. Increased, prolactin levels.
5. General medical conditions like cardiac, renal, respiratory and other chronic, severe illnesses. Other endocrine disorders like diabetes mellitus etc.
6. Medications which block dopamine receptors such as anti-psychotics, medicines which elevate serotonin e.g. antidepressants, fluoxetine and others, antihypertensives, mood stabilizers like lithium and other drugs.
7. Neuro-psychiatric disorders, in particular depression, obsessive compulsive disorder, epilepsy, Parkinsonism etc.

B. PSYCHOLOGICAL FACTORS :

decreased self esteem, anger, hostility, guilt, anxiety secondary to other sexual dysfunctions, early conditioning, sexual trauma, fear of intimacy or separation, other relational issues like lack of trust, power and control issues, attitudes, religious and cultural beliefs, sexual ignorance and myths, absence of fantasies, distracting thoughts or antifantasy like harbouring fantasies incompatible with sexual arousal.

FACTORS WHICH INCREASE THE SEX-DRIVE

1. Mania, is the commonest cause
2. Alcohol, in the initial stages
3. Substances of abuse when used occasionally and in low doses.
4. Drugs which enhance dopamine functions such as L-Dopa, bupropion, etc.
5. Certain cerebral degenerative disorders, due to disinhibition and in certain types of epilepsies.

Depression is perhaps the most common physiologic cause of HSD. Depression is marked by a diathesis of vegetative symptoms which include sleep, eating and libido disturbances.

Severe stress such as is experienced on the battlefield or during a traumatic divorce or after a job loss is often associated with a loss of sexual interest.

APHRODISIACS

Aphrodisiacs are substances which are supposed to increase sexual desire. Oysters, powdered rhinoceros horn, Ginseng, animal testicles are a few of the common ones attributed to increase sexual desire. However, there is no established drug or miraculous potion which has such an established effect. At best these are harmless but at worst they can be dangerous. One aphrodisiac known as Spanish fly is a serious irritant which can be very damaging to sensitive urethral tissues. The so called aphrodisiac effect may be because of PLACEBO EFFECT.

The ideas that special foods, drugs or concoctions will arouse libido is a pure fantasy but there are certainly some human factors which increase sex drive. Being in love is the greatest stimulant many couple could ever hope to find.

TREATMENT

Among all the sexual dysfunctions desire disorders are the most difficult to treat.

A. HYPOACTIVE SEXUAL DESIRE DISORDER

1. Like sexual dysfunctions in general, many disorders of sexual desire arise because of basic sexual misinformation, lack of experience or destructive relational transactions (Masters and Johnson, 1986). These can be effectively treated by permission giving and educational components of sex therapy. Cognitive behaviour therapy helps alleviate maladaptive beliefs.
2. If spectator role and the performance anxieties are the main blocks, brief psychotherapy and behaviour therapies are to be carried out. Exercises to enhance sexual pleasuring like sensate-focus, non-demand sexual stimulation and improving communication are essential.
3. In presence of significant intimacy disorder long term psycho-dynamic psycho-therapy is advocated.
4. Relational problems need to be attended to by marital therapy.
5. Drugs.

a. Testosterone

the prostate.

        a.3 Normally, for the physiological effect, testosterone, has to be converted into dihydrotestosterone and                 subsequent aromatization to oestradiol. In normal men, circulating androgen levels are far higher than                 the threshold level required for physiological action. Hence, the endogenous variations or exogenous                 administration of   testosterone does not produce any demonstrable effect in sex drive.

        a.4 The androgens maintain sex desire and activity in women. Testosterone in minimal non-masculinizing                 dosages can be included with good therapeutic effect  in  post- menopausal women.

SEXUAL AVERSION DISORDER

Major goal of treatment is to reduce the patient's fear and avoidance of sex. In clinical practice they carry the worst prognosis.

1. Systematic desensitization - Patient is gradually exposed in imagination under relaxation and then in-vivo to the actual sexual situations which generate the anxiety.
2. Marital therapy to correct relational problems.
3. Psychotherapy - Brief and psychodynamic-oriented are beneficial.
4. Pharmacotherapy - Tricyclic antidepressants, particularly imipramine and benzodiazepines like Alprazolam are found to be very effective in controlling phobic anxiety.
5. Sex therapy using education, permission giving and improving communication is a must in all the cases.

Orgasm is characterised by feelings of heightened excitement, a peaking of subjective pleasure and subsequently release of sexual tension.
Women's orgasmic contractions may continue longer than those of men. Also, women can experience multiple orgasms in close succession, whereas men cannot. However, women's experiences of orgasm are quite varied.
Orgasm or sexual climax may be produced by stimulation of genital organs e.g. clitoris, vagina.
Orgasmic dysfunction or disorder (OD) refers to those women who are unable to achieve orgasm or have great difficulty in reaching climax in the presence of sufficient sexual stimulation.
Anorgasmia is the term synonymously used to indicate inability of the women to achieve orgasm.

Primary   -   the woman has never experienced orgasm.
Secondary   -   the disorder has developed after a period of being able to reach orgasm.

Situational - where she can reach a climax only under specific circumstances. Other synonymous terms used for orgasmic disorders is inhibited female orgasm. Prior to 1970, the term frigid was used to describe the women who did not respond with orgasm when stimulated sexually. Because this term is pejorative, it is no longer used.

Various aetiological factors may be responsible for producing this disorder. They are depicted in the following figure :