Neurochemical aspects of the sexual response cycle

Transcranial Photobiomodulation Therapy for Sexual Dysfunction Associated with Depression or Induced by Antidepressant Medications

Sexual dysfunction (SD) is frequently encountered in patients suffering from depression. There is a bidirectional relationship between various types of SD and depression, so the presence or treatment of one condition may exacerbate or improve the other condition. The most frequent sexual problem in untreated depressed patients is declining sexual desire, while in treated depressed patients it is difficulties with erection/ejaculation and with orgasm. Numerous classes of neuropsychiatric medications, commonly used in depressed patients—such as antidepressant, antipsychotic, alpha sympathetic, and opioid drugs—may cause SD. Photobiomodulation (PBM) therapy, also called low-level light/laser therapy, is a novel neuromodulation technique for neuropsychiatric conditions, such as depression. Transcranial PBM (tPBM) targets the cellular metabolism—through the mitochondrial respiratory enzyme, cytochrome c oxidase—and has numerous cellular and physiological beneficial effects on the central nervous system. This paper represents a comprehensive review of the application of tPBM to SD, coexisting with depression or induced by antidepressant medications.

Benefits and risks of testosterone treatment for hypoactive sexual desire disorder in women: a critical review of studies published in the decades preceding and succeeding the advent of phosphodiesterase type 5 inhibitors

With advancing age, there is an increase in the complaints of a lack of a libido in women and erectile dysfunction in men. The efficacy of phosphodiesterase type 5 inhibitors, together with their minimal side effects and ease of administration, revolutionized the treatment of erectile dysfunction. For women, testosterone administration is the principal treatment for hypoactive sexual desire disorder. We sought to evaluate the use of androgens in the treatment of a lack of libido in women, comparing two periods, i.e., before and after the advent of the phosphodiesterase type 5 inhibitors. We also analyzed the risks and benefits of androgen administration. We searched the Latin-American and Caribbean Health Sciences Literature, Cochrane Library, Excerpta Medica, Scientific Electronic Library Online, and Medline (PubMed) databases using the search terms disfunção sexual feminina/female sexual dysfunction, desejo sexual hipoativo/female hypoactive sexual desire disorder, testosterona/testosterone, terapia androgênica em mulheres/androgen therapy in women, and sexualidade/sexuality as well as combinations thereof. We selected articles written in English, Portuguese, or Spanish. After the advent of phosphodiesterase type 5 inhibitors, there was a significant increase in the number of studies aimed at evaluating the use of testosterone in women with hypoactive sexual desire disorder. However, the risks and benefits of testosterone administration have yet to be clarified.

Erectile dysfunction and depression: screening and treatment

The comorbid conditions erectile dysfunction (ED) and depression are highly prevalent in men. Multiple regression analysis to control for all other predictors of ED indicate that men with high depression scores are nearly twice as likely to report ED than nondepressed men. Depression continues to be among the most common comorbid problems in men with ED, both in the community and in clinical samples. This article reviews the current knowledge about the relationship between ED and depression, the effect of treatments for depression on ED, ways to improve screening for depression, and treatment of ED in patients with this comorbidity.

Therapeutic targets for premature ejaculation

Premature ejaculation (PE) is the most common male sexual complaint, and may exert a profound negative impact on the man's life and partnership. Using currently available treatment alternatives (e.g., selective serotonin uptake inhibitor, agents acting locally on the penis), PE can be treated in most, but not all patients. However, since long term success rates have been disappointing, and the only approved treatment so far is the short-acting selective serotonin re-uptake inhibitor dapoxetine, there is currently an intensive search for new treatment modalities. Selection of the most promising therapeutic targets from a host of current and potential candidates depends heavily on their roles in the pathophysiology of PE. Possible central nervous targets that will be discussed are serotonin transporters, and CNS receptors for 5-HT(IA) and 5-HT(1B), dopamine, oxytocin, opioids, neurokinin-1, and glutamate. Putative peripheral targets include α(1)-adrenoceptors, phosphodiestrase enzymes, Rho kinases, purinergic (P2X) receptors, and penile sensory nerves. It is clear that exploiting the full therapeutic potential of these targets will require additional basic and clinical research.

Hypoactive Sexual Desire Disorder and Current Pharmacotherapeutic Options in Women

Hypoactive Sexual Desire Disorder (HSDD) is the most common female sexual dysfunction. The diagnosis of HSDD requires the existence of personal distress or interpersonal difficulties associated with low sexual desire, that cannot be explained by any other psychiatric affection and that is not exclusively due to a disease or substance. HSDD can have a serious effect on emotional wellbeing and interpersonal relationships, and it occurs in premenopausal and postmenopausal women. The Decreased Sexual Desire Screener is a shortened diagnostic method designed to help doctors who are not specialized in female sexual dysfunction to diagnose acquired HSDD in women. There is evidence that treatment with androgens or with estrogens is effective in HSDD; however, important unanswered questions still exist. Presently, new therapeutic strategies to combat HSDD are being researched, including novel methods of testosterone provision and drugs that act upon the CNS.

[Hypoactive sexual desire disorder, HSDD]

Hypoactive Sexual Desire Disorder (HSDD) is the most common Female Sexual Dysfunction (FSD) affecting adult women of any age, including postmenopausal women. HSDD may have significant effects on the relationships and emotional balance of women and constitutes the most common form of FSD observed in clinical practice. HSDD is characterised by a deficiency or lack of sexual fantasies and desire for sexual activity, causing serious distress or interpersonal difficulties, and it is not exclusively caused by the effects of another psychiatric disorder, pathology or substance (such as medication). HSDD pathophysiology is not yet well understood, but it is thought to involve an imbalance between factors controlling inhibition and excitation of sexual desire in the brain. Many physicians are reluctant to discuss sexual desire problems with their patients for various reasons, such as insufficient knowledge of the field, an absence of efficient treatments and time constraints. Even though current treatment options are limited, a better understanding of the physiopathology behind HSDD may help develop new therapies.

Sexual dysfunction associated with antidepressant therapy

Increasing numbers of patients are on psychiatric drugs, especially antidepressants. When patients complain of sexual dysfunction, it is important that the clinician take a careful history concerning psychopharmacologic agents. It is possible that simple interventions may maintain the desired effect of the psychiatric drugs while also eliminating sexual side effects caused by these agents.

Epidemiology and neurobiology of female sexual dysfunction

INTRODUCTION

Although several conceptual frameworks for female sexual dysfunction (FSD) have been advanced, there still is considerable disagreement over what constitutes a normal vs. abnormal response. Sexual dysfunction is a disturbance in sexual functioning involving one or multiple phases of the sexual response cycle or pain associated with sexual activity, while a sexual disorder includes both dysfunction and marked distress.

AIM

Review the literature regarding the epidemiology and neurobiology of FSD.

METHODS

Review of the literature.

RESULTS

While a wide range of epidemiologic studies has been published, it is still difficult to determine the scope of FSD and sexual disorders in the general population. It is becoming clear that good sexual health is associated with good physical and mental health as well as compatible relationships with one's sexual partner. Central nervous system (CNS) control of the sexual response is a relatively new area of scientific exploration.

CONCLUSIONS

We are improving our understanding of the contributions of the CNS neuroendocrine and neurotransmitter systems that modulate sexual behavior.

Botanical therapies in sexual dysfunction

Sexual dysfunction is a serious medical and social symptom that occurs in 10%-52% in men and 25%-63% in women. Numerous central and peripheral neural circuits control sexual activity. Impairment of one or more of these functional circuits may have a significant impact on personal, social and biological relationships. Although several aspects of sexual motivation and performance are known, a complete picture of the various factors that control human sexual activity is still unknown. The available drugs and treatments have limited efficacy, unpleasant side effects and contraindications in certain disease conditions. A variety of botanicals are known to have a potential effect on the sexual functions, supporting older claims and offering newer hopes. This review, while evaluating various factors that control sexual function, identifies a variety of botanicals that may be potentially useful in treating sexual dysfunction.

Menstrual cycle-related changes in plasma oxytocin are relevant to normal sexual function in healthy women

Circulating levels of the neuro-hypophysial nonapeptide oxytocin increase during sexual arousal and orgasm in both men and women. A few studies have evaluated the effect of the menstrual cycle on plasma oxytocin in normally cycling, sexually active, healthy fertile women using or not using contraceptive pills. In 20 ovulating women and 10 women taking an oral contraceptive (group 1 and group 2, respectively), sexual function, hormonal profile, and plasma oxytocin (OT) were evaluated throughout the menstrual cycle. In group 1, plasma OT was significantly lower during the luteal phase in comparison with both the follicular and ovulatory phases. Plasma oxytocin was significantly correlated with the lubrication domain of the Female Sexual Function Index (FSFI) during the luteal phase and showed a trend towards statistical significance during the follicular phase. In group 2, plasma OT did not show any significant fluctuation throughout the menstrual cycle, even though a significant correlation was evident with both the arousal and the lubrication domain of the FSFI during the assumption of the contraceptive pill. These findings suggest that plasma OT fluctuates throughout the menstrual cycle in normally cycling healthy fertile women with adequate sexual activity but not taking any oral contraceptive pill. Moreover, plasma OT levels significantly relates to the genital lubrication in both women taking and not taking oral contraceptive pill apparently confirming its role in peripheral activation of sexual function.

Bupropion sustained release for the treatment of hypoactive sexual desire disorder in premenopausal women

Premenopausal women meeting operational criteria for idiopathic, acquired, global hypoactive sexual desire disorder were studied in a randomized, double-blind, placebo-controlled, multiple-site escalating dose 112-day trial of bupropion sustained release. Outcome was measured by investigator-rating and self-administered questionnaires. All measures indicated greater sexual responsiveness in women receiving bupropion. The Changes in Sexual Functioning Questionnaire indicated that bupropion had significant effects on increasing measures of sexual arousal, orgasm completion, and sexual satisfaction.

Sexual dysfunction with psychotropic drugs

Sexual dysfunction caused by psychotropic medications has become an increasingly important clinical topic. Only recently have we acknowledged the extent to which many psychotropic medications, especially antidepressants and antipsychotics, cause sexual side effects. Prevalence rates of sexual side effects are extraordinarily difficult to estimate due to a variety of factors, such as the effect of the disorder being treated, comorbid disorders and baseline sexual dysfunction. Among the antidepressants, those with strong serotonergic properties have the highest rate of sexual side effects. Among the antipsychotics, those with greater D(2) blockade leading to increased prolactin levels are probably associated with more sexual dysfunction. Treatment approaches have been poorly developed for both antidepressants and antipsychotics. Antidotes for antidepressant-induced sexual dysfunction include bupropion, buspirone and sildenafil.