Psychotropic drug-induced sexual function disorders: diagnosis, incidence and management

The human sexual response can be divided into 3 phases: desire (libido), excitement (arousal) and orgasm. The fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) classifies sexual disorders into 4 categories: (i) primary; (ii) general medical condition-related; (iii) substance-induced; and (iv) 'not otherwise specified' sexual dysfunctions. Each of the 4 DSM-IV categories has disorders in all 3 sexual phases. Substance-induced sexual dysfunctions are caused by the use of either substances of abuse [alcohol (ethanol), amphetamines, cocaine, opioids or sedatives/hypnotics/anxiolytics], or prescription medications which include psychotropic drugs. Patients with psychiatric difficulties tend to experience more frequent sexual function disturbances. The literature provides more than anecdotal evidence that psychotropic drugs can induce sexual function disorders in the epidemiologically vulnerable population of psychiatric patients. Sexual dysfunctions caused by psychotropic drugs can be divided into 2 groups: sexual inhibition (inhibited desire, inhibited arousal and inhibited orgasm) and increased sexual function disorders (increased sexual desire, priapism and premature ejaculation). The diagnosis of psychotropic drug-induced sexual function disorders is easy if the psychiatrist is sensitive to the existence of these adverse effects. This mostly involves careful history taking, although several questionnaires have been developed for reliable and valid quantification of sexual functioning. Diagnosis is usually established if the sexual function disorders develop when the patient is receiving a psychotropic drug and then disappear when the offending drug is discontinued. The management of psychotropic-drug induced sexual inhibition can be divided into 6 steps: inform the patient about the possibility of sexual inhibition occurring before prescribing a psychotropic agent; wait for remission or tolerance of sexual inhibition; reduce the dosage of the psychotropic drug; switch the medication to one less likely to cause sexual inhibition; if possible, adjust the concomitant nonpsychotropic drugs; and add various pharmacological agents to the existing psychotropic drug to treat the sexual inhibition. Physicians should take sexual histories as a routine practice when prescribing psychotropic drugs. Through careful management and patience on the part of both the patient and the physician, psychotropic drug-induced sexual function disorders can be improved so that the patient's compliance with medication and quality of life can be optimised.