In addition to the psychological issues noted earlier, a thorough evaluation of ED should identify any underlying mental health problems. These mental health problems range from mild (e.g., temporary depression) to serious (chronic schizophrenia). Not only are mental disorders related to increased incidence of ED, but medications for mental conditions may also contribute to the development and/or maintenance of ED. Research on the comorbidity of sexual dysfunctions in men with a variety of mental health problems indicates that they are more likely to present with ED than men without such conditions. Anxiety has been associated with ED for many years, beginning with Masters and Johnson. As discussed earlier, anxiety during the sexual encounter is a major cause of ED.
Individuals with a variety of anxiety disorders, including social phobia, obsessive–compulsive disorder and posttraumatic stress disorder, manifest higher rates of sexual disorders, including ED. Depression has long been associated with sexual problems. In fact, the loss of sexual desire is considered one of the most common symptoms of depression. In men with serious depression, the incidence of ED can be as high as 90%. Depression has also been shown to be associated with reduced nocturnal erectile capacity, highlighting an underlying biochemical connection between depression and ED. Psychiatric treatment of depression, however, is also frequently associated with ED. A largescale study found that 37% of patients on antidepressant medications manifested a sexual disorder. While the most common sexual side effects of antidepressants are inhibited orgasm and decreased libido, the prevalence of ED is also higher in men taking these medications. All classes of medications for depression have been implicated in ED, but it is most common for selective-serotonin reuptake inhibitors (SSRIs). It is often unclear, however, whether the ED is the result of the illness or the treatment, so both must be considered.
Both treated and untreated men with schizophrenia demonstrate increased incidence of ED and those on antipsychotic treatment show greater difficulties. It is difficult to separate the various possible factors that may link schizophrenia to ED, which include the disorder itself, the medications used to treat it, and the psychosocial impact of the illness on the ability to develop sexual relationships. Unfortunately, men on antipsychotics may discontinue their use because of the perceived sexual side-effects.