Sexual dysfunction and associated factors in Thai patients with psychiatric disorders

Study population

This was a cross-sectional study. We enrolled out-patients aged 18 and older who visited the psychiatry clinic at King Chulalongkorn Memorial Hospital, a quaternary teaching hospital in Bangkok, Thailand between August 2020 and December 2021. Each patient selected could freely decide if they wished to join the study; written informed consent was obtained for those who agreed to participate. Inclusion criteria for study participation were being at least 18 years of age, able to communicate in Thai, and having a diagnosis of depressive disorder, bipolar disorder, anxiety disorder, or schizophrenia. Exclusion criteria were an unstable medical or psychiatric condition or an impaired ability to communicate. Demographic and clinical data were assessed, and sexual dysfunction was diagnosed by a sole psychiatrist using the clinical interview for the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Adequate sample size was determined by the Cochrane formula, and convenience sampling was used. Through our study, 202 participants were invited to participate and none of them refused to join or was excluded from the study. The flowchart of participants' enrolment is shown in figure 1.

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Demographic and clinical data

Demographic and clinical data included sexual identity, age, body mass index (BMI), marital status, education, occupation and underlying medical issues. Psychiatric records were assessed for the diagnosis, duration of illness, the severity of symptoms, substance abuse, history of electroconvulsive therapy and psychotropic medications. All psychiatric diagnoses were based on the DSM-5.11 The dosage of all psychotropic agents was adjusted to the psychotropic dosage equivalence using the Anatomical Therapeutic Chemical as the classification system and the defined daily dose method.12 We used the second version of the Brief Psychiatric Rating Scale (BPRS), which comprises 18 items measuring multiple dimensions of psychiatric symptoms, and categorised them into two grades of severity with a cut-off score of 36.13 The 26-item Thai version of the World Health Organization (WHO) Quality of Life-BREF was used to measure the quality of life of all participants.14 Four domains of quality of life were assessed by the tool, including physical health, psychological health, social relationships and environmental health. The total score was positively correlated with better quality of life, and those with a score higher than 95 were considered to have a good quality of life.

Sexual dysfunction

Sexual dysfunction was diagnosed using diagnostic criteria from the DSM-5. According to the DSM-5, established diagnoses include male sexual dysfunctions (male hypoactive sexual desire disorder, erectile disorder, premature (early) ejaculation and delayed ejaculation), female sexual dysfunctions (female sexual interest/arousal disorder, female orgasmic disorder and genitopelvic pain/penetration disorder) and substance/medication-induced sexual dysfunction. To meet the criteria, neither medical conditions nor non-sexual mental disorders could explain the symptoms, and all sexual dysfunctions should cause significant functional impairment or individual distress. Thus, the diagnosis could not be made in those with symptoms who did not report impairment in function or significant distress. The sexual dysfunction history of all participants was assessed during a clinical interview conducted by a single psychiatrist to limit inter-rater bias.

Statistical analysis

Statistical analysis was conducted using the SPSS V.22.0 package program. Demographic and clinical data were presented in count and percentage, mean (standard deviation, SD) or median and interquartile range (IQR). Fisher’s exact test, unpaired t-test and Mann-Whitney U test were used for the univariate analysis as appropriate. Notable risk factors for sexual dysfunction and significant factors from the univariate analysis were entered into multivariable logistic regression analysis to determine the associated factors of sexual dysfunction. A p value <0.05 was considered statistically significant.

Main findings

Our results indicated an enormous but hidden burden of sexual dysfunction in Thai patients with mental disorders. Sexual dysfunction was slightly more prevalent in female than in male patients, consistent with findings from a previous study.15 However, the same study showed a greater prevalence of sexual dysfunction for both sexes (male 84.7%, female 95.7%), compared with our findings (male 47.3%, female 53.3%). Sexual dysfunction has ranged widely in prevalence (16.8%–70.0%) based on the methods for diagnosing sexual dysfunction used in each study or population with specific mental disorders.16–19 In Thailand, the prevalence of such conditions among psychiatric and non-psychiatric populations is understudied. Some previous findings reported the prevalence of sexual dysfunction in only specified sexual identity diagnoses, which were made using self-rated questionnaires.20 21 We used the clinical interview for DSM-5 as a diagnostic method, in which either functional impairment or individual distress is a necessary symptom. Thus, some patients with sexual dysfunction symptoms might not have been categorised as having sexual dysfunction since the essential criterion was absent. In addition, most patients were single and, thus, may be less impacted by sexual dysfunction symptoms than those in coupled relationships, so sexual dysfunction could not be diagnosed.

No significant association between sexual dysfunction and psychiatric diagnosis was found. Sexual dysfunction occurred in approximately half of the patients with the enrolled diagnoses (depressive disorder, schizophrenia, anxiety disorder and bipolar disorder). Sexual dysfunction may be overlooked in some patients with social impairments, such as those experiencing the negative symptoms of schizophrenia; nevertheless, the dysfunction is prevalent in this group, and screening is recommended.22 Therefore, sexual dysfunction should be considered in all patients regardless of their psychiatric diagnosis. Also, substance use was not associated with sexual dysfunction. Strong evidence of negative sexual consequences from the use of alcohol and tobacco was lacking.23 Some substances of abuse, methamphetamine in particular, could enhance sexual pleasure and might be used as self-medication for sexual dysfunction.24 The effect of alcohol, which shares a similar pathway with benzodiazepines, impacted sexual health bidirectionally,25 26 and the exact effects of such substances in clinical settings were hard to conclude. Therefore, further studies are needed. However, the onset of sexual dysfunction may either precede or follow psychiatric disorders, and causality cannot be presumed according to our study design.

To the best of our knowledge, the association between employment and sexual dysfunction has not been widely mentioned in previous studies, whereas the poorer quality of life has been notably linked with sexual dysfunction.27 28 For vulnerable populations, including patients with psychiatric disorders, being employed was a strong protective factor against the poor quality of life29 and could explain the lower sexual dysfunction in those employed or their reporting better quality of life. Additionally, both sexual health and occupational functioning were measured by the tool used to assess the quality of life.14 Correlation between these factors was solid, and improving employment or quality of life might promote sexual function. However, a causal relationship between sexual dysfunction and such factors could not be assumed due to our study design.

Our results showed a significant correlation between sexual dysfunction and the dosage of antidepressants and benzodiazepines in the negative direction. Antidepressants are remarkable for their sexual side effects30 31 and the dosage of prescribed antidepressants is one crucial factor.32 Sexual dysfunction, including erection, orgasm and ejaculation problems, was frequent among those using benzodiazepines, especially with higher dosages of the drug. To the contrary, increased desire or sexual disinhibition was commonly found when low-dose benzodiazepines were used.25 26 Thus, though lower dosages of benzodiazepines seem to promote sexual function, sexual dysfunction becomes more common with increasing dosages of benzodiazepines, as reported in our study; determining the safe dosage of benzodiazepines for sexual dysfunction prevention is worth studying. Interestingly, a greater proportion of those having sexual dysfunction in our study used antipsychotic agents, but this finding did not reach statistical significance. The antipsychotic dosages given to our study's subjects were rather low and might not be related to sexual dysfunction because the latter requires a higher dosage of antipsychotic agents to produce the side effect. This phenomenon has to do with dopamine activity and prolactin levels, which might also differ in male and female patients.33 34

Though age was not significantly associated with overall sexual dysfunction, our study found higher age to be one predictor for erectile disorder and female sexual interest/arousal disorder. Declination of erectile function and female sexual desire due to ageing was also shown in other studies,35 36 and clinicians were recommended to screen for these two specific sexual dysfunctions in older patients. Also, patients with erectile disorder seemed to report lower quality of life, which was consistent with several previous studies.37–39 We believe self-esteem played a major role in linking poorer quality of life with sexual dissatisfaction or erectile dysfunction, especially if combined with psychogenic aetiologies,40 and explained the similar finding among patients with male hypoactive sexual desire disorder. The association between psychotropic medication use and some specific sexual dysfunctions was also noted. Our study confirmed the relationship between antidepressant dosage and delayed ejaculation.41 Apart from this well-known linkage, we emphasised that higher dosages of benzodiazepines are associated with female orgasmic disorder and sexual desire disorder in both male and female patients. Commonly prescribed in the psychiatric unit, the dosage of benzodiazepines should be optimised for minimal side effects and maximum benefit. An investigation focusing on this category of medications would be beneficial.

Our study is the first to report the prevalence of sexual dysfunction among Thai patients with mental disorders. Our results highlight the obscured magnitude of sexual dysfunction that may exist among those with psychiatric disorders, though generally, it may go undetected because it is under-reported by patients and under-evaluated by clinicians. We used the clinical interview for DSM-5, the gold standard for diagnosing sexual dysfunction, as assessed by a sole psychiatrist to ensure the accuracy of sexual dysfunction diagnosis and limit inter-rater bias. Multidimensional factors were recorded and analysed.

Limitations

Some limitations should be mentioned. The DSM-5 diagnosis of sexual dysfunction includes impairment in function or significant distress to the individual, so those with sexual dysfunction symptoms were not classified as having sexual dysfunction in our study unless these criteria were fulfilled. Our sample size was rather small, and we conducted this study in the outpatient psychiatric department of one university hospital in the metropolitan region of Bangkok. Thus, the generalisability of our results might be limited to patients with less severe symptoms or those living in urban areas. In addition, our study was a cross-sectional design and could not explain causal relationships between sexual dysfunction and associated variables. There was no control group taken from the general population. Future studies should have a greater sample size and be conducted using a prospective cohort. Studies using standardised sexual dysfunction self-rated screening tools should evaluate them for their psychometric properties and their feasibility for implementation in clinical settings, especially in countries where sexual issues are taboo for discussion and psychiatrists are lacking.

Implications

Sexual dysfunction among this population of Thai patients with psychiatric disorders was relatively high and could likely be even higher given that many patients did not meet the criteria for a formal diagnosis. Further studies should investigate how to improve patients' quality of life and optimise prescription dosaging.