The results provide evidence that psychiatric disorders and risky sexual behaviour occur in the same people at age 21 with unusual prevalence. Although risky sexual behaviour and sexually transmitted diseases are common among this age group, a disproportionate burden is carried by those with psychiatric disorders. The associations were not moderated by sex. This effect does not seem to be due to social disadvantage in the family of origin because adjustment for socioeconomic background made no difference to the results. Even if the associations were partly mediated by other aspects of social or educational background, the primary association is important clinically. Young people with psychiatric disorder function with more difficulty in society than those without disorder.12
The damaging consequences to health of risky sexual behaviour, such as unplanned pregnancy and sexually transmitted diseases, compound the impairments those with psychiatric problems already experience. Psychiatric comorbidity, which occurs in half of psychiatric cases12,21
and is associated with increased risk of impairment,22
signals additional sociosexual risk.
Our results confirm previous findings of an association between sexual risk taking and externalising problems such as conduct disorder and substance abuse.5–7
The strongest association of risky sexual behaviour was with disorders characterised by disinhibition or a pattern of impulsive behaviour (for example, antisocial personality, mania, and drug and alcohol dependence). Two additional findings are noteworthy. Firstly, young adults who present with symptoms in the schizophrenia spectrum were more likely to take part in risky sexual intercourse, develop sexually transmitted diseases, and have sexual intercourse at an early age. Secondly, depression, the most common psychiatric problem in the population, was also linked with these three outcomes. Furthermore, depression combined with an antisocial disorder or substance disorder increased the risk. This link is noteworthy as rates of depression escalate from age 15 to 21 years,23
the period when sexual activity likewise emerges. About one third of people who use primary care services exhibit depressive symptoms.24
On the one hand, depressed young adults may engage in risky sexual behaviour (and substance abuse) because of feelings of hopelessness, worthlessness, and disregard for self or in an attempt to self treat their depression. On the other hand, harmful consequences from a sexual relationship may precipitate a depressive episode.
We did not assess the full spectrum of DSM-III-R disorders, making it possible that we underestimated the extent of concurrence of psychiatric disorders and risky sexual behaviour. We also examined the concurrence of psychiatric disorders and sexual behaviour cross sectionally. To inform prevention and intervention efforts, longitudinal analyses are needed to determine the temporal nature of this association, which may vary by disorder. Bad sexual experiences may lead to depression, but antisocial personality may lead to spreading sexually transmitted diseases.
To our knowledge this is the first report that establishes strong links between a wide range of psychiatric disorders and sexual behaviour. Prevalence and incidence rates of psychiatric disorders and sexual behaviour in the Dunedin sample are similar to those found among young adults in the United States and United Kingdom,12,20
thereby lending confidence to the generalisability of the data. The results show that the most common psychiatric disorders in young people (substance dependence and depression) are the disorders that are linked to sociosexual problems. The findings highlight the need to coordinate sexual medicine with mental health services in the treatment of young people. Awareness of this potential comorbidity may also assist with prevention strategies. Moreover, early detection will be facilitated if practitioners are aware that risky sexual behaviour may be associated with mental health problems.
What is already known on this topic
Onset of psychiatric disorders and risky sexual behaviour both peak in young adulthood
What this study adds
A disproportionate burden of risk and disease associated with sexual behaviour is borne by young people with psychiatric problems
Depression, substance dependence, antisocial personality, mania, and schizophrenia spectrum are associated with risky sexual behaviour and sexually transmitted diseases
Psychiatric comorbidity increases the likelihood of sexual risk taking