Findings:
This controlled, population-based study used the Taiwan National Health Insurance Research Database to investigate the risk of adolescents and young adults acquiring sexually-transmitted infections (STI) following first-episode psychosis (FEP). The control group comprised age- and sex-matched individuals without schizophrenia. Findings included the following: Subjects with a new onset psychotic episode were at significantly increased risk of acquiring a sexually-transmitted infection compared to subjects without schizophrenia. Among the six STIs identified, FEP subjects were at highest risk for HIV, syphilis and gonorrhoea. When STI incidence rates among FEP subjects were compared to rates in controls subjects, rates of HIV and syphilis were disproportionately elevated. Having a comorbid alcohol use (AUD) or substance use disorder (SUD) further heightened the risk of STIs, especially HIV and syphilis, in FEP subjects compared to controls. Subjects with FEP and both AUD and SUD were at highest risk for acquiring HIV, when compared to other STIs in the FEP group. Injection drug use conferred an exceptionally high risk for HIV in the FEP group. Sub-group analysis of the FEP group demonstrated that the risk of HIV and syphilis increased in tandem with severity of schizophrenia, measured by number of hospitalizations. Subjects who were more adherent to treatment with anti-psychotic medications were less likely to acquire HIV or syphilis.

Strengths and limitations:
This study used a large, national, population-based database and included an age- and sex-matched control group. It also used a statistical analytic technique that supported causal evidence. This study was unique in its examination of the relationship between FEP and subsequent acquisition of STIs, especially HIV and syphilis. The study is limited by the lack of information about other possible contributing factors such as frequency of condom use, number of sexual partners and sexual identity. The measure for severity of psychotic illness used hospital admission rates as a proxy because the database did not provide direct measures of positive and negative symptoms. The effect of other variables known to influence behaviour among individuals diagnosed with schizophrenia, such as smoking status, personal lifestyle and sociodemographic status of the parents, could not be assessed. Due to geographical variability in patterns of STIs, findings may not be generalizable to other countries.

Relevance:
This study is highly relevant to clinicians and educators working at the intersection of psychiatry and HIV medicine. Early studies demonstrated an elevated HIV seroprevalence among individuals psychiatrically hospitalized for serious mental illness. This heightened risk was especially evident in those with comorbid substance use disorders. Since then, HIV prevention and treatment programs have been adapted to the unique needs of individuals with chronic mental illness. This study expands this area of HIV psychiatry by examining a subgroup of individuals who are vulnerable due to young age and distress accompanying new onset of a stigmatized mental illness characterized by impairments in judgment, neurocognitive function, medication adherence, interpersonal effectiveness and self-awareness and self-care. These challenges come at a time in their lives of enhanced sexual interest and behaviour, increased risk-taking and identity consolidation. Additionally, it is not surprising that comorbid substance use disorders, also common in younger individuals, further increases risk for HIV and other STIs. These findings add support to the utility of a syndemic framework for HIV prevention and treatment. This approach may guide development of targeted interventions such as medications for HIV pre-exposure prophylaxis, medications for SUDs, and antipsychotic medication adherence programs. A syndemic approach may also guide research related to the genetic underpinnings of schizophrenia, HIV, and SUD. Other areas for future investigation include how the neurobiology of risk behaviours in young adults differs from older adults, and how sexual behaviour among young individuals with psychotic disorders compares to those with other major psychiatric illnesses.                

Type of study:
This was a population-based cohort study using Taiwan’s National Health Insurance Research Database