Acutely ill psychiatric inpatients and antimicrobial exposure.

BACKGROUND

Patients with schizophrenia, bipolar disorder, and major depressive disorder (MDD) have increased infections. We explored the association between recent antimicrobial exposure and acute psychiatric illness.

METHODS

We performed a retrospective chart review of 267 acutely ill patients age 18 to 65. There were 92 patients with schizophrenia, 42 with bipolar disorder, 61 with MDD, and 72 with alcohol use disorders (hospitalized controls). Recent antimicrobial exposure was defined as occurring within 3 days of psychiatric hospitalization.

RESULTS

The prevalence of recent antimicrobial exposure was significantly increased in acutely ill patients with schizophrenia (16%), bipolar disorder (21%), and MDD (18%) compared with patients who had alcohol use disorders (4%, P ≤ .01 for each). After controlling for potential confounders, participants with schizophrenia or mood disorders were 5 to 7 times more likely to have recent antimicrobial exposure than participants with alcohol use disorders (schizophrenia: odds ratio [OR] = 4.5, 95% confidence interval [CI] 1.0-21.0, P = .053; bipolar disorder: OR = 6.9, 95% CI 1.3-35.7, P = .022; MDD: OR = 5.7, 95% CI 1.2-28.3, P = .032). Among participants with mood disorders, the association was stronger for participants with depression and affective psychosis compared with participants with alcohol use disorders.

CONCLUSIONS

We found an increased prevalence of recent antimicrobial exposure in acutely ill patients with schizophrenia and mood disorders. The findings provide additional evidence that infections are relevant to acute psychiatric illness.