Background: Markers of immune activation have been associated with mania but have not been examined in combination. We studied the association between mania and an inflammation score based on four immune markers.
Methods: A total of 57 individuals with mania were assessed at up to three time points: the day of hospital admission, evaluation several days later, and six-month follow-up. Also assessed were 207 non-psychiatric controls and 330 individuals with recent onset psychosis, multi-episode schizophrenia, or bipolar disorder depression. A combined inflammation score was calculated by factor analysis of the levels of class-specific antibodies to the NR peptide of the NMDA receptor; gliadin; Mason-Pfizer monkey virus protein 24; and Toxoplasma gondii. Inflammation scores among groups were compared by multivariate analyses. The inflammation score of the mania group at evaluation was studied as a predictor of re-hospitalization in the follow-up period.
Results: The combined inflammation score of the mania group at hospital admission and at evaluation differed significantly from that of the non-psychiatric controls (t=3.95, 4.10, p<.001). The inflammation score was significantly decreased at six month follow-up (F=5.85, p=0.004). There were not any significant differences in the inflammation scores of any of the other psychiatric groups and that of the controls. Within the mania group, an elevated inflammation score at evaluation predicted re-hospitalization (Hazard ratio=7.12, p=.005).
Conclusions: Hospitalization for mania is associated with immune activation. The level of this activation is predictive of subsequent re-hospitalization. Interventions for the modulation of inflammation should be evaluated for the therapy of individuals with mania.