Figure 1
Cerebrospinal fluid (CSF) concentrations of interleukin-1β (IL-1β) in male euthymic bipolar disorder patients (data set I) and healthy controls. (a) Mean CSF IL-1β concentration (±s.e.m.) in 30 healthy male volunteers (0.79±0.044 pg ml−1), 16 bipolar disorder patients without a history of psychosis (3.06±0.58 pg ml−1) and 11 bipolar patients with a history of psychosis 5.35±0.71 pg ml−1. One-way analysis of variance (ANOVA) with Tukey’s post hoc tests, P<1 × 10−6; post hoc tests: controls vs nonpsychotic bipolar patients, P=6 × 10−5; controls vs psychotic bipolar patients, P<1 × 10−6; and nonpsychotic bipolar vs psychotic bipolar patients, P=0.020. (b) Of these patients, 16 carried out the trail making test (TMT). Nine patients scored ≥10 (mean standard score) and 7 scored <10. The median CSF IL-1β concentration was higher in the group with more difficulties in set-shifting (5.84±2.89 pg ml−1 (median±interquartile range)) compared with the group that scored ≥10 (1.96±2.68 pg ml−1, Mann–Whitney U-test, P=0.012). (c) A possible confounding effect of peripheral inflammation was assessed with correlation analyses. Increasing CSF IL-1β concentration was associated with difficulties in set-shifting (rs (Spearman)=−0.53, P=0.034), also when adjusting for high-sensitivity C-reactive protein (hsCRP) concentration (rs=−0.59, P=0.021). Error bars represent mean±s.e.m. in (a) and in (b) median with third quartile. Two-sided P-values, statistical significance set to P<0.05. *P<0.05, ****P<0.0001.
