For the CVLT and WAIS-R, separate multivariate analyses of covariance (MANCOVA) with age, sex, education, duration of illness, and center as covariates were used.
However, there was no association between Stroop performance and subthreshold depression (as measured by the HAMD-21), subthreshold manic symptoms (as measured by the YMRS), years of education, duration of illness and number of hospitalizations (all p's > .05).05
Reaction times (left graph) and error rates (right graph) of patients without and with long-term lithium treatment and healthy controls adjusted for age, sex, education, duration of illness, and center, p < 0.001: $non-Li group vs. healthy controls, #Li group vs. healthy controls, §Li group vs. non-Li group.
WAIS-R subtest scores of patients without and with long-term lithium treatment compared to healthy controls adjusted for age, sex, education, duration of illness, and center dark to light blue: subtests of the verbal part, red to yellow: subtests of the performance part.
For the VBM data separate MANCOVA with repeated measurements with reaction time (MANCOVA 3) and error rate (MANCOVA 4) in the six ISI (14, 29, 43, 57, 86, and 114 ms) as dependent variables and age, sex, education, duration of illness, and center as covariates were applied.
This was completed by correlating time needed in the Stroop interference with six possible confounders available in our dataset, such as subthreshold depressive symptoms (as measured by the HAMD-21), subthreshold manic symptoms (as measured by the YMRS), years of education, duration of illness, number of hospitalizations and the FAST cognitive score.
Other aspects of the study have been described elsewhere.[16], [17] Data on age, level of education, duration of hypertension and treatment, history of cigarette smoking, current and past symptoms of cerebrovascular disease, peripheral vascular disease and coronary heart disease were collected by interview using a structured questionnaire.
The median education duration was 4.5 years (0-18 years).
It included questions regarding level of education, duration of employment, working settings, and professional rank.
Ethnicity, education, duration of working shift and working duration after controlling for age never reached significance.
The prevalence of obesity increased with the level of education (duration of education) in both sexes.
