Lithium and cognition: meta‐analysis

Bipolar disorder has been associated with cognitive impairment but it has been unclear what the contribution of medication may be. US investigators tackled the problem with a metaanalysis. They looked at 12 double‐blind trials (from a possible 586 publications) in 539 healthy volunteers or patients (n=326) reporting the cognitive effects of lithium (J Clin Psychiatry 2009;doi:10.4088/ JCP.08r04972). Among patients, the mean duration of lithium use was 3.9 years and the mean serum concentration was 0.82mEq per litre. In volunteers, mean lithium exposure was 2.5 weeks and the mean serum level was 0.78mEq per litre.

Lithium was associated with statistically significant but ‘mild’ impairment of creativity and immediate verbal learning and memory. There were no effects on other tests of cognitive performance or on psychomotor function. However, long‐term lithium treatment (mean duration of use approximately four years) was associated with a ‘moderate’ impairment of psychomotor performance. The authors note that their findings appear to contradict evidence than lithium may have neuroprotective properties. Copyright © 2009 Wiley Interface Ltd