Lithium, a Therapy for AD: Current Evidence from Clinical Trials of Neurodegenerative Disorders

Background: Preclinical studies have shown that lithium modifies pathological cascades implicated in certain neurodegenerative disorders, such as Alzheimer's disease (AD), Huntigton's disease (HD), multiple system atrophy (MSA) and amyotrophic lateral sclerosis (ALS). A critical question is whether these pharmacodynamic properties of lithium translate into neurodegenerative diseases modifying effects in human subjects. Methods: We reviewed all English controlled clinical trials published in PubMed, PsycINFO, Embase, SCOPUS, ISI-Web with the use of lithium for the treatment of neurodegenerative disorders between July 2004 and July 2014. Results: Lithium showed evidence for positive effects on cognitive functions and biomarkers in amnestic mild cognitive impairment (aMCI, 1 study) and AD (2 studies), even with doses lower than those used for mood stabilisation. Studies of Li in HD, MSA and CSI did not show benefits of lithium. However, due to methodological limitations and small sample size, these studies may be inconclusive. Studies in ALS showed consistently negative results and presented evidence against the use of lithium for the treatment of this disease. Conclusion: In absence of disease modifying treatments for any neurodegenerative disorders, the fact that at least 3 studies supported the effect of lithium in aMCI/AD is noteworthy. Future studies should focus on defining the dose range necessary for neuroprotective effects to occur.