Lithium is used as a first line treatment in bipolar disorder. The 
neuroprotective effects of lithium in this indication tend to be well known and 
are mediated by its action on two enzymes: glycogen synthase kinase-3 and 
inositol monophosphatase-1. Preclinical and clinical studies seek to evaluate 
the neuroprotective effect of lithium in neurodegenerative disorders. The aims 
of this literature review is to gather clinical studies that investigated the 
efficacy of lithium in neurodegenerative diseases, using a systematic method 
based on PubMed data. Results were found concerning Alzheimer's disease and 
related dementias, Huntington's disease, amyotrophic lateral sclerosis and 
spino-cerebellar ataxia. Lithium exposure showed a potential neuroprotective 
effect in studies on psychiatric populations with a lower prevalence of 
Alzheimer's disease in exposed patients. In patients with mild cognitive 
impairment, lithium would be associated with clinical improvement and a lower 
level of cerebrospinal phosphorylated tau protein. Lithium would allow at least 
a partial improvement in symptoms, including suicidal thoughts, in Huntington's 
disease. Despite several positive case reports and short studies, further 
controlled researches have failed to substantiate any positive effects of 
lithium exposure in amyotrophic lateral sclerosis. In spinocerebellar ataxia, 
introduction of lithium may be of benefits in terms of improvement of cerebellar 
symptoms. Large randomized controlled trials are required to asses the effect of 
early exposure lithium in these indications, based on reliable biological 
markers of disease.