The aim of the study is to provide information about lithium effectiveness and safety in the treatment of very old patients with mood disorders.

All patients aged ≥75 years attending our private practice in the past 10 years.

We treated 183 subjects aged ≥75 years. 25 were in the lithium group and 138 in the no-lithium group. Bipolar disorder diagnosis and history of previous suicide attempts were more frequent in the Li group. Mean duration of lithium treatment was 31.3 ± 35.0 months. Mean daily dose of lithium was 390 (± 178.5) mg. Treatment with lithium was associated with better Clinical General Impression-Improvement scores than other psychopharmacological treatments. Rates of discontinuation were not significantly different between lithium and other treatments. In no patient, hypothyroidism or renal failure were major clinical problems.T4 treatment (a proxy for hypothyroidism) was prescribed to 8 (32%) of lithium-treated patients. Lithium was withdrawn in 6 (24%) patients.

The reasons for the suspension of lithium were:

1. 1) Unproven effectiveness of the drug for the individual patient.

2. 2) Occurrence of serious cardiac or renal disease, independent of the use of lithium.

3. 3) Erratic and unpredictable metabolism of lithium in the very elderly.

4. 4) Poor compliance (two cases).

5. 5) Age related spontaneous mitigation of the disease.

Lithium can be valuable in the treatment of elderly patients, with adequate precautions. Elderly patients require lithium dosages that are 25 to 50% lower than those used in younger individuals. A single bedtime dosing regimen is recommended.