A survey of patients' knowledge about lithium therapy in the elderly

Lithium is commonly used in the treatment of various psychiatric disorders. It has a narrow therapeutic range and a mortality rate of 9% in patients intoxicated during maintenance therapy. Therefore, for lithium to be prescribed safely, clinicians must ensure that patients are aware of features of lithium toxicity. We aim to identify patients' knowledge of lithium in the elderly population and associated factors that may influence this knowledge.

The Lithium Knowledge Test (LKT) is a brief questionnaire that was developed as a means of identifying patients' practical and pharmacologic knowledge, which is important if therapy is to be safe and effective. The survey was conducted in the outpatient service of the Department of Old Age Psychiatry attached to a university teaching hospital in an urban area in Ireland between January 2011 and July 2011. A total of 33 patients participated in the survey, and the LKT questionnaires were completed by all participants. The LKT scores are obtained by adding up the responses to the questions, while the LKT hazard scores are obtained by adding together the responses to the questions on symptoms of toxicity. The result was analyzed using SPSS version 20 (SPSS Inc, Chicago, Illinois), and the relationships between LKT scores and LKT hazard scores as well as other variables were examined using Pearson's correlation coefficient.

The mean LKT score of our sample population was 4.45, suggestive of poor knowledge of lithium, and the mean LKT hazard score was 5.85, highly suggestive of potentially hazardous lack of knowledge. There was a significant negative correlation between the LKT score and hazard score (r = -0.65, P < .01 [1-tailed]).

The survey results highlight the need for patients to be given comprehensive information about lithium prior to commencement of treatment and a refresher educational program during lithium therapy.