The profile and severity of lithium-induced side effects in mentally healthy subjects.

In a double-blind, placebo-controlled, crossover design various side effects (= unwanted effects) during 6 months of therapeutic serum lithium levels (0.7-1.1 mmol/1) to nonpsychiatric patients were studied. The side effects were measured by self-rating scales and independent observer rating scales administered every 2-4 weeks throughout the study. After months of treatment, lithium induced hand tremor and thirst/polyuria; however, without any relationship to the serum levels of lithium. The frequency of tremor was highest in patients above the age of 60 years. No initial sedative-like lithium effect was found.