[Lithium in the prophylaxis of recurrent affective disorders. Effectiveness of low plasma levels and predictors to clinical response (author's transl)].

Thirty-eight patients suffering from recurrent affective disorder were treated at the Lithium Clinic of the Department of Clinical Psychiatry, University of Florence, with lithium carbonate for a period of 3-8 years; twenty-four (76%) had good response. The latter was defined as a decrease of at least 50% of recurrences during the period of treatment when compared with those of the period preceding treatment. This improvement was obtained in spite of the fact that plasmatic lithium was maintained within 0.40-0.80 mEq/l, a range lower than recommended. However, patients who sometimes let this value fall below 0.40 had significantly increased relapses. No marked toxic effect was recorded. Some factors (bipolar illness, typical symptom pattern and, probably, family history of affective disorder) were associated with a favourable outcome. However, the absence of these did not predict a poor response in more than 40% of the cases. The authors therefore conclude that it is worthwhile to start a lithium treatment whenever a diagnosis of recurrent affective disorder is met.