OUTCOME OF LITHIUM PROPHYLAXIS - A PROSPECTIVE FOLLOW-UP OF AFFECTIVE-DISORDER PATIENTS ASSIGNED TO HIGH AND LOW SERUM LITHIUM LEVELS

The purpose of the study was to examine the outcome of long-term lithi um treatment in consecutively admitted affective disorder patients ass igned to high and low serum lithium levels. A total of 91 patients wer e diagnosed according to DSM-LII criteria and randomly allocated to tw o open treatment groups in which prophylactic lithium was administered in high serum lithium 0.8-1.0 mmol L-1) and low (serum lithium (0.5-0 .8 mmol L-1) doses, respectively. The patients were followed for 2 yea rs or until discontinuation of lithium treatment or readmission to hos pital for recurrence of affective illness. The main outcome of the tre atment groups was compared with Kaplan-Meier survival curves and by Co x regression analysis. A total of 31 patients (34%) completed 24 month s of prophylactic lithium treatment without recurrence and readmission to hospital. In total, 18 patients (20%) suffered a recurrence on lit hium, and 42 patients (46%) discontinued lithium or were lost to follo w-up. No effect of treatment group was seen, either for the total pati ent group or for the large subgroup of bipolar patients when analysed separately. A number of patients did not maintain their original assig nment to the high serum lithium levels group. The results were analyse d both according to assignment and according to actual serum lithium l evels. Abuse of alcohol or medication was associated with a poor outco me. Only one third of the patients completed 2 years of lithium prophy laxis successfully. No difference in the protection against recurrence s was observed between patients maintained on high and low serum lithi um levels.