Cortisol changes in long-term lithium therapy

a.m. and p.m. serum cortisol levels were investigated in a group of 53 patients before the start of long-term lithium therapy (I) and again after 4 months (II) and 12 months (III) on lithium. The patients were assessed by means of the CPRS and scores for 28 depression items were calculated. When 5 patients with manic/hypomanic scores were excluded the remainder (n = 48) showed a significant decrease in a.m. serum cortisol levels after 1 year on lithium. Those patients with the greatest differences between the CPRS scores before lithium and after 12 months on lithium also displayed significant differences between a.m. and p.m. cortisol levels before the start of lithium and after 12 months of lithium therapy.