SAN DIEGO – More than two-thirds of children and adolescents with major depressive disorder who were treated with fluoxetine were in remission by week 12 of treatment, yet almost half of remitters had at least one residual symptom by week 12.
The findings are important because “knowing how early clinicians may expect response or remission in their patients is clinically valuable,” Dr. Rongrong Tao said at the annual meeting of the American Academy of Child and Adolescent Psychiatry.
“It may improve [drug] adherence. Knowing the time course of depressive symptom improvement may be helpful in guiding” treatment decisions, Dr. Tao said.
In an open-label study funded by the National Institute of Mental Health, Dr. Tao and her associates in the department of psychiatry at the University of Texas Southwestern Medical Center at Dallas enrolled 168 outpatients aged 7–18 years who had a diagnosis of nonpsychotic major depressive disorder.
Patients with a diagnosis of bipolar I or II disorder were excluded from the study, as were those with anorexia nervosa or bulimia and those with a history of alcohol or substance abuse dependence within 6 months of study entry.
Between 1999 and 2005, the patients received 12 weeks of fluoxetine, starting with a dosage of 10 mg/day for week 1 and increased to 20 mg/day for week 2. Nonresponders received a dosage of 40 mg/day at week 6. The average age of the 168 patients was 12 years, 30% had a recurrent major depressive disorder, and their mean Children's Depression Rating Scale-Revised (CDRS-R) score was 57.57. In addition, 40% had attention-deficit hyperactivity disorder, 32% had dysthymia, and 14% had generalized anxiety disorder.
Study visits occurred weekly for the first 4 weeks and biweekly for the remaining 2 months. During study visits, the researchers administered a battery of tests to assess clinical response, including the Kiddie Schedule for Affective Disorders and Schizophrenia-Present and Lifetime version (K-SADS-PL), the CDRS-R, and the Clinical Global Impression scale.
Dr. Tao reported that the rates of remission were 35% by week 4, 48% by week 6, and 66% by week 12. However, 47% of remitters had at least one residual symptom by the end of 12 weeks, most commonly impaired school performance (19%), impaired sleep (12%), irritability (11%), and low self-esteem (9%).
Clinical response also improved in a stepwise fashion, to rates of 68% by week 4, 76% by week 6, and 81% by week 12. Children aged 11 and younger had earlier responses than their older counterparts did, but by week 12, “their response rates were almost identical,” she said.