Adolescents Have a More Delayed Progression From MDD to BD, Relative to Adults

Children and adolescents with major depressive disorder (MDD) may experience a more delayed progression of bipolar disorder (BD) compared with adults, according to new research published in JAMA Psychiatry.

While the onset of BD typically occurs between 12 and 25 years of age, the diagnosis and treatment of BD is commonly delayed and extended periods of untreated BD are associated with adverse health consequences. The progression of bipolar disorder from MDD is a growing area of research and little is known about the timing of the transition. The objective of the current study was to determine the association between age at MDD onset and progression to BD.

Investigators conducted a population-level study using data from the Stockholm MDD Cohort (SMC) to identify all individuals diagnosed with MDD in Stockholm, Sweden, between January 1, 2010, and December 31, 2018. Patients who experienced their first MDD episode between January 1, 2010, and December 31, 2013 and were younger than 41 years during the defined study period were included in the analysis. The investigators followed this cohort from MDD onset to either BD diagnosis or study end in 2018. Propensity score matching was used to balance covariates and patients were stratified into early (within 3 years of MDD onset) or late (3 or more years after MDD onset) BD converters.

Across the study period, the investigators identified 37,086 first MDD episodes. In the balanced study sample, 114 children and adolescents (0 to 17 years of age) and 114 adults (18 to 40 years of age) were included for analysis. The children and adolescent cohort had a mean (SD) age of 15.3 (1.6) years, 81.6% were girls, and 7.0% experienced an early transition to BD. The adult cohort had a mean (SD) age of 24.5 (6.3) years, 84.2% were women, and 17.5% had an early transition to BD.

The investigators found that children and adolescents were significantly less likely to have an early conversion to BD (odds ratio [OR], 0.42; 95% CI, 0.20-0.88; P =.02), relative to adults. However, children and adolescents had higher psychiatric outpatient visit rates following their MDD diagnosis (mean [SD] visits per month, 1.21 [1.07]) compared with adults (0.97 [0.98]; P =.01).

Following BD diagnosis, the investigators did not observe any significant differences in inpatient care duration between early and late converters. However, children and adolescents had a substantial decrease in mean antidepressant prescriptions after BD diagnosis – decreasing from 18 prescriptions to 7 (OR, 0.08; 95% CI, 0.002-0.56; P =.003). Similarly, the mean number of antidepressant prescriptions among adults decreased from 26 to 11 after BD diagnosis (OR, 0.06; 95% CI, 0.001-0.40; P <.001).

These findings indicate that a younger age of MDD onset may be associated with a slower transition to BD. The investigators concluded, “These findings suggest that adolescents may experience delayed BD progression and that diagnosis is associated with a substantial reduction in inpatient care in all age groups, coinciding with a decreased use of antidepressants.”

Study limitations include the small sample sizes and the inability to determine if the transition from pediatric to adult psychiatric services affected the timing of BD diagnoses.

Disclosure: This research was supported by Region Stockholm. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

This article originally appeared on Psychiatry Advisor