Factors associated with onset-age in major affective disorders

Abstract

Background: Research findings on factors associated with onset-age (OA) with bipolar (BD) and major depressive disorders (MDD) have been inconsistent, but often indicate greater morbidity following early OA.

Methods: We considered factors associated with OA in 1033 carefully evaluated, systematically followed mood disorder subjects with DSM-5 BD (n = 505) or MDD (n = 528), comparing rates of descriptive and clinical characteristics following early (age <18), intermediate (18-40), or later onset (≥40 years), as well as regressing selected measures versus OA. Exposure time (years ill) was matched among these subgroups.

Results: As hypothesized, many features were associated with early OA: familial psychiatric illness, including BD, greater maternal age, early sexual abuse, nondepressive first episodes, co-occurring ADHD, suicide attempts and violent suicidal behavior, abuse of alcohol or drugs, smoking, and unemployment. Other features increased consistently with later OA: %-time-depressed (in BD and MDD, women and men), as well as depressions/year and intake ratings of depression, educational levels, co-occurring medical disorders, rates of marriage and number of children.

Conclusions: OA averaged 7.5 years earlier in BD versus MDD (30.7 vs. 38.2). Some OA-associated measures may reflect maturation. Associations with family history and suicidal risk with earlier OA were expected; increases of time-depressed in both BD and MDD with later OA were not. We conclude that associations of OA with later morbidity are complex and not unidirectional but may be clinically useful.

Keywords: age at onset; bipolar disorder; major depression; morbidity.

FIGURE 1

(A) Percentage of time at risk in depression versus age at onset of major affective disorders in 1033 subjects with matched exposure times (years at risk). Slope = 0.302 [95% CI: 0.215–0.390], t‐score = 6.77, p < 0.0001. (B) Percentage of time at risk in mania or hypomania versus onset age. Slope [95% CI] = −0.0009 [−0.0014 to −0.0005], t = 3.91, p = 0.0001. Note that there was more depression and less [hypo]mania with older illness onset.