Age at onset (AAO) of depression is associated with greater symptom severity of depressive disorders, and associations between symptoms differ depending on AAO of depression, according to a recently published article in the Journal of Affective Disorders.

Researchers utilized data gathered from 3184 depressed participants who were treated in an outpatient setting (Sequenced Treatment Alternatives to Relieve Depression Study [STAR*D]; ClinicalTrials.gov Identifier: NCT00021528). All participants began s-citalopram and were randomly assigned to a medication adjustment or psychotherapy when they did not achieve remission. The participants were assessed for 11 symptoms related to depression, and their symptom levels were recorded on a 5-point scale.

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Before beginning treatment, participants retrospectively reported depression. Participants were aged 18 to 75 years. Depending on depression AAO, the participants were divided into 4 groups: child, adolescent, young adult, or middle age. Researchers used multiple regression to determine the strength of relationships between symptoms and depression AAO. They used network analysis to determine the network of associations among symptoms for each age group and to statistically test for differences among age groups in their network structures.

Earlier depression AAO was significantly associated with greater energy loss (P =.03), depressed mood (P =.002), hypochondriasis (P =.02), guilt (P <.0001), suicidality (P <.0001), anhedonia (P =.007), and anxiety (P <.0001). Symptoms related to sleep were the only factors that significantly decreased in severity with decreasing depression AAO. The network analysis revealed that the adolescent AAO symptom network significantly differed in strength and structure from the middle age network (P =.002 and P =.001, respectively). The differences in strength and structure of the networks between adolescent AAO and young adult AAO were marginally significant (P =.07 and P =.08, respectively). The child AAO network differed from the middle age AAO network in strength (P =.047), but not in structure. The child AAO network did not differ in strength or structure from the adolescent or young adult AAO.

The researchers listed 3 study limitations. First, AAO was recalled retrospectively and thus is subject to erroneous reporting. Second, the cut-offs for the AAO networks were arbitrary. Third, unexamined variables may explain more of the variation in relationships between symptoms and depression AAO.

The researchers of the study concluded that “onset of depression earlier in life, and particularly during adolescence leaves a specific scar that affects the severity, structure, and presentation of depression in adulthood.” This is important because “[t]hese results may inform research identifying the pathophysiology of depression, and demonstrate that age at onset may be an important factor in fully describing current episodes of depression in patients and in future research.”

Reference                                                            

Baez LM, Heller AS. Impact of age at onset on the phenomenology of depression in treatment-seeking adults in the STAR*D trial [published online October 26, 2019]. Journal of Affective Disorders. doi: 10.1016/j.jad.2019.10.036