Neuroticism in Remitted Major Depression: Elevated with Early Onset but Not Late Onset of Depression

Factors related to age at depression onset: the role of SLC6A4 methylation, sex, exposure to stressful life events and personality in a sample of inpatients suffering from major depression

BACKGROUND

An early onset of depression is associated with higher chronicity and disability, more stressful life events (SLEs), higher negative emotionality as described by the primary emotion SADNESS and more severe depressive symptomatology compared to depression onset later in life. Additionally, methylation of the serotonin transporter gene (SLC6A4) is associated with SLEs and depressive symptoms.

METHODS

We investigated the relation of SLEs, SLC6A4 methylation in peripheral blood, the primary emotions SADNESS and SEEKING (measured by the Affective Neuroscience Personality Scales) as well as depressive symptom severity to age at depression onset in a sample of N = 146 inpatients suffering from major depression.

RESULTS

Depressed women showed higher SADNESS (t (91.05) = - 3.17, p = 0.028, d = - 0.57) and higher SLC6A4 methylation (t (88.79) = - 2.95, p = 0.02, d = - 0.55) compared to men. There were associations between SLEs, primary emotions and depression severity, which partly differed between women and men. The Akaike information criterion (AIC) indicated the selection of a model including sex, SLEs, SEEKING and SADNESS for the prediction of age at depression onset. SLC6A4 methylation was not related to depression severity, age at depression onset or SLEs in the entire group, but positively related to depression severity in women.

CONCLUSIONS

Taken together, we provide further evidence that age at depression onset is associated with SLEs, personality and depression severity. However, we found no associations between age at onset and SLC6A4 methylation. The joint investigation of variables originating in biology, psychology and psychiatry could make an important contribution to understanding the development of depressive disorders by elucidating potential subtypes of depression.

Personality Disturbances in Melancholic and Nonmelancholic Unipolar Major Depression: A Systematic Review and Meta-Analysis

Although melancholic depression has been associated with a more adequate premorbid personality style, the empirical evidence supporting this statement is inconclusive. We conducted a systematic review and meta-analyzed studies comparing the presence of personality disturbances in melancholic and nonmelancholic subtypes of major depressive disorder (MDD). We defined a) a continuous outcome, defining personality traits as a dimensional construct, and b) a dichotomous outcome, defined as the presence/absence of personality disorders (PD). We also evaluated the role of potential moderators. Our results showed significantly higher levels of neuroticism and interpersonal sensitivity, and a higher likelihood of presenting a PD in nonmelancholic depression. No significant differences were found for extraversion. The scarcity of studies and high heterogeneity were among our limitations. In conclusion, personality disturbances seem to be overrepresented in nonmelancholic MDD. The assessment of personality disturbances can be useful in clinical practice and in the study of MDD heterogeneity.