Multidimensional Analysis of Major Depression: Association Between BDNF Methylation, Psychosocial and Cognitive Domains

Evolution of Depressive Symptoms Among Depression Subtypes of Clinical and Functional Variables in Primary Care in Chile

OBJECTIVE

To compare the evolution of depressive symptoms among depressive subtypes based on clinical and functional variables in a sample of primary care in Chile.

METHODS

A longitudinal study was conducted in the Maule Region of Chile, focusing on 8 primary care from February 2014 to September 2015. Clinical and functional variables, including Mini International Neuro-psychiatric Interview, Outcome Questionnaire interpersonal and social sub-scales, were applied in a latent class analysis. This analysis categorized 210 patients into 3 subtypes: complex depression (N = 100), recurrent depression (n = 96), and unique depression (n = 14). Complex depression, exhibited a higher probability of suicide attempts, interpersonal and social dysfunction, and association with adverse childhood experiences according the Brief Physical and Sexual Abuse Questionnaire. Patients were monitored over 1 year with the Hamilton scale. The Kruskal-Wallis, non-parametric test, followed by paired Mann-Whitney test evaluated difference in the severity of depressive symptoms between the groups. Additionally, data on mental health interventions were collected.

RESULTS

Out of the 210 patients, 89% were women, with a median age of 50 (range 37-58), and 40.1% with only primary education. Sociodemographic characteristics not differ between groups. Significant differences in depressive symptom severity between the groups were found (X2 90.06, P < .001, Kruskal-Wallis test, η2 = 0.084). Post hoc analyses indicated higher depressive symptoms in complex depression compared to recurrent (Z = -9.501, P < .001) and unique (Z = -2.877, P = .004) depression, with no significant difference between recurrent and unique depression (Z = -1.58, P = .113). There were no differences in the number of medical and psychological controls between the groups. The patients with complex depression required greater modifications in the pharmacological prescriptions than those belonging to the other groups.

CONCLUSION

These results provide additional evidence of a complex depression subtype in primary care in Chile associated with adverse childhood experiences, that had worse resolution of depressive symptoms. Contrary to expectations, patients belonging to this group did not receive further medical and psychological interventions, probably due to a lack of specific clinical recommendations.

Childhood adverse events and BDNF promoter methylation in later-life

Studies have shown that the effects of early-life stress and trauma can be enduring, with long-term negative effects on health. Epigenetics, including DNA methylation, have been implicated as a potential mechanism for these effects. Brain-derived neurotropic factor (BDNF) is a neurotransmitter involved in learning and memory, and altered BDNF promoter methylation measured in peripheral tissue has been found with early-life stress. However, whether such methylation differences remain stable into later life, is unknown. This study aimed to investigate the association between childhood adversity and BDNF promoter methylation in adults aged 65 years and over. Data came from a large study of older community-dwelling individuals in France (ESPRIT). Information on three major childhood adverse events, namely abuse/maltreatment, war/natural disaster, and financial difficulties/poverty, was obtained by retrospective reporting from participants of ESPRIT study. BDNF promoter I and IV methylation was assessed in blood and buccal tissue. Linear regression analysis was performed, adjusting for age, sex, education, depression, and morbidity. Among 927 participants, there was no strong evidence that childhood abuse/maltreatment or financial difficulties/poverty were associated with BDNF methylation in older individuals. For war/natural disaster, differential methylation at four of twenty-nine CpG sites was observed, however, these would not have remained significant after correction for multiple testing. Together, these findings do not support a long-term association between adverse childhood events and BDNF methylation in older age, but further large prospective studies are needed, which do not target specific genes, but consider DNA methylation across the genome.