Exposure to Stress and Separation-induced BDNF impairments in adolescents.

Background: Although the deleterious effects of separation during early childhood have been extensively studied, little is known regarding other stress-sensitive periods in development, such as adolescence. Also unknown are the biological mechanisms explaining its deleterious effects. This study was carried out to determine how different types of separation can impact neurotrophic factors during adolescence.

Methods: A community sample of 450 Hispanic adolescents was queried in 3 separate visits about regarding four indicators of stress exposure: migration, low closeness to parents, divorce, and growing up with individuals other than their biological parents. Chronological age at the time of exposure to the stressor were documented. BDNF and Pro-BDNF levels were obtained at three time points during the length of the study.

Results: The expression of pro-BDNF and m-BDNF was altered by separation, both divorce and death. Of concern, near half of the sample reported their parents to be divorce as a result the majority had mothers that work full time. Exposure to recent life events such as a parent divorce resulted in a time-point dependent, differential down-regulation of m-BDNF levels. Parent-child conflict positively related to BDNF. Specifically, BDNF was affected only in those the father/male adolescent relationship.

Conclusion: Our data confirmed that separation triggers alterations in BDNF, even after the growth spurt of the brain during early childhood. The important implication of this study is the persistent abnormal levels of BDNF. The prolonged alteration is of concern when considering that BDNF plays a critical role in the pruning process occurring during adolescence. Additional studies are needed to assess whether these alterations can lead to neuropsychological disruptions.