A longitudinal study conducted in Germany revealed that negative life events experienced during childhood can predict depressive symptoms later in life. This development of depressive symptoms was preceded by the accelerated thinning of the orbitofrontal cortex region of the brain. The research was published in JCPP Advances.
Negative life events are unpleasantly perceived events that may exceed an individual’s ability to cope. These can include accidents, illnesses, and deaths, issues with family, friends, sexuality, or challenges in social and academic environments. Negative life events in childhood also include abuse, neglect, parental divorce, or the loss of a loved one. These events may adversely affect a child’s social and cognitive development, leading to difficulties in forming healthy relationships and achieving academic success.
Studies have proposed that severe forms of negative life events might be associated with alterations to the volume of the orbitofrontal cortex region of the brain. The orbitofrontal cortex is a brain region involved in decision-making, emotional regulation, and the processing of rewards and punishments. It helps individuals make choices and evaluate the potential consequences of their actions. Studies have indicated that thickness of this brain region might be reduced in adolescents exposed to childhood adversity compared to adolescents without such experiences.
Study author Lea L. Backhausen and her colleagues wanted to better explore the findings about the reduced thickness of the orbitofrontal cortex region in a longitudinal study. They decided to follow a group of adolescents starting at the age of 14 and observe, using magnetic resonance imaging, whether adolescents who experienced severe negative life events in childhood indeed undergo accelerated thinning of this region of the brain. They were also interested in the links between this process and the development of depression.
The study included 534 adolescents participating in a larger longitudinal project known as IMAGEN, with 175 of them being girls. The researchers conducted assessments at four points, beginning when the participants were 14 years old, with the final assessment occurring when they were, on average, 22 years old.
During the first assessment, participants completed a measure of negative life events (the Life Events Questionnaire) covering 39 life events that typically occur during childhood and adolescence. At the fourth (the last) assessment, participants completed a measure of depression (the Center for Epidemiologic Studies Depression Scale). At each of the four assessments, participants also underwent magnetic resonance imaging of their brains.
Results showed that 99% of participants reported at least one early negative life event. The median number of reported events was 6. By the fourth assessment, 76% of the participants reported experiencing subclinical depressive symptoms. Overall, as participants got older, their orbitofrontal cortex areas became gradually thinner. However, the trend of this changes showed substantial variation between individuals.
Further analysis showed that individuals reporting a higher number of early negative life events tended to exhibit more depressive symptoms at the study’s conclusion. However, the number of negative life events did not correlate with the orbitofrontal cortex’s thickness at the study’s outset. The study found no association between the changes in thickness of this area and the negative life events.
However, participants who had thicker orbitofrontal cortices at the beginning and experienced accelerated thinning over the course of the study reported more depressive symptoms at the end. Additionally, males had thicker orbitofrontal cortices at the beginning of the study than females, but no gender differences were observed in the rate of thinning.
“Taken together, current findings extend previous studies by showing that early NLE [negative life events] can predict depressive symptoms in the long term. Moreover, using a complete longitudinal design with four waves, results indicate that accelerated OFC [orbitofrontal cortex] thinning may precede depressive symptoms giving new insight into the neurodevelopmental factors associated with the development of depression,” the study authors concluded.
The study sheds light on the neural and psychological mechanisms underpinning the development of depression. However, it also has limitations that need to be taken into account. Notably, the participants generally reported low levels of negative life events at the study’s start, which might have influenced the observed lack of effect on orbitofrontal cortex thinning. Additionally, the study treated negative life events as a singular score without considering the timing, frequency, duration, or other details of these events. Consequently, studies on children who have experienced more intensive early negative life events might not produce identical results.
The paper, “Interplay of early negative life events, development of orbitofrontal cortical thickness and depression in young adulthood,” was authored by Lea L. Backhausen, Jonas Granzow, Juliane H. Fröhner, Eric Artiges, Marie‐Laure Paillère‐Martinot, Hervé Lemaître, Fabio Sticca, Tobias Banaschewski, Sylvane Desrivières, Antoine Grigis, Andreas Heinz, Rüdiger Brühl, Dimitri Papadopoulos‐Orfanos, Luise Poustka, Sarah Hohmann, Lauren Robinson, Henrik Walter, Jeanne Winterer, Gunter Schumann, Jean‐Luc Martinot, Michael N. Smolka, and Nora C. Vetter.