A new neuroimaging study provides evidence that the neural mechanisms underlying social cognition are altered among those with a familial history of major depressive disorder. The findings have been published in the journal Depression & Anxiety.
“I am interested in the study of theory of mind, that is the ability to infer the hidden mental states, such as feelings, preferences or goals of other people, and was curious about whether people suffering from depression have a change in their theory of mind cognition, which has mixed results in the research thus far,” said study author Lindsey Tepfer, a PhD student at Dartmouth College.
“Some studies have found evidence for altered theory of mind among individuals with depression, while others have not. Moreover, given the high heritability of depression, I wanted to explore whether people with a family history of depression might show symptoms of altered theory of mind as well, perhaps serving as an early sign that they will ultimately experience a depressive episode.”
For their study, the researchers examined data collected from 279 participants from the Human Connectome Project. The sample included 71 individuals with a lifetime history of clinical depression, 103 with a family history of clinical depression, and 105 controls. The participants completed seven neurocognitive tests as researchers used functional magnetic resonance imaging (fMRI) to record their brain activity. Of primary interest to Tepfer and her co-authors, one of the tests was a social cognition task, which assessed theory of mind processing.
There was no significant difference in brain connectivity between those with a lifetime history of depression and those with a family history of depression. But there was a difference observed between those with a family history of depression and the control group.
The researchers found that individuals with a familial risk of depression, compared to the control group, tended to have increased functional connectivity between the ventromedial prefrontal cortex and the nucleus accumbens, left dorsolateral prefrontal cortex, and subregions of the cerebellum during the social cognition task. These brain regions have been shown to play a key role in processing social information and rewarding stimuli.
“Our study shows that healthy individuals who have a parent with a history of depression process social interactions in a way that is distinct from healthy individuals with no family history of depression,” said co-author David V. Smith, an assistant professor of psychology at Temple University and the head of the Neuroeconomics Laboratory.
“This observation is important because it shows that merely having a parent with a history of depression could lead to changes in how our brains process social information and may contribute to risk for developing depression.”
But the cross-sectional nature of the data prevents the researchers from making any strong conclusions about causality. Longitudinal research is needed to better understand how these neural alterations influence the development of depressive symptoms.
“One major caveat with our findings is that they reflect a snapshot in time. We don’t know how these patterns of brain connectivity evolve over time as someone develops depression, so we can’t be sure if the brain regions identified in our study could be targeted in interventions,” Smith explained.
“On a more general note, I should point out that we don’t know much about the exact role family history plays in our results. Is it genetic? Is it something about how these individuals were raised? These are important questions to examine in future work.”
Funded by the U.S. National Institutes of Health, the Human Connectome Project uses high-quality brain scans to measure cortical architecture, activity, connectivity, and topography. The project also collects a variety of behavioral data from participants.
“This study would not have been possible without the Human Connectome Project making all of their data freely available to the general public,” Smith said. “It’s great to see more and more researchers in neuroscience follow this example and share their own data.”
The study, “Family History of Depression is Associated with Alterations in Task-Dependent Connectivity between the Cerebellum and Ventromedial Prefrontal Cortex“, was authored by Lindsey J. Tepfer, Lauren B. Alloy, and David V. Smith.