By Michele Morningstar, Ph.D.
Developing depression during adolescence, compared to later in life, is often associated with more negative outcomes as an adult. Researchers think this is the case because depression can impact the way we navigate social situations, and impair our social learning—that is, how to interpret others’ intent, how to behave in social groups, how to form strong friendships, etc. To understand this possibility more, the current study set out to test whether there was evidence of different “social learning” in girls with and without depression, as they interacted with peers during a chatroom-style situation.
How can you measure “social learning”?
One way we can measure the extent to which someone is adapting to a situation is by looking at their brain’s response. Many areas of the brain have an interesting property: if you present the same stimulus over and over again, neural response in some areas will start to go down over time. For example, your amygdala (a part of the brain that tends to activate in response to things that are salient, or important, in the environment) will initially respond to a given stimulus X. But, the more you see X, the less your amygdala will respond to it. This is called “habituation”. We can use the phenomenon of habituation to see how the brain adapts to repeated social scenarios, like social rejection or acceptance, to infer how it has learned to respond.
What did the study do?
First, we recruited teenage girls (ages 10 to 17 years old) who either had:
a current diagnosis of depression
a parent with a history of depression, but no current diagnosis themselves
no person experience of depression, and no parental history of depression
We did this so that we could see whether the experience of depression, or just the risk of developing depression (which is higher in people whose parents have been diagnosed), would impact how the brain responded to tricky social situations.
We scanned participants’ brains (using functional magnetic resonance imaging, or fMRI) while they joined an online “chatroom” with two other teens. The teens were told that they would take turns selecting who they wanted to talk to about specific topics. The participant went first, and then each of the other two people went next. The trick is that neither of those two other people were real: they were programmed to either repeatedly choose the participant (be “nice”) or repeatedly reject the participant (be “mean”). We looked at how participants’ amygdala responded to both repeated acceptance and repeated rejection from either person.
What did we find?
Non-depressed girls, including both those with and without parental histories of depression, showed reductions in amygdala response to repeated rejection from peers over time. Even though amygdala activation started off high—being rejected is a salient event that your amygdala will tend to respond to!—, it habituated after multiple rejections. This was NOT the case for girls with depression: instead of habituating, their amygdala response stayed high for each and every instance of rejection.
Of course, the amygdala also habituated to repeated acceptance. But, there was no difference in how girls with and without depression responded to being chosen by the “nice” peer.
What does this mean?
Teenage girls experiencing depression are not “updating” their neural response to being rejected in the same way as girls without depression are. Instead of “getting used to it”, their amygdala continues to respond to the salient social threat—even after being repeatedly rejected by the “mean” peer. This kind of pattern suggests alterations in social learning in teen girls with depression.
Results like these help us understand what might be going on “under the hood” in teens with depression, and why this may be such a chronic condition. It is possible that the changes in social learning we see at the neural level contribute to difficulties in social relationships. We would need to follow these participants over time in longitudinal studies to be able to say whether that is the case, but the current findings point to potential mechanisms through which adolescent depression could impact social functioning.
To learn more, READ THE FULL PUBLICATION:
Morningstar, M., Gravelle, M.N.K., Dickstein, D.P., Silk, J.S., Dahl, R.E., Nelson, E.E., Yee, D., & Stroud, L.R. (2026). Reduced amygdala habituation to anticipated social rejection in youth with major depressive disorder. Journal of Affective Disorders, 403, 121380. doi: 10.1016/j.jad.2026.121380