Slightly More Complicated For Anxiety and Depression
Ferrari, F., & Villa, R. F. (2017). The Neurobiology of Depression: an Integrated Overview from Biological Theories to Clinical Evidence.
Molecular neurobiology, 54(7), 4847–4865.
https://doi.org/10.1007/s12035-016-0032-y
Ionescu, D. F., Niciu, M. J., Mathews, D. C., Richards, E. M., & Zarate, C. A., Jr (2013). Neurobiology of anxious depression: a review.
Depression and anxiety, 30(4), 374–385.
https://doi.org/10.1002/da.22095
Shimko, G. A., & James, K. H. (2025). The Relationship Between Motor Development and ADHD: A Critical Review and Future Directions.
Behavioral sciences (Basel, Switzerland), 15(5), 576.
Introduction
In the past two entries, the neurodivergent conditions mentioned focused largely on a single portion of the brain. However, for anxiety and depression, multiple portions of the brain are affected. In retrospect, it makes sense because anxiety and depression do not occur together, but rather they occur subsequently! In summary, anxiety will ultimately cause a feedback loop which leaves the individual feeling trapped, tired, and helpless. Constant exposure to this loop will eventually lead to the individual experiencing increasingly continuous bouts of depression.
The three portions of the brain which are related to anxiety and depression are the hippocampus, prefrontal cortex, and amygdala. For a brief recap of the situation, the hippocampus is responsible for learning, memory retention, and spatial navigation. The prefrontal cortex, as mentioned in the ADHD blog post, is involved with emotional regulation, and finally, the amygdala processes emotions that are seen in the fight-or-flight responses; such emotions include fear, anger, aggression, and anxiety. Just by looking at these three components of the brain, it can be seen why they are affected in individuals with anxiety and depression.
.png)
Ferrari and Villa, 2017
In terms of activation potential, when experiencing a depressive episode, anxious depressive individuals’ amygdala was found to not activate property, which leads credence to why the anxiety and depression might run rampant. Essentially, a lack of neurobiological control leads to negative emotions overwhelming the patient (Ionescu et al., 2013). Additionally, for both the hippocampus and amygdala, the volume was smaller in the ground which suffered from anxiety and depression.
One aspect of neurobiology that I have noticed as I was studying the relationship between the brain morphology and volume and neurodivergent symptoms, is that it is hard to simply say a specific portion of the brain is responsible for a symptom, especially if it involves portion of the brain that are close in proximity to other systems, such as the limbic system. For example, while the hippocampus was emphasised in this particular blog post, it itself is influenced by the hypothalamus-pituitary-adrenal (HPA) axis (Shimko and James, 2025). All in all, it seems that treating the root cause of neurodivergence and other DSM-5 disorders, will have to be a multipronged effort.
Blog Post 9 →