Inside the Mind: Investigating the Brain Scans of Anxiety, Depression, and PTSD

Depression, Anxiety, and PTSD are currently the most common mental illnesses, impacting over 970 million people worldwide. While many are familiar with the symptoms of these disorders, fewer realize that they are characterized by distinct physical and chemical changes in the brain. By gaining an understanding of the neurobiological basis of these conditions, we can help reduce the stigma surrounding them and foster an environment that encourages individuals to seek the help they need.

Anxiety

Anxiety vs no Anxiety (above)                                    Anxiety vs no Anxiety (below)

Looking at the brain scans above, areas with white or red (left) or red and yellow (right) represent the areas where the brain is most active, while blue indicates average activity. As shown, in a healthy brain, the most active area is the cerebellum, which is important for movement and coordination. However, in an anxious brain the basal ganglia display overactivity. Due to the fact that the basal ganglia play a key role in decision making, learning, and the development of habits, overactivity in this region may cause individuals with anxiety to develop maldaptive thinking patterns that contributes to excessive worry and a tendency to predict the worst. 

Depression

Normal vs depressed brain (above)                   Normal vs depressed brain (below)

As shown in the images above, depression is characterized by a reduction in activity in certain brain areas, including the prefrontal cortex, which is important for executive functioning, and the hippocampus, which plays a key role in emotional processing and regulation. Individuals with depression also exhibit increased activity in the amygdala, another structure closely involved in emotion. Chronic stress is one factor that is believed to contribute to the development of depression, as persistent stress can impact the brain’s ability to cope and make the amygdala more responsive to negative stimuli, resulting in persistent sadness.

Post Traumatic Stress Disorder (PTSD)

PTSD vs no PTSD (above)                                               PTSD vs no PTSD (below)

The first PET scan indicates that one key difference in a brain with PTSD when compared to a healthy brain, is an increased amount of a specific glutamate receptor, mGluR5.. This receptor is associated with fear and stress-related behaviors, which could explain why individuals with PTSD may react fearfully or aggressively in response to certain stimuli. The second scan shows that, similar to those with depression, individuals with PTSD have an overactive amygdala paired with an underactive prefrontal cortex. This may cause those with PTSD to have strong negative reactions to stimuli that wouldn’t normally provoke a response in people with a typical amygdala and prefrontal cortex.

Seeing the distinct differences between normal brains and the brains of individuals with mental illness, it may be easy to assume that recovery isn’t possible once mental illness has developed. In reality, that is a complete myth. With proper treatment, these brain changes can be reversed, and while it may look different for each person, recovery is achievable.