Stress Sensitivity as a Biological Marker for Depression
Depression can be regarded as emotion dysregulation and heightened reactivity to stress. It is a cognitive, affective and biological response to stressors, negative events, or negative stimuli. People who have depression have a different cognitive processing in two ways – increased attention to negative stimuli and attention biases for sad and angry faces. When depressed people have increased attention to negative stimuli, they are unable to inhibit processing of negative stimuli and to expel negative stimuli. They have better memory, sensitivity, and reactivity to negative stimuli, but poorer memory for positive stimuli. When depressed people have attention biases for sad and angry faces, they pay more attention to sad faces over happy faces. One longitudinal study discussed during the presentation included “high-risk” girls 10-14 years old who had no personal history of depression but whose mothers had been diagnosed with depression. When shown pictures of faces with different emotions, the girls with a family history of depression had more activation in the amygdala when shown sad faces, compared to a control group of girls with no family history of depression. Post-experiment, the brains of the high-risk girls looked virtually the same as a depressed adult, and their neuro-responses resembled those of a person with depression, even though the girls reported no sadness. Although these results confirmed family history is still the strongest risk factor for depression, it is suggested that attention bias training can help these girls improve their mood.