Towards a Mechanistic Understanding of Depression, Anxiety, and Their Comorbidity: Perspectives from Cognitive Neuroscience

Depressive and anxiety disorders are among the most common and disabling mental disorders. Over and above that, these two disorders are often comorbid: over half of patients with depressive disorders also have one or more anxiety disorders, and vice versa. Comorbid depression and anxiety causes more severe distress, and often results in poor treatment responses. Research so far has generally found that psychological risks factors and neurobiological alterations across the two disorders are similar. Common psychological risk factors for the two disorders include stressful life events, adversity, and neuroticism. Common neurobiological alterations include abnormalities in the prefrontal-limbic pathways, the serotonergic projections, and the hypothalamic–pituitary–adrenal (HPA) axis. There is, however, a lack of understanding of how the two disorders differ from each other and from their comorbidity. This knowledge is essential for the development of individualized clinical treatment and preventive interventions. Several recent studies from cognitive neuroscience have provided promising insights into the differential mechanisms of the two disorders. For instance, studies in the field of decision-making suggest that depressive disorders are primarily driven by a lack of response to reward or tendency to seek reward, while anxiety disorders are primarily driven by enhanced response to threat or tendency to avoid threat. Similar insights have been provided by several studies using other cognitive neuroscience paradigms, such as attention, affective processing, and neuroimaging techniques. These studies, however, are limited by their small sample size and their inability to exclude the influence of important confounding factors such as sex, age, socioeconomic status, and the comorbidity with other psychiatric disorders.

The goal of this Research Topic is to advance these preliminary insights, promote our understanding of the unique versus common mechanisms of depression and anxiety, and clarify the driving forces of their comorbidity from the cognitive neuroscience perspective. This will facilitate the identification of novel treatment targets, the development of novel non-pharmacological (e.g., psychological, behavioral, dietary, or neuromodulatory) therapies, and the planning of clinical management and treatment as well as prevention of the disorders.

The following subtopics are particularly welcome:

• Studies of decision-making.
• Affective (cognitive) neuroscience studies .
• Studies of working memory and executive functioning.
• Methodologies might include, but not limited to: behavioral, eye-tracking, electrophysiological, and neuroimaging studies.

Article types include, but are not limited to, Original Research, Brief Research Reports, Clinical Trials, Case Reports, Review Articles, meta-analyses, and Hypothesis and Theory articles.