The Source of Anxiety

After hearing Dr. Heller’s talk on their paper, “Transdiagnostic dimensions of anxiety: Neural mechanisms, executive functions, and new directions”, which describes the link between psychological and neurobiological anxiety models, I was left with questions as to why some people experience more anxiety than others. It is proposed that anxious arousal should be thought of as a propensity to experience state fear more often and more easily, but why does this happen to some people and not others? Do people with high anxious arousal have a lower threshold for sympathetic nervous system arousal than a person who is only stimulated if they feel threatened? Or does the system become hyperactive when feeling threatened? 

Fear and anxiety can be distinguished from each other in that the object of fear is ‘real’ or ‘external’ and the origins of anxiety are unclear, but the sense of uncontrollability focused on possible future threats, danger or other upcoming  potentially negative events, whereas in fear, the danger is present and imminent (Steimer). Increased anxiety, as a trait, can be attributed to at least two factors. The first is a genetic predisposition linked to gene expression involved in neurochemical mechanisms underlying anxiety and fear. The second  is environmental factors that can interact with relevant genes during early development and influence the functional properties of biochemical and neural systems used when coping with stress. These can also modulate the learning processes later in life and the capacity to successfully adapt to aversive or threatening situations. Prenatal stress in animals has been shown to cause permanent alterations in brain morphology, anxiety related behavior and coping into adulthood. 

While I couldn’t not find a specific answer to all of my questions, I did find that it is a combination of genetic predisposition and environmental influences that can cause some individuals to have a greater fear of unknown or uncontrollable circumstances. The study of genetic predisposition and environmental influences, during early development, in determining vulnerability traits and anxiety prone endophenotypes is becoming a promising research area with respect to a further understanding of anxiety and mood disorders. 

Sharp, Paul B, et al. “Transdiagnostic Dimensions of Anxiety: Neural Mechanisms, Executive Functions, and New Directions.” International Journal of Psychophysiology : Official Journal of the International Organization of Psychophysiology, U.S. National Library of Medicine, Nov. 2015, www.ncbi.nlm.nih.gov/pubmed/26156938.

Steimer, Thierry. “The Biology of Fear- and Anxiety-Related Behaviors.” Dialogues in Clinical Neuroscience, Les Laboratoires Servier, Sept. 2002, www.ncbi.nlm.nih.gov/pmc/articles/PMC3181681/.