The human nervous system consists of two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS contains the brain and spinal cord. The PNS consists mainly of nerves, long fibers that connect the CNS to every other part of the body so that information can be sent back and forth between the brain and the entire body. The autonomic nervous system (ANS) is part of the peripheral nervous system and acts as a control mechanism for most internal organs and ordinarily functions below the level of conscious awareness. Active addiction precipitates a massive increase in the activity of the sympathetic division of the autonomic nervous system. The sympathetic division of the ANS is activated under circumstances of perceived threat and sets in motion the chain of physiological responses that prepare the body for “fight or flight.” These unconscious responses automatically put mind and body on high alert, priming for action by initiating hypervigilance, increasing heart rate, constricting blood vessels, increasing blood pressure, dilating pupils, and inhibiting digestion. Fight or flight mode kicks into gear in response to the stress of potential threats, but the nature of these physiological reactions themselves creates additional stress that becomes chronic in active addiction as the stress switch is stuck in the “on” position. This taxes many of the body’s systems, leading to a wired form of exhaustion, a run-down immune system, and greater vulnerability to illness, and yes, stress. This chronic stress response continues during post-acute withdrawal, receding and effectively resetting only gradually over time. As a result, people come into recovery under the influence of biologically birthed higher levels of stress in combination with an enhanced susceptibility to stress. Meanwhile, early recovery can be incredibly stressful in and of itself. All sorts of stressful situations inevitably arise, and the frustration, confusion, and blistering discomfort of post-acute withdrawal symptoms (stress-inducing themselves) piggybacks onto them to produce even more distress. This blog post is an excerpt from Some Assembly Required – A Balanced Approach to Recovery from Addiction and Chronic Pain by By Dan Mager, MSW; Published by Central Recovery Press (CRP).