Stress and Addiction: Updates on the Chicken or Egg question

Addiction models highlight stress as a key risk factor for developing drug addiction and for relapse, maintaining the vicious circle of drug addiction. Accumulating evidence from animal and human studies indicates that substances such as cocaine, opioids, and alcohol directly affect acute physiological stress responses, notably the hypothalamic-pituitary adrenal axis and the endocannabinoid system. The present symposium will give an update on the key “Chicken or Egg” question in addiction: which came first, altered stress response entailing substance use as a coping mechanism; or substance induced changes in the stress response system maintaining drug addiction and relapse; or both? The symposium combines clinical and basic human addiction science perspectives. First, Dr. Kexel will present novel results on acute stress response and its interaction with craving in chronic cocaine users. Second, Dr. Kroll will show recent findings about changes in the stress (endocannabinoid) system in chronic cocaine and opioid users on a tonic and phasic level after acute stress-induction. Third, Dr. Mayo will discuss how chronic stress induced by childhood trauma might alter the stress (endocannabinoid) system and facilitate or protect the development of substance use disorder. Fourth, Dr. Carlyle will follow up on childhood trauma as a potential risk factor for addiction with data on acute and chronic drug effects in individuals with severe early childhood trauma. Fifth, Prof. Leknes will present basic and clinical data on acute stress effects on opioid drug liking. In sum, study findings presented in this symposium will indicate that preexisting altered stress response, induced by acute or chronic stress, might be a crucial precursor for developing substance use disorders. Results will further suggest that adequate stress coping on a psychological (craving) and neurobiological level (endocannabinoid system) might play a key role in preventing as well as breaking the vicious circle of drug addiction.