Understanding stress: characteristics and caveats.

Exposure to stressful situations is among the most common human experiences. These types of situations can range from unexpected calamities to routine daily annoyances. In response to stressors, a series of behavioral, neurochemical, and immunological changes occur that ought to serve in an adaptive capacity. However, if those systems become overly taxed, the organism may become vulnerable to pathology. Likewise, the biological changes, if sufficiently sustained, may themselves adversely affect the organism's well-being. Several factors may dictate an individual's response to environmental stressors, including characteristics of the stressor (i.e., type of stressor and its controllability, predictability, and chronicity); biological factors (i.e., age, gender, and genetics); and the subject's previous stressor history and early life experiences. Research on the physiological and psychological responses to different types of stressful stimuli is presented, focusing particularly on processes that may be relevant to the development of alcohol use disorders. Stressful events may profoundly influence the use of alcohol or other drugs (AODs). For example, the resumption of AOD use after a lengthy period of abstinence may reflect a person's attempt to self-medicate to attenuate the adverse psychological consequences of stressors (e.g., anxiety). Alternatively, stress may increase the reinforcing effects of AODs.