stressor

Meaning: A stressor is the stimulus, any event, condition or demand, that triggers the stress response. Stress is the reaction. In the appraisal model (Lazarus), primary appraisal judges whether an event is irrelevant, benign, or stressful (threat, harm or challenge); secondary appraisal judges whether one has the resources to cope. Stressors include catastrophes, major life changes, chronic strain and daily hassles. Eustress follows positive events, distress negative ones.

On the MCAT: Passages describe a situation, such as exams or job loss, and ask you to separate the stressor from the response, or to predict how appraisal, social support or a sense of control changes the outcome. Selye's general adaptation syndrome tracks a prolonged stressor through alarm, resistance and exhaustion.

Common confusion: Anxiety, a racing heart and cortisol release are the stress response, not the stressor. Also, an event is not stressful by itself: appraisal decides whether it counts as a stressor, so the same event can be a threat to one person and a challenge or irrelevant to another.