General Adaptation Syndrome (GAS) in AP Psychology

General Adaptation Syndrome (GAS) is Hans Selye's model of how the body responds to stress over time, moving through three stages: alarm reaction, resistance, and exhaustion. The greatest susceptibility to illness comes in the exhaustion stage (AP Psych Topic 5.1).

What is General Adaptation Syndrome (GAS)?

General Adaptation Syndrome (GAS) is Hans Selye's description of what your body goes through when stress hits and sticks around. Think of it as a timeline of stress, not a single moment. The AP CED breaks it into three phases:

1. Alarm reaction. You first encounter the stressor, and your body kicks into a fight-flight-freeze response. Heart rate climbs and energy gets mobilized.
2. Resistance. You confront the stressor. Your body stays revved up and tries to adapt, holding that heightened state for as long as it needs to.
3. Exhaustion. The stress finally subsides, or your resources simply run out. This is the danger zone. The CED says the greatest susceptibility to illness occurs during the exhaustion phase.

A simple way to picture it is a phone battery. Alarm is the moment you open a power-hungry app. Resistance is the battery steadily draining while you keep using it. Exhaustion is the battery hitting 2%, when everything starts glitching. That "glitching" is why GAS connects stress to things like weakened immunity and getting sick right after a big stressful stretch.

Why General Adaptation Syndrome (GAS) matters in AP® Psychology

GAS lives in Unit 5: Mental and Physical Health, under Topic 5.1 Introduction to Health Psychology. It is named directly in the essential knowledge for AP Psych 5.1.C, which asks you to explain how reactions to stress apply to behavior and mental processes. It also backs up AP Psych 5.1.B, since the exhaustion stage is the mechanism behind the CED's claim that stress raises susceptibility to disease (hypertension, headaches, immune suppression). And it sets up AP Psych 5.1.D, because coping strategies are basically ways to keep yourself from sliding into exhaustion. GAS is the bridge between "stress feels bad" and "stress can actually make you sick," which is the whole point of health psychology.

How General Adaptation Syndrome (GAS) connects across the course

Fight-or-Flight Response (Units 1 and 5)

Fight-or-flight is not a separate idea from GAS. It IS the alarm reaction. The sympathetic nervous system activation you learn about in biological psychology is what powers stage one, so GAS is really fight-or-flight stretched out over days or weeks.

Daily Hassles and Adverse Childhood Experiences (Unit 5)

The CED says small daily hassles can build up over time and ACEs can affect a person across the lifespan. GAS explains why. Stress that never fully lets up keeps you stuck in resistance, slowly draining resources until exhaustion and illness become more likely.

Problem-Focused and Emotion-Focused Coping (Unit 5)

If GAS describes the drain, coping is how you plug the leak. Problem-focused coping tries to remove the stressor, while emotion-focused coping (deep breathing, meditation) calms your reaction. Either way, the goal is to avoid hitting the exhaustion stage.

Tend-and-Befriend Theory (Unit 5)

The CED pairs GAS with tend-and-befriend as two ways of describing reactions to stress. GAS focuses on the body's physical stages, while tend-and-befriend highlights that some people respond by caring for others and seeking connection instead of fighting or fleeing.

Is General Adaptation Syndrome (GAS) on the AP® Psychology exam?

Expect GAS in two main forms. On MCQs, you'll usually get a scenario and need to identify the stage. Someone who just got terrible news and has a racing heart is in alarm. Someone grinding through weeks of a stressful job is in resistance. Someone who finally gets sick after finals week is in exhaustion. Questions also love to test the fact that illness risk peaks in exhaustion, not alarm.

On FRQs, you apply GAS to a real situation. The 2018 SAQ Q2 described a survey of high school students' physical and psychological health, including student stress levels and absences. That's exactly the kind of setup where GAS fits. You could explain that students under prolonged stress move from resistance into exhaustion, which raises their chance of getting sick and missing school. The key move is to name the stage AND tie it to the specific behavior in the prompt. Just defining GAS won't earn the point.

General Adaptation Syndrome (GAS) vs Fight-or-Flight Response

Fight-or-flight is the body's immediate burst of arousal when it detects a threat. GAS is the bigger, longer process that fight-or-flight kicks off. Fight-or-flight only covers the alarm reaction, the first of three stages. If a question is about what happens over an extended period of stress, or about getting sick afterward, it's asking about GAS (specifically resistance or exhaustion), not fight-or-flight.

Key things to remember about General Adaptation Syndrome (GAS)

• General Adaptation Syndrome is Hans Selye's three-stage model of how the body responds to stress over time.

• The three stages, in order, are alarm reaction, resistance, and exhaustion.

• The alarm reaction is driven by the fight-flight-freeze response when a stressor first appears.

• In the resistance stage, the body stays aroused while it confronts and tries to adapt to the stressor.

• The greatest susceptibility to illness occurs during the exhaustion stage, after the stress subsides or resources are spent.

• On the exam, you should be able to identify the GAS stage in a scenario and connect it to a health or behavioral outcome.

Frequently asked questions about General Adaptation Syndrome (GAS)

What is General Adaptation Syndrome in AP Psychology?

General Adaptation Syndrome (GAS) is Hans Selye's model of the body's response to stress, moving through alarm reaction, resistance, and exhaustion. It appears in AP Psych Topic 5.1 under learning objective 5.1.C.

Are you most likely to get sick during the alarm stage of GAS?

No. According to the AP CED, the greatest susceptibility to illness occurs during the exhaustion phase, when the stress has subsided or your resources are spent. Alarm is the initial fight-flight-freeze burst, not the point of maximum vulnerability.

How is General Adaptation Syndrome different from fight-or-flight?

Fight-or-flight is a short-term arousal response, and it only matches the first GAS stage, the alarm reaction. GAS describes the full process over time, including resistance and exhaustion.

What are the 3 stages of GAS in order?

Alarm reaction comes first, when the stressor is encountered. Resistance comes next, as the stressor is confronted. Exhaustion is last, when the stress subsides or resources run out.

Is General Adaptation Syndrome on the AP Psych exam?

Yes. GAS is named directly in the essential knowledge for AP Psych 5.1.C in Unit 5. Stress-related prompts like the 2018 SAQ Q2, which focused on high school students' stress levels and absences, are a natural place to apply it.