Health psychology (option): Selye's General Adaptation Syndrome

Origins

In the 1930s Hans Selye, researching hormones in rats, noticed that rats exposed to many different prolonged stressors (extreme cold, surgical injury, excessive exercise, shock) showed the same pattern: enlarged adrenal glands, shrunken thymus and lymph nodes, and stomach ulcers. He concluded the response is non-specific: the body reacts the same way whatever the stressor. He called it the General Adaptation Syndrome (GAS).

The three stages

Evaluation

• Strengths: the first model linking prolonged stress with illness; supported by later research on cortisol and immune suppression; practical application (recognising early signs of chronic stress).
• Weaknesses: based on rats, and the stressors were physical, so it may not generalise to human psychological stress; it ignores cognitive appraisal (people react differently to the same stressor, as Lazarus argued); responses are not completely non-specific (different stressors and emotions produce different hormone patterns); exhaustion may be due to cortisol's effects rather than resources 'running out'.

Worked example

A nurse has worked long night shifts for months. She coped at first but now has frequent colds and feels drained. Explain using the GAS.

1. At first, the **alarm reaction** gave a burst of energy (adrenaline).
2. Over the following weeks she was in **resistance**: coping on high cortisol.
3. Now she is in **exhaustion**: resources are depleted and her immune system is suppressed, so she catches colds.

Answer: Alarm, then resistance, now exhaustion.

Check yourself

1. Which is the first stage of the General Adaptation Syndrome?
   • Resistance
   • Exhaustion
   • Appraisal
   • Alarm reaction
   Show answer

   Alarm reaction. Alarm comes first.

2. In the resistance stage, the body
   • returns completely to normal
   • adapts to the continuing stressor, with cortisol kept high
   • has run out of resources
   • has not yet detected the stressor
   Show answer

   adapts to the continuing stressor, with cortisol kept high. Adaptation while resources are used.

3. Illness is most likely in which stage?
   • Alarm reaction
   • Resistance
   • Illness never follows stress in the GAS
   • Exhaustion
   Show answer

   Exhaustion. Depleted resources make illness likely.

4. Selye described the stress response as non-specific. This means
   • the body responds in the same way whatever the stressor
   • every stressor causes a different response
   • only physical stressors cause stress
   • the response only happens in rats
   Show answer

   the body responds in the same way whatever the stressor. The same pattern for any stressor.

5. Which criticism of the GAS relates to generalisability?
   • It has three stages
   • It mentions the alarm reaction
   • It was based on rats exposed to physical stressors
   • It links stress with illness
   Show answer

   It was based on rats exposed to physical stressors. Rats and physical stressors may not represent human psychological stress.

6. Explain one weakness of Selye's General Adaptation Syndrome.
   Show answer

   It ignores cognitive appraisal: people respond differently to the same stressor depending on how they interpret it, so the response is not the same for everyone as the GAS suggests.. Name the weakness and why.

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Sources

• Pearson Edexcel International Advanced Subsidiary/Advanced Level in Psychology specification, Issue 6 (November 2024, first assessment January 2026)
• Penn State Kinesiology open text: Selye's general adaptation syndrome
• OpenStax Psychology: 14.1 What is stress? (HPA axis, cortisol, general adaptation syndrome)

Last updated 8 November 2026. Spotted a mistake? Tell us.