Pain

The key insight of pain psychology is that pain is not a simple readout of injury.

Pain ≠ tissue damage. The amount of pain felt does not match the amount of injury in a fixed way. Soldiers with serious wounds sometimes report little pain; people with no injury (e.g. phantom limb pain) can feel severe pain. Pain is a psychological experience influenced by:

• attention (focusing on pain increases it; distraction reduces it),
• emotion/mood (anxiety and low mood worsen pain),
• context and meaning (the same sensation hurts more if it signals threat),
• expectation (the placebo effect can reduce pain).

Why this matters. Because pain is psychological as well as physical, it can be measured by asking about the experience and managed by changing attention, thoughts and mood — not only with drugs. This is exactly what the gate control theory explains.

Why this matters for the exam. Hold the idea that pain is a psychological experience modifiable by the mind: it explains why psychological measurement and psychological management make sense, and underpins the gate control theory.

Acute vs chronic.

• Acute pain — short-term, comes on suddenly, usually has a clear cause (injury/illness) and acts as a warning; it fades as healing occurs.
• Chronic pain — persists long-term (often defined as more than 3–6 months), may continue after healing, and is harder to treat; it can be chronic benign (recurrent, e.g. back pain) or chronic progressive (worsening, e.g. cancer pain).

Organic vs psychogenic.

• Organic pain — has an identifiable physical cause (tissue damage).
• Psychogenic pain — pain with no clear physical cause, thought to be linked to psychological factors. (This is a difficult, sometimes stigmatising category.)

Phantom limb pain. Pain felt in a limb that has been amputated. It shows pain can be generated centrally (in the brain/nervous system) without input from the body part — strong evidence against simple 'pain = signal from injury' theories.

Evaluation in brief. These categories are clinically useful, but the organic/psychogenic split is problematic (it can imply psychogenic pain is 'not real'), and pain is often mixed (both physical and psychological), so rigid categories oversimplify.

Gate control theory (Melzack & Wall, 1965) is the key pain theory because it explains the psychological influence on pain.

The idea. There is a 'gate' (a neural mechanism in the dorsal horn of the spinal cord) that controls whether pain signals reach the brain:

• when the gate is open, signals pass through and pain is felt;
• when the gate is closed, signals are blocked and pain is reduced.

What opens and closes the gate:

• Physical factors — activity in large (touch) nerve fibres can close the gate (which is why rubbing a knock helps); injury/inflammation opens it.
• Psychological factors (top-down, from the brain):
  • Closing the gate: distraction, relaxation, positive mood, focusing elsewhere.
  • Opening the gate: anxiety, attention to the pain, low mood/depression.

Why it's powerful. It explains how the same injury can hurt differently, why distraction and mood change pain, and phantom limb pain (central mechanisms). It justifies psychological pain management.

Evaluation in brief. Gate control is well-supported and integrates physical and psychological factors (a strength over older specificity theory), and it has clear application (e.g. TENS machines, distraction). But the exact physiology of the 'gate' is simplified/not fully mapped, and it doesn't fully explain all chronic/phantom pain (later neuromatrix theory extends it).

Because pain is subjective, measuring it is challenging.

Self-report measures:

• McGill Pain Questionnaire (MPQ; Melzack) — patients choose from word lists describing pain on sensory (e.g. 'throbbing'), affective (e.g. 'sickening') and evaluative (e.g. 'intense') dimensions, giving a rich, multidimensional picture.
• Visual analogue scale (VAS) — mark pain on a 0–10 line ('no pain' to 'worst imaginable').
• Numerical/verbal rating scales and pain diaries.
  • + Capture the subjective experience directly; quick. − Subjective, affected by mood/desire to please, hard to compare between people.

Behavioural (observational) measures:

• Recording pain behaviours — grimacing, guarding, limping, rubbing, verbal complaints (e.g. the UAB pain behaviour scale).
  • + Objective, useful when self-report is impossible. − Behaviours can be faked/suppressed and don't capture the inner experience.

Measuring pain in children:

• Faces scales (e.g. Wong–Baker FACES — choosing a face from happy to crying) and observational tools, because young children can't use numerical scales.
  • + Age-appropriate, simple. − Faces may reflect mood/fear, not just pain.

Evaluation in brief. Self-report has high validity for the experience but low objectivity; behavioural measures are more objective but miss the inner experience — so combining methods is best.

Biological (medical) management:

• Analgesic drugs (e.g. paracetamol, NSAIDs, opioids) and anaesthetics; surgery in severe cases.
• TENS (transcutaneous electrical nerve stimulation) — stimulates touch fibres to close the gate.
  • + Often fast and effective. − Side effects, tolerance/dependence (opioids), treats the symptom not the cause.

Psychological management (works largely by closing the gate):

• Attention/distraction — focusing away from pain (e.g. VR, music, imagery) reduces it.
• Cognitive strategies — reinterpreting or redefining the pain, positive self-talk, cognitive coping.
• Hypnosis — suggestion to reduce pain perception.
• Biofeedback — using monitored body signals (e.g. muscle tension) to learn relaxation/control.
  • + No drug side effects, give the patient control, useful for chronic pain. − Need effort/skill, effects vary, often best alongside medication.

Pulling it together for Paper 3 'evaluate / discuss':

• Strengths: strong application; gate control gives a holistic (physical + psychological) framework; psychological methods avoid side effects.
• Weaknesses: pain is subjective/hard to measure; psychological methods are variable and need engagement; some evidence is correlational.
• Debates: reductionism vs holism (gate control is holistic vs drug-only views), application, individual differences, idiographic vs nomothetic measurement.