Psychology and defence mechanisms

Classical conditioning

• A neutral stimulus repeatedly paired with an unconditioned stimulus comes to produce the response on its own (the conditioned response). Clinical examples: anticipatory nausea before chemotherapy, phobias, white-coat hypertension.
• Extinction: the conditioned response fades when the conditioned stimulus is repeatedly presented alone. Generalisation: the response spreads to similar stimuli. Spontaneous recovery can follow extinction.

Operant conditioning

Behaviour is shaped by its consequences.

• Schedules: continuous reinforcement gives fast learning and fast extinction; variable ratio is the most resistant to extinction (gambling). Shaping reinforces successive approximations.
• Observational (social) learning: learning by watching and imitating models (children copying parental smoking); self-efficacy is belief in one's ability to succeed.
• Learned helplessness: repeated uncontrollable adverse events lead to passivity, a model of depression.
• Behaviour therapy: systematic desensitisation (graded exposure with relaxation, for phobias), flooding, aversion therapy (disulfiram with alcohol), token economy, biofeedback, exposure and response prevention (OCD).

Memory

• Declarative (explicit) memory, episodic (events) and semantic (facts), depends on the hippocampus and medial temporal lobe. Procedural (implicit) memory for skills depends on the basal ganglia and cerebellum, so it survives hippocampal damage.
• Forgetting: decay, interference (proactive: old blocks new; retroactive: new blocks old), retrieval failure, repression.
• Primacy and recency: first and last items are remembered best, so give key advice first and repeat it at the end; patients forget much of what they are told, so add written information.
• Anterograde amnesia: cannot form new memories (hippocampal damage, Korsakoff syndrome, benzodiazepines). Retrograde amnesia: loss of memories before an event (head injury, ECT), recent memories lost first (Ribot's law). Arousal depends on the reticular activating system; memory formation on the hippocampus.

Development and attachment

• Attachment (Bowlby, tested by the "strange situation"):

Personality

• Big Five traits: openness, conscientiousness, extraversion, agreeableness, neuroticism.
• Type A personality: competitive drive, time urgency, impatience and hostility. Hostility and anger drive repeated sympathetic surges, catecholamine release and hypertension, raising coronary heart disease risk. Type B is relaxed; type D is distressed (negative affect with social inhibition).
• Locus of control: internal (outcomes depend on my actions; better health behaviour) versus external (luck, fate, doctors).
• Assessment: objective self-report questionnaires are scored against norms, for example the MMPI (Minnesota Multiphasic Personality Inventory) and the Eysenck Personality Questionnaire. Projective tests (Rorschach inkblots, Thematic Apperception Test) present ambiguous stimuli and are interpreted. IQ tests (Wechsler scales) measure intelligence: mean 100, SD 15; intellectual disability is IQ below 70 with adaptive deficits.

Personality disorders

Defence mechanisms

Unconscious strategies that protect the ego from anxiety.

Stress

• Eustress is positive stress that motivates, leading to growth and better performance; distress is harmful stress that exceeds coping.
• Yerkes–Dodson law: performance rises with arousal to an optimum, then falls (inverted U).
• Physiology: the hypothalamic–pituitary–adrenal axis (CRH, ACTH, cortisol) and the sympathetic–adrenomedullary system (catecholamines). Stress of surgery raises cortisol, catecholamines, ADH, glucagon and GH, causing hyperglycaemia, sodium and water retention, vasoconstriction, leucocytosis and eosinopenia. Anxiety can raise heart rate with normal blood pressure.
• General adaptation syndrome: alarm, resistance, exhaustion.
• Life events: on the Holmes–Rahe scale death of a spouse scores highest. Chronic stress contributes to hypertension, coronary disease, peptic ulcer flares, tension headache, irritable bowel, immunosuppression, depression and burnout (emotional exhaustion, depersonalisation, reduced accomplishment).
• Stress of hospitalisation comes from loss of control and privacy, separation from family, unfamiliar surroundings, fear of the unknown and pain.

Coping

• Primary appraisal (is this a threat?) and secondary appraisal (can I cope?).
• Problem-focused coping acts on the stressor (planning, seeking information); best for controllable problems. Emotion-focused coping manages feelings (acceptance, relaxation, support); useful for uncontrollable problems.
• Social support buffers stress; hardiness (commitment, control, challenge) and resilience protect. Maladaptive coping includes substance use and avoidance.
• Motivational interviewing applies these ideas: the doctor explores the patient's own reasons for change, reflects ambivalence and avoids lecturing.

Remember Reinforcement, positive or negative, always increases behaviour; punishment decreases it.

Exam trap Negative reinforcement removes something unpleasant; it is not punishment.

Exam trap Objective tests such as the MMPI are scored; projective tests such as the Rorschach are interpreted.

How FCPS asks about this

• Anticipatory nausea before chemotherapy: classical conditioning.
• Most extinction-resistant schedule: variable ratio (gambling).
• Child distressed when mother leaves, easily comforted on return: secure attachment.
• Lying, theft, forgery, no remorse, teenage conduct disorder: antisocial (dissocial) personality disorder.
• Stress that leads to growth and better performance: eustress.
• Self-report personality questionnaire: MMPI.
• Why type A personality causes heart disease: hostility and competitive drive with sympathetic overactivity.