Chapter 2: An Integrative Approach to Psychopathology

One-dimensional (linear) model
- Traces a disorder to a single cause (e.g., “chemical imbalance”).
- Ignores context & interactions.
Multidimensional integrative model
- Behaviour, cognition, emotion, biology, social & cultural forces, and developmental stage all interact.
- System/feedback-loop: once an influence enters the loop it no longer remains independent.
- Judy’s blood–injection–injury phobia used as running illustration of interwoven causes.

Genes: long DNA molecules arranged in $23$ chromosome pairs; first $22$ = autosomes, last pair = sex chromosomes.
Dominant vs. recessive traits; most behaviour is polygenic (many genes, small effects each).
Genome size: $\approx 20{,}000$ genes; $\approx 160\,\text{million}$ base pairs on X chromosome.
Quantitative genetics assesses aggregate influence; molecular genetics pinpoints networks via DNA microarrays.
Heritability
- Personality & cognitive traits $\approx 30\%-60\%$ genetic.
- Every major mental disorder shows some genetic liability but usually < $50\%$ .
New findings
- Short (S) vs. long (L) alleles of 5-HTT gene: S/S + severe stress $\Rightarrow$ doubled depression risk.
- Gene × Environment (G×E) interactions common (diathesis–stress & reciprocal models).
Epigenetics
- Environment (stress, maternal care) can switch genes on/off via methylation; changes can be heritable yet reversible.
- Cross-fostering in rats & rhesus monkeys: rearing quality overrides genetic temperamental risk.

CNS: brain + spinal cord. 100–140 billion neurons, trillions of synapses.
- Neuron anatomy: dendrite (input) – cell body – axon – terminal button – synaptic cleft.
Major brain divisions
- Hindbrain (medulla, pons, cerebellum)
- Midbrain (reticular activating system)
- Forebrain: limbic system (amygdala, hippocampus, cingulate), basal ganglia, cerebral cortex (4 lobes; prefrontal = planning/meaning).
Peripheral NS
- Somatic (voluntary muscles)
- Autonomic → sympathetic (fight/flight) & parasympathetic (rest/digest); links to endocrine system (HPA axis).
HPA axis: hypothalamus $\rightarrow$ pituitary $\rightarrow$ adrenal cortex $\rightarrow$ cortisol; dysregulated in depression/PTSD.
Neurotransmitters
- Glutamate (excitatory) & GABA (inhibitory) – “chemical brothers”.
- Serotonin (5-HT): mood, information processing; low 5-HT = impulsivity, aggression; SSRIs block reuptake.
- Norepinephrine: alarm reactions; beta-blockers inhibit cardiovascular effect.
- Dopamine: reward, locomotion; hyper-dopaminergic activity implicated in schizophrenia; hypo in Parkinson’s.
Agonist / antagonist / inverse agonist / reuptake inhibition – drug mechanisms.

Experience alters circuitry (neuroplasticity): enriched cages ↑ dendritic complexity; stress ↓ neurogenesis.
Psychotherapy changes brain
- CBT for OCD normalised hyper-activity in orbital frontal–cingulate–caudate loop.
- Imaging shows “top-down” cortical changes after CBT vs. “bottom-up” changes after medication.
Placebo effects engage the same ACC & brain-stem pain circuits as opioids.

Classical conditioning revisions
- Contiguity insufficient; cognitive expectancy (Rescorla) determines learning strength.
Learned helplessness / learned optimism (Seligman) – attribution of controllability modulates stress & depression.
Modeling (observational learning) – Bandura’s Bobo doll → behaviour learned vicariously.
Prepared learning – biologically primed fears (snakes, spiders) & one-trial taste aversion.
Implicit memory & unconscious cognition – actions guided by stored info outside awareness (e.g., blindsight, Stroop paradigm).

Components: physiology, behaviour, cognition.
Fight-or-flight: sympathetic surge; adaptive but pathogenic if misfiring (e.g., panic attacks).
Mood vs. affect: persistent emotional tone vs. momentary expression; circumplex (valence × arousal).
Anger & heart: anger episodes ↓ left-ventricular ejection fraction; forgiveness mitigates cardiovascular stress.

Fright disorders (susto, evil eye, voodoo death) – culturally bound fear syndromes.
Gender roles shape disorder presentation: 90 % of animal/insect phobias female; equal social phobia; bulimia largely female.
Social support
- Larger networks ↑ longevity, ↓ colds & depression.
- Isolation risk comparable to smoking.
Urbanicity & schizophrenia: urban upbringing doubles risk.
Elderly: perception of shrinking network predicts depression; illness may paradoxically elicit needed support.

Developmental stage modifies risk & expression (e.g., SSRIs effective in adults but risk in youth).
Equifinality: multiple paths $\rightarrow$ same disorder (e.g., delusions via schizophrenia or amphetamine abuse; autism via rubella or labor trauma).
Protective “resilience” factors: secure attachment, supportive adult, sense of purpose.

No single cause explains psychopathology.
Disorders arise from dynamic interaction among:
1. Biological (genes, NTs, brain circuits)
2. Psychological (learning history, cognition, emotion regulation)
3. Social & cultural (family, gender, SES, stigma)
4. Developmental timing (critical periods, age-specific vulnerabilities)
Clinical assessment & treatment must address all dimensions for full understanding and effective intervention.