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Week 2: Psychopathology - Biological Models (What makes a person abnormal?…
Week 2: Psychopathology - Biological Models
What makes a person abnormal? Why are the abnormal?
Biological
AKA - Medical Mode
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Main Assumptions: (1)
Abnormal behaviour, thinking, and emotional are caused by biological dysfunctions
(2)
Understanding mental illness involves understanding what went wrong with the brain
Possible causes: (1) Biochemistry
- an imbalance of certain neurtransmitters or hormones might cause part of the brain to malfunction (
2) Structural damage or abnormality
- if the structure of the brain is damaged or improperly formed then thinking , emotion and behaviour may change
(3) Genetics (4) Toxicity
- chemical changes to the brain,
(5) Infection/diseases (6) Stress
(3)
Genetics factors
- inherited disposition (causitive?),
Biochemistry
- excessive amounts of certain biochemicals eg dopamine - schizophrenia, seratonin - depression
Neuroanatomy - brain damage or inherited structural/organisational defects eg autism
Evidence of Biological Model -Twin studies very common, with all mental illnesses with a genetic link are more common in monozygotic twins than dyozygotic twins
No 2 studies have replicated exact results so a lot not understood yet to declare causation
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Developmental/socio-cultural
Cognitive
Behavioural
Evidence for Biological Model Continued -
Biochemistry
- a number of psychiatric disorders are associated with abnormal levels of neurotransmitters,
Schizophrenia
-too much dopamine
ADHD
- too little dopamine
Evidence for Dopamine Hypothesis
- Amphetamines induce psychotic symptoms
Neuroleptic medications (particularly those with DA binding site affinity ameliorate psychotic symptoms
-dopamine metabolite (eg HVA) levels correlate with severity of psychosis and treatment response
Medications may work but could be lots of reasons (causation) eg headache
Modern brain scans can tell you a lot about abnormalities, Autopsy, MRI, PET
Not purely biological
SZ example
Enlargement of lateral ventricles on a CT - robust results
Treatment
Designed to change brain function
Pharmacological (Drugs)
- Problems - no money into better, don't cure, have a short window or only partially uses
Electroconvulsive Therapy
- short duration current through the brain, works well with some forms of depression, extended use can result in memory loss.
Psychosurgery
- cutting, removing or destroying part of brain , not used very often now, was used in depression, SZ and OCD
Neurofeedback
- changing brainwave - ADHD - some proficiency but still needs work
Genetic Counselling -
used if parent are carrier of a gene that could be disadvantageous, used to make informed family planning, cannot cure a disease.
Limitations
- not all behaviour responds to simply biology , needs to be evaluated within the context of other factors