The Biomedical Model Flashcards
What is the biomedical model
- There is no distinction between mental and physical disease
- Mental disorders are biologically based
- Underlying causes are organic
Neurotransmitter Imbalance
- Altered production: over or under stimulating target neuron
- Altered reuptake: Increasing or decreasing concentration at synapses
- Alterations of neurotransmitter receptors: abnormally sensitive or insensitive
Psychotropic Drugs
- Agonist: bund to receptor and produce a similar response to the intended chemical receptor
- Antagonist: drug that binds to the receptor to stop the receptor from producing a response
- treat mental disorder by influence synaptic transmission
Amine Hypothesis of Depression
- Patients given drugs for blood pressure which lead to them experience depressed mood, the drugs were found to be depleting nerve cells of amine neurotransmitters (e.g. serotonin)
- Iproniazid was produced and used to treat depression by increasing amine neurotransmitters
- Depression caused by deficiency of amine neurotransmitters
- Anti depressants work as they increase brain amine levels
- Most anti depressants are SSRIs, block reuptake of serotonin to help increase concentration at synapses in the brain. (Sertraline is most popular)
Criticisms of Amine Hypothesis
- we might not actually have a deficiency of amine.
- oversimplification by saying ‘correct a chemical imbalance’
- inconsistent findings
Types of mental health disorders
- Depression: Amine deficiency. Treated with noradrenaline and serotonin
- Schizophrenia: hallucinations and delusions are due to excess brain dopamine
- OCD: dysfunction in brain pathways regulated by serotonin
Are biological models complex
- dopamine hypothesis of schizophrenia is simplistic and misleading
- biological disease models are highly complex and sophisticated, there is a lot of extensive research
Hormones in mental disorders
Hypothalamic Pituitary Adrenal (HPA) axis
- over active in stress states, including chronic psychological stress
- Leads to persistent elevation of the stress hormone cortisol in the bloodstream
- Implicated in several psychological, disorders (e.g. depression and anxiety)
Generic Vulnerability
- Chromosomal abnormalities, Down syndrome
- Single gene defects, abnormalities in particular genes
- Vulnerability to mental disorder is polygenic (influenced by multiple genes)
Epigenetic’s
- Genetic code is fixed at birth but genes can be switched on and off = epigenetic
- Adverse life experiences can lead to epigenetic changes that influence risk of mental health disorders in adulthood
- However, psychiatric disease risk depends on both genetic and environmental factors
Insulin shock therapy
- 1940s - 1950s for schizophrenic
- insulin is used to induce coma (repeatedly over weeks or months)
- Risks, obesity, seizures, brain damage or death (mortality 5%)
Prefrontal Leukotomy
- cutting white matter in the prefrontal brain
- prefrontal ( part of the brain involved in personality and behaviour)
- Drill while in head and swing blade to cut through nerve fibres
Frontal Lobotomy
- Put instrument into eye socket
- Wiggle the instrument around to separate frontal lobe from rest of the brain
- ‘ice pick’ procedure
Electroconvulsive Therapy (ECT)
- Controlled induction of convulsive seizures under general anaesthesia
- Safe and effective in several disorders (depression and psychosis)
- High relapse rate
- NICE say it is a ‘last resort’ for severe depression
Deep Brain Stimulation (DBS)
- Stimulation of area 25 in the limbic lobe of the brain associated with dramatic mood improvement in severe depression
- Sudden calmness or lightness
- Used for severe treatment resistant conditions (e.g. Depression, OCD)
- Effective but expensive and carries risks
- Last resort
Transcranial Magnetic Stimulation (TMS)
- For treatment resistant depression and anxiety disorder
- Electromagnetic coil delivers magnetic pulses to the brain
- More focused than ECT, target specific areas
- TMS effective for acute depression but not so good as ECT
Pharmacological Treatments
- Psychotropic agents, medications which are able to affect the mind, emotions and behaviour
- Antidepressants, low mood
- Anxiolytics (anxiety)
- Antipsychotics/neuroleptics (psychosis)
- Mood stabilisers (bipolar disorder)
They all influence neurotransmission in the brain
Anti Depressants
- Usually SSRI
- sexual dysfunction, insomnia, nausea
- Common prescribed: fluoxetine, sertraline, paroxetine, citalopram
- Only recommend when no response to psychological treatment
- Withdrawal symptoms
Anti Anxiety Drugs
- Use if CBT fails
- SSRIs and SNRIs
- Pregabalin
- Benzodiazepines, sedative and muscle relaxing properties, cause drowsiness and lethargy, highly addictive and high relapse rates
Antipsychotic Drugs (Neuroleptics)
- Block brain dopamine or serotonin receptors
- Reduce delusions and hallucinations
- Weight gain, diabetes, reduced white blood cells
- Clozapine, Risperidone, Zyprexa
Mood Stabilisers: Lithium
- Bipolar treatment
- very effective 70-80% but can cause toxicity
- Weight gain, fatigue, thirst
- Commonly prescribed, Eskalith and Lithobid
What are some advantaged so Biomedical Model
- Clear mechanisms for most disorders
- Drug treatment is effective and fast
- Scientific method, proven by research
- Double blind randomised control trial - best option
- Meta analysis used to pool results from multiple trials
Limitations of Biomedical Approach
- Assumes universality
- Claims they are brain diseases but scientists have bit identified a biological cause
- Medications work by correcting neurotransmitter imbalances but no evidence that mental disorder is caused by chemical imbalances or that they work by correcting Imbalances
- Mental disorders are becoming more chronic and severe
- Still stigma around mental disorder
Diagnosis of mental disorder
- Has to meet more than diagnostic criteria, clinically significant (impairment of social life).
DSM Major Revisions
DSM 1
- Established mainly by psychoanalysts
- no diagnostic criteria
- Disorders described using ‘prototypes’ which are narrative descriptions of disorder
DSM 2
- symptoms defined as symbolic of unconscious process
DSM 3
- included diagnostic criteria
DSM 3 R
- pressure groups had influence (homosexuality removed)
DSM 4
- Change supported by data and term neurosis dropped
DSM 5
- Influenced by the biomedical model
- Dows not include all possible mental disorders
- Cultural and social context must be considered
- Clinical judgment
- Diagnosis made based of: clinical judgment , DSM criteria and clinical interview
- Limitations, normal grief mixed with depression, overeating labelled as binge eating disorder
- Gender and cultural problems
DSM 5: New disorders/ revisions
New disorder examples: Premenstrual dysphoric disorder, Hoarding disorder
Revisions: Autism spectrum disorder
ICD-10 (1994) & ICD - 11 (2019)
- International Classification of Diseases (WHO)
- for all diseases including mental, behavioural or neurodevelopmental disorders
What are Advantages of Classification
- Facilitates communication between researchers and clinicians
- Enables consistency
- Provides a framework for discussing difficult topics and offering help with sick pay etc.
- Helps to inform decision about allocation of health service resources
- Comfort and relief who no longer feel alone in their experiences
Limitations of Classification
- Some patients may feel disempowered
- Being labelled as mentally ill may cause more distress
- People seen as mentally are often mistreated
