(2) Biomedical model, focus on diagnosis Flashcards
Guiding framework/model or paradigm are used to:
- Organize the available information about the onset and development of maladaptive behaviour
- Identify factors involved in psychological disorder and therapy
What is the explanation for the biomedical model?
Explanation: psychological symptoms caused by biological factors
What are the aims of the biomedical model?
identify the agent, or the mechanism
What is the treatment of the biomedical model?
medication, surgery, shock therapy
What did Kraepelin view abnormal behaviour as?
- View of disordered behaviour as due to organic causes (1856-1926)
- Emphasised the classification of abnormal behaviours into discrete disorders
- The view was of major importance in contributing to the emphasis of the medical approach to human problems
- Discrete disorders
- Certain symptom patterns occurred together regularly enough to be regarded as specific types of mental diseases
After the 70s what was behaviour viewed as?
Behaviour was then considered to be a function of an interaction of biological, psychological and social variables, abnormal behaviour was due to organic causes started decreasing
How does Schizophrenia develop?
heredity
How does depression develop?
chemical imbalances within the brain
How does anxiety develop?
defect within the autonomic nervous system
How does dementia develop?
impairments in structures of the brain
What are the risks of brain damage?
risk of psychopathology
What is Neural plasticity?
Flexibility of the brain in making changes in organization/function, existing neural circuits can be modified/new circuits can be generated
Who is at risk of brain defects?
Increased risk among the elderly due to age processing itself
What can cause disorders?
A disorder can be caused by either too much or too little of a particular neurotransmitter
How can hormonal imbalances effect brain disorders?
Hormones = chemical messengers secreted by a set of endocrine glands in our bodies
- Travel through our bloodstream affecting various parts of our body and brain
- CNS (central nervous system) linked to endocrine system
What is an example of a chromosomal abnormality?
Chromosomal abnormalities: down’s syndrome
what is physical deprivation associated with?
-Implicated in attention deficit disorder, depression, anxiety, eating disorders
What is a humans basic needs?
food, oxygen, water, sleep, elimination of waste
What are some examples of medical treatment?
- Brain stimulation therapies
- Surgery
- Pharmacological approaches
What is insulin shock?
- Introduced by Sakel in 1933
- Used mainly for schizophrenia in the 1940s and 1950s
- Involved inducing repeated comas via insulin injection over weeks or months
- Risks included obesity, seizures, brain damage or even death (mortality rate 1-5%)
- Initially thought effective, but randomised controlled trials found that this was not the case (Ackner et al., 1957)
- Fell out of use by the 1960s, to be replaced by medication
What is a Lobotomy?
- Prefrontal lobotomy was a common neurosurgical procedure: from 1935-55 over 40,000 were performed
- Involved severing the frontal lobes from the rest of the brain
- Developed by Egas Moniz who won the Nobel prize in 1949; later shot by former patient
- Popularised in the US by Walter Freeman
- Result: up to 4% death, inability to control impulses…
- Highly controversial
The story of Rosemary Kennedy
- Slow development
- Private home tuition, good family life lead to improvement
- At 21 became frustrated, violent, ran away
- Prefrontal lobotomy wiped out speech and personality
What -Brain stimulation therapies are currently used?
- Electroconvulsive therapy (ECT)
- Deep brain stimulation (DBS)
- Transcranial magnetic stimulation (TMS)
What surgery is currently used?
Surgery: Neurosurgery for mental disorder (NMD)
-Pharmacological approaches
What is electroconvulsive therapy (ECT)?
- Inducing seizures under general anaesthesia & with muscle relaxants
- Passing electrical currents (150 volt for one second) through a patient’s head
- Every neurotransmitter system is affected by ECT, but not entirely clear how it works
- Each year around 100 000 patients treated in USA
- Now used with patients who have not responded to other treatments. Very effective for acute treatment
- Relatively safe; side effects include: headache, muscle ache, nausea and temporary memory loss
- High relapse rate (e.g. Kellner et al., 2006)
What is Transcranial magnetic stimulation (TMS)?
- Used for treatment-resistant depression and anxiety
- Electromagnetic coil sends magnetic pulses through the patient’s scalp into the brain
- These affect the function of neural circuits involved in mood, though unclear how
- Pulses are more focused than ECT: can stimulate brain regions involved in mood
- Meta-analysis by Slotema et al. (2010): TMS is effective for acute depression
What is Deep brain stimulation (DBS)?
- Involves implanting electrodes in specific parts of the brain to deliver electrical stimulation
- Used for severe, treatment-resistant depression and OCD
- Currently only used experimentally, but seems effective (e.g. Mayberg et al., 2005)
- Patients reported a “lifting of the void” and “connectedness”
- BUT DBS requires brain surgery, so should be a last resort
What are Neurosurgery for mental disorder (NMD)?
- Involves destroying or ablating minute areas in the brain that might contribute to mental illness.
- Much more focused than prefrontal lobotomy/leucotomy
- Used very rarely for treatment-resistant depression and OCD
- Adverse effects: transient headaches, but no change in skill or personality
What are antipsychotics?
- Psychotropic medication – any medication capable of affecting the mind, emotions & behaviour
- Antipsychotics - reduce delusions and hallucinations by blocking dopamine receptors
- Used for schizophrenia, mania, Tourette’s syndrome, and psychotic episodes
- Introduced in 1955; powerful impact on quality of treatment and interaction with patients
- Persistent use / high dosage = side effects (e.g. involuntary twitching); new expensive types less side effects
- Not serious side effects, however there are some
What are Antidepressants ?
- Several types, acting on different neurochemicals
- Most common: tricyclics and selective serotonin reuptake inhibitors (SSRIs)
- Equally effective
- Extremely popular; on the increase
- Some side effects (nausia, insomnia, sexual problems)
- Used in other disorders such as bulimia, anxiety disorders, OCD, chronic pain…
What are Anti-anxiety (anxiolytics)?
- Sedative and muscle-relaxing properties, but highly addictive
- Patients become drowsy, lethargic
- Efficacy and side effects vary between individuals
What is Lithium?
- Used for the treatment of bipolar disorder
- Lightest of metals; inorganic salts; unknown mechanism
- Dosage crucial (toxic), and very individual (close monitoring)
- Very effective (70-80%) in Bipolar
- Also effective sometimes with unipolar depression
- Side effects: thirst, gastro problems, weight gain, tremor and fatigue
Advantages of Biomedical approach
- Suggests a clear mechanism for most disorders: discredited ‘possessions’ or supernatural explanations
- Has been particularly effective in delivering insights into disorders with a clear biological cause, e.g. Alzheimer’s
- Absolves patients of responsibility, guilt and blame for their condition, since there is an objective biological explanation
- Drug treatment has revolutionised patient care: it is generally effective and is faster than other therapies
- Treatment based on the scientific method: in theory this means treatments should only be adopted if proven effective
- Can be quick but doesn’t treat the cause
Example: antidepressants
- One recent meta-analysis suggested SSRI anti-depressants were no more effective than placebo, except in severe cases (Kirschal., 2008)
- But another showed that the picture is more complicated: patients are either responders or non-responders (Gueorguieva et al. 2011) Gueorguieva et al. (2011) analysed data from 7 trials (2515 patients)
- 76% responded to SSRI/SNRIs, but 24% did not
- Looking at the whole sample, the treatment efficacy would not have been clear.
What are some Limitations to the biomedical approach?
- Historically, some treatments were unsafe and ineffective Even now, most treatments have side effects
- We still do not know exactly how medications work
- Most importantly, are we treating the underlying cause, or just symptoms? Are drugs used as a ‘chemical straitjacket’ to subdue patients rather than cure them?
- Usage in children controversial, as interactions with brain development are still unknown
- Drug development depends on rigorous methods and the integrity of researchers and drug companies
Example: antipsychotics in childhood
- Controversial rise in paediatric bipolar diagnosis, mostly in US: 40-fold increase between 1994 and 2003 (Moreno et al., 2007)
- Treated with atypical antipsychotic drugs
- Administration Report: 500,000 children prescribed these in US
- These drugs also frequently used for ADHD and conduct disorder
- Use is controversial: side effects (drowsiness, nausea, weight gain, diabetes…) and unknown effects on developing brain
- Increased risk of sudden cardiac death (Ray et al., 2009)
What is the DSM?
- Summarizes all the diagnoses
- Specifies what must be present to make a given diagnosis
- Organises the diagnoses into a classification system
- Constantly revised
- There have been several revisions since it was first published in 1952; currently in its fifth edition DSM-5
- Gradually including more mental disorders
- Some have been removed and are no longer considered to be mental disorders, e.g. homosexuality
DSM 1 (1952) 132 pages:
Contained vague criteria heavily influenced by psychoanalytic theory & an attempt to standardize diagnostic practices in use among military personnel in WWII.
DSM 2 (1968) 119 pages:
included some new disorders but it was not much different from first edition
What did DSM 1 and 2 have in common?
Vague and unclear criteria for the diagnostic classification - Lack of homogeneity within categories, low reliability and validity, for instance: Beck et al. (1962) found that 4 experienced clinicians using DSM-I to diagnose 153 patients agreed on their diagnosis only 54% of the time
DSM 3 (1980) 494 pages:
Lists and describes over 200 specific diagnostic categories or disorders
-Increase in the specificity of criteria: e.g. specified for HOW long the person must show the symptoms of the disorder to be given the diagnosis
What was wrong with DSM 3?
- Clinicians agreed on their diagnosis only about 70% of the time (Kirk & Kutchins, 1992)
- The criteria were still vague and required clinicians to make inferences about the client’s symptoms
DSM 4 (1994):
Conservative approach: The reasons for changes in diagnosis would be explicitly stated and clearly supported by data
DSM 4 TR (2000) 943 pages:
Changes related to prevalence rates, course, and etiology Cultural and ethnic considerations included
Categorical approach:
Disorders are discrete –Are they really? What about comorbidity? Assumes that: All human behaviour can be divided into the categories of ‘healthy’ and ‘disordered’.
Dimensional approach:
Person’s behaviour is a product of deferring strengths and intensities of behaviour along several definable dimensions such as mood, emotional stability, etc.
DSM 5:
- The boundaries between many disorder categories are fluid over the life course – DSM-5 claims to be based on, or, at least is moving towards dimensional approach
- Symptoms assigned to one disorder may occur in many other disorders
- The client’s cultural and social context must be considered
- Making diagnoses requires clinical judgment, not just checking off the symptoms in the criteria
Diagnoses are made based on:
- The clinical interview
- DSM-5 text descriptions
- DSM-5 criteria
- Clinician judgment
- Need to take symptoms into account
Controversy over DSM 5
-Can lead to over-diagnosis and over-medication
Advantages of DSM
- Clarifies concepts
- Diagnosis have clinical utility - helps clinicians to determine prognosis and treatment plans
- Enables treatment – advantage for patient
- Enables research, etc
Disadvantages of DSM
- Overlap between disorders (comorbidity)
- Proliferation of disorders
- Human error
- Stigma associated with having a psychiatric diagnosis Etc.
- Stigma despite information being provided
- Stereotyping and labelling
International classification of diseases (ICD) – 10
- ICD-10 chapter V: Mental and behavioural disorders
- Part of the International Classification of Diseases
- Produced by the World Health Organization (WHO)
- Another commonly used guide (Europe and other parts of the world)
- DSM coding systems corresponds with the codes used in the ICD
- This not true always because the two publications are not revised synchronously
