Biological explanations and treatments for schizophrenia

Genetic explanation for schizophrenia

No one gene is thought to be responsible for this disorder - it's more likely that different combinations of genes make individuals more vulnerable to schizophrenia. Having these genes does not necessarily mean an individual will develop schizophrenia.

Gottesman and shield's twin study

concordance rate of 42% for MZ and 9% for DZ.

Gottesman 2010 - participants

75,000 in Denmark

Gottesman results

The risk of being diagnosed with schizophrenia was much greater for offspring of two parents with a diagnosis (schizophrenia/ bipolar) - 27.3%. The risk increased when the calculation included offspring being diagnosed with other mental health issues - 67.5%. For offspring who had neither parent having any diagnosis, the risk was 1.1%

Why are adoption studies useful?

Because of the difficulties of disentangling genetic and environmental influences for individuals who share genes and environment, studies of genetically related individuals who have been reared apart are used.

Tienari et al

of the 164 adoptees whose biological mothers had been diagnosed with schizophrenia, 6.7% also received a diagnosis of schizophrenia, compared to just 2% of the 197 controls adoptees (those born to non-schizophrenic mothers).

Supporting research for genetic explanation

Overwhelming - genetic factors make some people much more vulnerable to developing disorder compared to others. Gottesman and shields, Gottesman and tienari.

Applications of genetic explanation/determinism

Understanding genetic vulnerabilities enable researchers to make predictions of mental illness. This deterministic view can help to direct early interventions, support, or treatment.

Alternative explanation to genetic (nature nurture)

There are a number of factors in the environment associated with risk of the disorder (which could account for concordance rates of less than 100%) and other research on expressed emotion has shown that the negative emotional climate in some families may lead to stress beyond an individual's coping mechanisms, thus triggering a schizophrenic episode.

Issues with supporting research for genetic explanation

Cause and effect may be difficult to establish with twin, family and adoption studies due to a lack of control, it is difficult to suggest that genetics is the only cause of schizophrenia. Use the Gottesman research for this point.

What is the Broca's area responsible for?

Speech production

The dopamine hypothesis- Broca's area

Excessive levels of dopamine could be linked to speech poverty ad auditory hallucinations

Where is the Broca's area?

Bottom front of brain

Where is the prefrontal cortex located?

Right at the front of the frontal lobe

What is the prefrontal cortex responsible for?

Planning complex behaviour and decision making

Low dopamine effect on prefrontal cortex

Avolition, as difficult to initiate goal-directed behaviour

What are neural correlates?

patterns of activity in the brain that occur with a schizophrenic experience. As they occur simultaneously, this could lead us to believe that the patterns observed are implicated in causing schizophrenia.

What part of the brain contains the auditory cortex?

Superior temporal gurus

What is the superior temporal gyrus responsible for?

Processing sounds

What does ACC stand for?

anterior cingulate cortex

What is the anterior cingulate cortex implicated in?

Empathy, impulse control, emotion, and decision making

According to a scanning study of patients with auditory hallucinations, what was found about the Anterior cingulate cortex and superior temporal gyrus?

They were both negatively correlated with neural activation levels - lower neural activation levels were found in superior temporal gyrus and anterior cingulate gyrus and were correlated with an increase in positive symptoms such as auditory hallucinations.

What part of the brain is responsible for the anticipation of rewards?

Ventral striatum

A correlation was found between activity levels in the ventral striatum and severity of avolition.

Negative

As neural activity _in the Ventral striatum, avolition symptoms increases.

Decreases

Supporting research for the dopamine explanation

Allen et al (2007) scanned patients with auditory hallucinations, compared to a control. A negative correlation was found - lower neural activation levels were found in superior temporal gyrus and anterior cingulate gyrus and were correlated with an increase in positive symptoms such as auditory hallucinations.

Useful applications of the dopamine explanation

anti-psychotic drugs reduce the effects of dopamine and so reduce the symptoms of schizophrenia. Therefore, this explanation is useful in helping to develop treatments for schizophrenia.

Positive of dopamine hypothesis being reductionist

simplistic explanation that is easy to explain to patients

Negative of dopamine hypothesis being reductionist

Schizophrenia is a complex disorder with multiple neurotransmitter systems implicated. The dopamine hypothesis might oversimplify the intricate neural mechanisms involved in the disorder. Limits understanding

Inconsistencies in dopamine levels

Not all studies consistently find elevated dopamine levels in individuals with schizophrenia. This inconsistency raises questions reliably of dopamine dis regulation as the sole explanation. In Allen study, not everyone fit correlation

Dopamine explanation is deterministic- benefit

Not patients fault, provides relief

Name of biological treatment for schizophrenia

Anti-psychotics

Anti-psychotics are usually recommended as for symptoms of schizophrenia, after which clinicians use a combo of____

The initial treatment, medication and psychological therapies.

How do all anti-psychotics work?

Reduce dopaminergic transmission therefore reduce action of dopamine in areas associated with schizophrenic symptoms.

What are the two types of anti-psychotics?

typical and atypical

Example of typical antipsychotic

chlorpromazine

example of antipsychotics

Clozapine

What do typical antipsychotics combat? Such as? What don't they combat well?

Positive symptoms such as hallucinations and thought disturbances, but doesn't work well with negative symptoms

What do atypical antipsychotics combat?

Positive symptoms, and also have beneficial effects on negative symptoms.

Typical antipsychotics block the which reduces the chances of being

Post synaptic dopamine receptors, dopamine, received

When the dopamine is received less, the effect of the dopamine is reduced. How is this important to schizophrenics?

Schizophrenics ca have too much dopamine or too many dopamine receptors. Reducing transmission can deduce positive symptoms like hallucinations and has a calming effect.

Typical antipsychotics has a ____ frequency of side effects

High

Examples of COMMON side effects for typical antipsychotics

dizziness
drowsiness
anxiety
sleep problems (insomnia)
breast swelling or discharge
changes in menstrual periods
weight gain
swelling in hands or feet
blurred vision
constipation
impotence or trouble having an orgasm

Serious long term side effects of typical anti psychotics

Movement disorder - extra-pyramidal side effects, where you can't control your motor movements eg restlessness and uncontrollable facial movements

Over blocking of dopamine in the hypothalamus can lead to a delirium, coma and even death! Some individuals died of this in the 1960's when the drugs were first introduced.

How are patients monitored when taking typical antipsychotics?

Regular blood tests

How do atypical anti psychotics work?

They block both dopamine and serotonin receptors

Atypical drugs only partially block the…

Post synaptic dopamine receptors

Why do atypical antipsychotics only partially block the dopamine receptors?

instead of cutting off dopamine on a large scale (like typical anti-psychotics), it still allows for some of the dopamine to be received.

Purpose of blocking serotonin receptors

Serotonin is believed to help stabilize mood and have a calming effect. This is another reason why it is thought to improve negative symptoms more so than the Typical anti-psychotics. It is also believed that people with schizophrenia, may have higher levels of serotonin, so reducing the amount they are received may help to bring serotonin down to a normal level.

Common side effects of atypical antipsychotics

blurred vision
confusion
dizziness
irregular heart beat
fever
sleepiness or unusual drowsiness
sweating
trembling or shaking of the hands or feet

Rare side effects of atypical antipsychotics

convulsions
problems in urination
hyperventilation
loss of interest, pleasure or appetite
muscle spasm or jerking of the arms or legs
sudden loss of consciousness
decreased sexual ability

Research to support the biological approach to schizophrenia - treatments

Thorney et al - reviewed studies on the drug treatments of schizophrenics by comparing groups who were taking Chlorpromazine to groups who were taking a placebo drug. Chlorpromazine was associated with better overall functioning, reduced symptom severity and fewer relapses in comparison to the placebo.

Usefulness of drugs study - difference in side effects

Crossley - meta analysis for 15 studies to examine side effects and efficacy of atypical vs typical in early phase of treatment - Patients on atypical anti-psychotics gained more weight than those on typicals, whereas those on typicals experienced more extrapyramidal side effects. This could highlight the usefulness in terms of which drugs are more ethical. The usefulness of drug treatments should consider side effects, as if one form of drug has an increased risk in creating more problems in the individual than what they started with, this drug can be classed as more effective as a treatment

Usefulness of drugs - weakness

half of the patients taking typical anti-psychotics experience Parkison's or extrapyramidal problems. These side effects can be so distressing for the patient that other drugs have to be given to control them, or the patient may stop taking their anti-psychotic medication.

Alternative explanation - better treatment

Drug treatments are shown to be less beneficial when taken as a sole treatment. Tarrier et al. (2000) focused on people with schizophrenia receiving 20 sessions of CBT in 10 weeks. Those who participated in CBT and drugs had a better reduction in symptoms compared to those who were just taking drugs.

Lack of free will in drugs

Patients feel out of control, reduces motivation to look for solutions to alleviate these stressors. Takes away free will, could encourage cycle where individuals stop and start medication.