Biological therapies for schizophrenia

Biological therapies for schizophrenia

Drug therapy

Typical (old) antipsychotics

·       Chlorpromazine

·       Dopamine antagonists- reduce dopamine

·       Block dopamine receptors in the synapses in the brain

Atypical (new) antipsychotics

·       Clozapine

·       Works in the same qay but binds to serotonin and glutamine receptors

·       Risperidone

·       Same and above but binds more strongly to dopamine receptors

Drug therapy is most common for treating schizophrenia

Drugs are called antipsychotics

Tablets, syrup or injection every 2-4 weeks

Chlorpromazine:

·       First type of antipsychotic

·       Reduce the action of a neurotransmitter. Block dopamine receptors in the synapses of the brain, reducing the action of dopamine.

·       Dopamine levels initially build but then its production is reduced. Normalises neurotransmission in key areas of the brain, reducing symptoms like hallucination

·       Has an effect on histamine receptors but not understood how it leads to sedation

·       Used to calm down patients

Clozapine:

·       Developed in the 60s

·       Binds to dopamine receptors in the synapse but also acts on serotonin and glutamate receptors

·       Improves mood and reduces depression and anxiety but also improves cognitive functioning

·       Prescribed to those at risk of suicide

Risperidone:

·       Developed in the 90s

·       Developed to try and create a drug as effective as clozapine but without side effects

·       binds to dopamine and serotonin receptors but binds more strongly to dopamine than clozapine does which is why its more effective in smaller doses

Evaluation:

Evidence for effectiveness:

·       Thornley et al- reviewed studies comparing the effects of chlorpromazine to control conditions where ppts received a placebo. Results from 13 trials with 1121 ppts showed that chlorpromazine was associated with better overall functioning and reduced symptom severity.

·       Meltzer- concluded that clozapine is more effective than typical antipsychotics and other atypical antipsychotics and that is effective in 30-50% of treatment resistant cases.

Serious side effects:

·       Typical antipsychotics are associated with side effects including.

, dizziness, agitation, sleepiness, stiff jaw, weight gain etc

·       Long term use can lead to tardive dyskinesia which is involuntary facial movements e.g. grimacing, blinking cased by dopamine super sensitivity

·       Mose serious side effect is neuroleptic malignant syndrome, high temperature, coma and can be fatal. It is believed to be caused by blocking dopamine action in the hypothalamus.

Use of antipsychotics depends on the dopamine hypothesis:

·       The original dopamine hypothesis suggests that high levels of dopamine activity causes schizophrenia

·       However the later hypothesis suggests that there are low levels of dopamine activity in other areas of the brain

·       Some people don’t believe antipsychotics work and it is not clear

Problems with the evidence for effectiveness

·       Healy- suggested that some successful trial have had their evidence published multiple times, exaggerating the evidence for positive effects

·       He also says that because antipsychotics have calming effects it is easy to demonstrate positive effects, this is not the same as saying they reduce the severity if psychotic symptoms

·       Says studies assess the short term n=benefits rather than long term benefits and compare patients who keep taking antipsychotics with those suffering withdrawal just stopped taking them

The chemical cosh argument

·       Widely believed that antipsychotics are used for the benefit of the medical staff rather than patients

·       The drugs make patients easier to work with

·       Although short term use for calming patients is recommended this practice I seen by some as human right abuse