Drug Therapies for Schizophrenia

Give the name of one typical antipsychotic drug

Chlorpromazine

Give the name of two atypical antipsychotic drugs

• Clozapine

• Risperidone

Describe how typical antipsychotics work to reduce dopamine activity

1. Bind to dopamine receptors at receptor site without stimulating them

2. This blocks dopamine from binding to dopamine receptors

3. This reduces activation in the next neuron (Dopamine antagonists)

4. Reduces hallucinations

What did Thorney et al find to support the effectiveness of Chlopromazine?

Meta-analysis

• 13 trials

• Trials compared the effects of Chlorpromazine to controls taking placebo

Finding

• Chlorpromazine was more effective than placebo at:

  • Reducing symptom severity

  • Improving functioning of patient

  • Reducing relapse rate

In what way did drug treatments revolutionise treatments for psychotic patients?

1. Reduced severity of positive symptoms

2. This made patient more stable and improved their quality of life

3. This enabled deinstitutionalisation of many patients, allowing them to live in the community

Which type of symptoms do typical antipsychotics have little effect on? And why?

Negative symptoms

• Negative symptoms are generally associated with low dopamine activity in ventral striatum

• Typical antipsychotics decrease dopamine activity

What are the 4 main side effects of typical antipsychotics?

• Tardive Dyskinesia

• Sedation

• Blurred vision

• Tremors

Outline Tardive Dyskinesia

• Writhing movements in face and mouth

• Jerky limbs

What is meant by the chemical cosh argument?

• Idea that antipsychotic drugs don’t specifically treat the cause of schizophrenia

• Antipsychotics simply sedate patients, masking their symptoms

What is the problem with some placebo tests?

1. The drugs may appear affective, due to the placebo group having to come off symptom control medication

2. This makes placebo groups symptoms worse

Describe how clozapine works (an atypical antipsychotic)

1. Clozapine binds temporarily to the dopamine receptors → Reduces positive symptoms

2. Dissociates from dopamine receptors, so dopamine can still function

3. Blocks serotonin receptors → increases dopamine in some brain areas → Reduces negative symptoms

4. Acts on glutamate receptors (indirectly) → helps normalise glutamate activity → Reduces negative symptoms

Describe how Risperidone works (an atypical antipsychotic)

1. Risperidone binds temporarily to the dopamine receptors → Reduces positive symptoms

2. Binds more strongly to dopamine receptors than Clozapine (so lower doeses can be given)

3. Blocks serotonin receptors → increases dopamine in some brain areas → Reduces negative symptoms

What are the 3 key strengths of atypical antipsychotics compared to typical antipsychotics ?

• Effective in 85% of patients (compared to 65% in typical)

• Better effect at reducing negative symptoms than typical antipsychotics

• Less side effects (especially Parkinson’s type symptoms) than typical antipsychotics (Counter: Tardive Dyskinesia is still a problem)

What is the main problem with Clozapine?

Serious side effects

• 1-2 % of patients develop agranulocytosis (a fatal white blood cell disorder) with Clozapine

What are the 3 main side effects of atypical antipsychotics?

• Sedation

• Confusion

• Weight gain (may lead patients to stop taking medication)

Outline the aims of the 3rd Generation of drug treatment for Schizophrenia

• Over 76 drugs in various phases of development → Each target a very specific set of receptor sites

• Aim to be more effective in treating Schizophrenia and have less side effects

What are the 3 main positive evaluation points for drug treatments?

• More effective than any other kind of treatment for Schizophrenia → Suggests Schizophrenia has strong biological cause

• Works quicker than other psychological therapies

• Reduces symptoms, allowing patients to live relatively normal lives

What are the 3 main negative evaluation points for drug treatments?

• Most effective when used alongside other forms of therapy (e.g: family therapy or CBT) → Supports interactionist explanation of Schizophrenia

• Not a cure → If patient comes off drug treatment symptoms will be worse than before → More dopamine receptors produced on synaptic membrane

• The Chemical Cosh argument → Does the treatment actually work?