Biological therapies for SZ: Drug Therapy Flashcards
(8 cards)
what drug therapy is used most commonly
Antipsychotic drugs
types of Antipsychotic drugs
Typical antipsychotic drugs
- Chlorpromazine
Atypical antipsychotic drugs
- Clozapine
Typical antipsychotics
Positive symptoms (eg. delusions, hallucinations) thought to byproducts of an overactive dopamine system
‘Typical’ antipsychotic drugs (eg chlorpromazine) are dopamine antagonists that work directly on reducing the effects of dopamine.
Bind to all dopamine receptors (D2 receptors) but not stimulating them, thus blocking their action.
Reduces effects of dopamine -> reduces dopamine’s influence on thought, emotion and behaviour -> reduced positive symptoms
Hallucinations and delusions usually diminish within a few days of beginning medication
But other symptoms may take several weeks before significant improvement.
Typical antipsychotics symptoms
• block all D2 receptors -> upset muscle control
• block acetylcholine receptors -> sedation/confusion, reduce learning
• block noradrenaline -> upsets blood pressure, dizzy
• block some serotonin -> affect appetite, weight gain
Atypical antipsychotics
More recently, ‘atypical’ antipsychotic drugs (eg. Clozapine) have been developed
Aim to more effectively treating both the positive/ negative SZ symptoms
Unlike typical APs, they temporarily block some dopamine receptors before dissociating to allow normal dopamine transmission.
Major impact on serotonin receptors (increase/descrease transmission) -> mood regulation -> decrease negative symptoms
‘Second-generation’ APs - claim to be different to ‘typical’ APs in 3 main ways:
• lower risk of extreme side effects
• beneficial effect of negative symptoms (as well as positive)
• suitable for treatment-resistant patients
Take longer to work than typical APs
Differences between typical and atypical APs
- T: block all D2 receptors, AT: temporarily block some D2 receptors
- T: treat positive symptoms, AT: treat positive/negative symptoms
- T: Higher risk of extreme side effects, AT: lower risk of extreme side effects
- T: minimal effect on seratonin transmission, AT: major impact on seratonin system (increase/decrease transmission)
Evaluate drug therapy for SZ:
STRENGTHS
TYPICAL
P) support for effectiveness of Chlorpromazine (typical AP) from placebo research: Thornley et al (2003)
E) compared effects of Chlorpromazine to control gcs who received placebo.
E) Chlorpromazine associated w reduced symptom severity/ reduces relapse rates.
L) typical APs are medically effective at preventing relapse
ATYPICAL
P) support for effectiveness of atypical APs: **Meltzer (2012) **
E) Clozapine is more effective than typical antipsychotics (effective in 30-50% of treatment-resistant cases where typical antipsychotics failed
L) Atypical APs more effective than typical APs & more appropriate for treatment-resistant patients
E) BUT, Leucht at al: meta analysis - two new drugs only ‘slightly’ more effective, other two new drugs were no more effective -> very little difference in the effectiveness of atypical compared to typical
P) atypical APs: rates of tardive dyskinesia much lower
E) Jeste et al: 5%
E) more appropriate than conventional antipsychotics as they have fewer side effects
L) patients more likely to continue their medication and see more benefits
Evaluate drug therapy for SZ:
LIMITATIONS
TYPICAL
P) typical APs = less appropriate due to worrying side effects.
E) 30% develop ‘tardive dyskinesia’
E) suffer uncontrollable, repetitive movements eg lip smacking, excessive blinking
L) inappropriate if costs of taking the drug outweigh the benefits
BOTH
P) inappropriate: side effects -> problems with patient compliance
E) 50% stop medication after a year, and 75% after two years.
E) “Revolving Door Syndrome” - patient reluctant to take their medication -> regularly relapses -> admitted for care -> treated successfully with drugs again -> avoid taking them when released
L) inappropriate as rarely lead to a long-term and stable recovery
