Biological Therapies

• administration of typical antipsychotics

  orally (tablets) or syrup and can be administered via injection if high risk of non-compliance
• examples of typical antipsychotics

  • chlopromazine
  • acts on positive symptoms
• mechanism of typical antipsychotics

  • dopamine released from vesicles then from presynpatic membrane
  • antipsychotic binds with but does not stimulate D2 receptors; some dopamine binds with postsynaptic receptors
  • excitatory effect on postsynaptic cell-fires
  • overall effect is normal or reduced dopamine but other pathways blocked too
  • block dopamine from going to the next cell
  • treats the positive symptoms
• administration of atypical antipsychotics

  orally (tablets) or syrup, can be injected via injection if high risk of non-compliance
• examples of atypical antipsychotics

  • olanzapine
  • clozapine
• mechanism of atypical antipsychotics

  • antipsychotic binds with but does not stimulate receptors, also rapidly dissociates
  • some dopamine binds with receptors
  • overall effect is normalised dopamine and serotonin transmission, with milder side effects
  • increase serotonin levels by blocking its reuptake so it goes to the next cell
  • reduces dopamine (positive symptoms) increases serotonin (negative symptoms)
• evidence for effectiveness

  • Leucht et al (2012) - meta-analysis involving over 6000 patients
  • placebo - 64% relapse
  • antipsychotics - 27% relapse
  • however, figures are misleading as 36% of patients benefited from the placebo
• appropriateness

  • dizziness, agitations, sleepiness, stiff jaw, weight gain and itchy skins
  • can result in tardive dyskinesia, which is caused by dopamine supersensitivity and manifest as involuntary facial movements such as grimacing, blinking and lip smacking
  • most serious side effect is neuroleptic syndrome which can be caused as the drug blocks dopamine action in the hypothalamus