Dopamine pathways

Mesolimbic

• Overactive in schizophrenia due to too much dopamine
• Causes positive symptoms

Mesocortical

• Underactive in schizophrenia due to reduced dopamine
• Causes negative symptoms

Tuberoinfundibular

• Affected by antipsychotics → (increased PRL) galactorrhoea, gynaecomastia, amenorrhoea and sexual dysfunction

Nigrostriatal

• Affected by antipsychotics → extra-pyramidal side effects

Other receptors

• Alpha - blocking results in orthostatic hypotension
• Cholinergic - blocking results in dry mouth, blurred vision, urinary retention, constipation (anti-cholinergic side effects)
• H1 receptors - blocking causes sedation and weight gain