Dopamine hypothesis

Dopamine hypothesis

Hyperdopaminergia: excess DA in D2 receptors in subcortex, positive symptoms

Hypodopaminergia: too little DA in D1 receptors in frontal cortex, negative symptoms

Prefrontal cortex

Responsible for thinking and decision making

Practical application of drug treatments from Leucht meta analysis

Leucht meta analysis found all antipsychotics tested were significantly more effective than a placebo in treatment of both positive and negative symptoms

If medicine targeting DA is effective, suggests DA is involved in SZ

Reductionism

Both glutamate and increased serotonin are also found to be involved in in SZ

DA hypothesis not comprehensive enough in explaining SZ, other biological factors also need to be considered alongside psychological factors to develop a full understanding of cause of SZ

Cause and effect

We can’t ethically manipulate DA levels in people, so research into DA hypothesis can only measure DA levels after SZ is developed, so DA imbalance might be a symptom of SZ rather than cause

No confident conclusion that DA causes SZ, so be cautious