3.1.1—Biological explanations

A biological explanation accounts for a psychological or health outcome through mechanisms such as genes, brain systems, hormones or neurotransmitters. It should specify how the mechanism could produce the observed change.

Biological evidence can be persuasive when converging methods agree, but reductionism may ignore cognition, learning and context. A biological association is not automatically a necessary or sufficient cause.

If a treatment changes serotonin signalling and symptoms change, the result supports a possible pathway but does not prove one neurotransmitter caused the disorder. Dose, placebo, adherence and side effects also matter.

‘Biological’ does not mean deterministic and ‘chemical imbalance’ is not a complete explanation. State the evidence, mechanism and alternative levels of analysis.