3.1.8—Biological treatment
- Syllabus
- First assessment 2027
- Objective
- 3.1.8
- Level
- HL
Biological treatments target a mechanism but also carry trade-offs
A biological treatment changes a bodily process—through medication, surgery or another physiological intervention—to reduce symptoms or risk. Its rationale should specify the target, expected pathway and time course.
Evidence needs an appropriate comparison, clinically meaningful outcome and attention to adherence, placebo effects, side effects and relapse. A statistical difference does not guarantee that benefits outweigh harms for every patient.
An antidepressant may alter neurotransmission and reduce symptoms for some patients, while delayed onset or adverse effects affect adherence. Combining medication with psychological or social support may address mechanisms the drug cannot.
A biological treatment is not automatically more objective or curative. A plausible mechanism is only one part of the evidence and does not erase informed choice.