# Biological treatment (depression)

> IB Psychology · IB Psychology 2027 First Assessment
> Source: https://www.owlsprep.com/study/ib-psychology-hwb-biological-treatment-depression/

The explanation and effectiveness of one or more biological treatments of one or more mental health disorders.

## Learning objectives

- The explanation and effectiveness of one or more biological treatments of one or more mental health disorders.

## How often is this tested?

Based on OwlsPrep's analysis of official CIE IB_PSYCH P2 past papers (2019–2025): **Biological treatment (depression)** appears **13 times** in the last 7 years — **4.5%** of all P2 questions (13 of 288).

Most-tested forms: Essay: Discuss (22 marks) (11), Essay: Contrast (22 marks) (2).

## Core concept

Biological treatments target the physical basis of a disorder. For depression the main example is antidepressant drugs such as SSRIs (e.g. fluoxetine), which increase serotonin availability at the synapse by blocking its reuptake, aiming to lift mood. They are judged on effectiveness — how far they reduce symptoms compared with a placebo or other treatments, and at what cost in side effects and relapse. Evidence shows they help many patients, but often work best combined with psychological therapy rather than alone.

## Key studies

IB Psychology answers must be supported by named studies. Learn these to cite as evidence:

**TADS (2007)** — In the Treatment for Adolescents with Depression Study, fluoxetine, CBT, and their combination were all effective, with the combination giving the fastest short-term response. — *Controlled effectiveness evidence for a biological treatment (fluoxetine) — and evidence that the drug alone is not the whole answer.*

## Evaluation (AO3)

**Strength — clear target and trial evidence** — Drug action gives a testable causal target (serotonin reuptake), and randomised trials such as TADS provide effectiveness evidence at scale.

**Limitation — symptoms not causes, and ethics** — Drugs treat symptoms rather than causes, carry side effects and relapse risk, and TADS shows combination therapy outperformed medication alone — raising responsibility questions about medicating (especially adolescents).

## Scope

> **note**
>
> This card is the biological treatment of a disorder and its effectiveness. The psychological treatment of the same disorder is HWB_10; prevention/treatment of non-disorder health problems is HWB_9; the drug's mechanism sits in BIO_9.

## Common pitfalls

- **Wrong:** Describing how an antidepressant works (its mechanism) but not evaluating its effectiveness — or claiming drugs 'cure' depression.
  - Why it fails: A frequently penalised misconception in IB Psychology exams.
  - Correct: The KP asks for explanation AND effectiveness: weigh symptom reduction versus placebo, side effects, relapse, and the TADS finding that combination beat medication alone. Drugs manage the disorder, they do not simply cure it.

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