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IB DP Psychology — Biological Approach | SL & HL | Paper 2 (Health & Well-Being Option)
🎯 Learning Intentions By the end of this note, you will be able to:
- Define psychopharmacology, antidepressants, antipsychotics, and anxiolytics using IB-aligned terminology.
- Explain how drug treatments work at the neurochemical level, including the role of neurotransmitters such as serotonin and dopamine.
- Describe the mechanism of action of SSRIs, antipsychotics, and benzodiazepines in treating mental health disorders.
- Evaluate research evidence for biological treatments using supporting and opposing studies in ACAS format.
- Apply biological treatment concepts to a real-world case study from the biological perspective.
- Discuss the ethical implications and limitations of biological treatments for mental health disorders.
- Analyse biological treatments using relevant concept areas: Causality, Bias, Responsibility, Perspective, and Change.
Introduction & Context
Imagine waking up every morning with a weight so heavy that getting out of bed feels impossible — not because of laziness, but because your brain's chemistry is working against you. For millions of people around the world, this is the daily reality of living with a mental health disorder such as depression, schizophrenia, or an anxiety disorder. The question that has driven psychiatry for decades is deceptively simple: if the brain is a biological organ, can we treat its disorders the same way we treat a broken bone or an infection — by targeting the physical cause directly?
This question sits at the heart of the biological approach to mental health. The approach assumes that psychological disorders have identifiable biological underpinnings — imbalances in neurotransmitter systems, structural brain abnormalities, or genetic vulnerabilities — and that correcting these biological factors should alleviate psychological symptoms. Biological treatments, most commonly in the form of psychiatric medication, are today the most widely prescribed interventions for mental health disorders globally. Understanding how they work, what the evidence says, and what their limitations are is essential for any psychologist evaluating the treatment of mental illness.
🔧 Analogy — The Faulty Thermostat Think of the brain's neurotransmitter systems as a thermostat regulating the temperature of a house. In a healthy brain, the thermostat keeps the emotional "temperature" stable. In depression, the thermostat is set too low — the house is cold and the heating system (serotonin) isn't working efficiently. Biological treatments like SSRIs are like a technician adjusting the thermostat mechanism so that the heating system functions properly again. The analogy also reveals a limitation: fixing the thermostat doesn't address why it broke in the first place, and it doesn't teach the house's occupants how to cope with cold weather on their own.
Core Concepts
Before exploring specific drug classes, it is important to understand the foundational logic that makes biological treatment possible. The brain communicates through chemical messengers called neurotransmitters. These molecules are released from one neuron, cross a tiny gap called the synapse, and bind to receptors on the next neuron. Different neurotransmitter systems regulate different aspects of mood, cognition, and behaviour. When these systems malfunction — whether due to genetics, stress, or other biological factors — the result can be the symptoms we recognise as mental health disorders.
Psychopharmacology is the scientific discipline that studies how drugs affect the brain and behaviour. Psychiatric medications work by altering neurotransmitter activity — either increasing or decreasing the availability of specific chemicals at the synapse. This is not a blunt instrument: modern