Inherited Traits: Research suggests that a predisposition for depression can be passed down through genes, influencing how the brain processes chemicals.
The MAOA Gene: Sometimes referred to as a 'dysfunctional gene,' variants of the Monoamine Oxidase A gene can disrupt serotonin levels, potentially leading to symptoms like irritability or hostility.
Nature vs. Nurture: While environmental factors (nurture) play a role, the biological theory argues that the underlying vulnerability is often a result of one's genetic makeup (nature).
Mechanism of Action: Selective Serotonin Reuptake Inhibitors (SSRIs) work by blocking the reuptake pumps on the presynaptic neuron.
Increased Availability: By preventing reuptake, SSRIs ensure that more serotonin stays in the synaptic cleft for a longer duration, increasing the likelihood of binding to postsynaptic receptors.
Therapeutic Goal: The objective is to 're-balance' brain chemistry, which is hypothesized to restore a more stable and positive mood in the patient.
| Feature | Biological Theory | Psychological Theory |
|---|---|---|
| Primary Cause | Physical/Chemical imbalance | Cognitive patterns/Environment |
| Focus | Neurotransmitters & Genetics | Thoughts, feelings, & experiences |
| Treatment | Drug therapy (e.g., SSRIs) | Talk therapy (e.g., CBT) |
| View of Patient | Passive recipient of biological traits | Active participant in changing thought patterns |
Link Action to Behavior: When discussing serotonin, always explicitly connect its chemical action (e.g., low levels) to the resulting behavior (e.g., depressive symptoms like low mood or sleep disruption).
Define Key Terms: Ensure you can clearly define 'reuptake,' 'synaptic cleft,' and 'neurotransmitter' as these are foundational to the biological explanation.
Evaluate Both Sides: Be prepared to discuss both the strengths (e.g., development of effective medication) and the weaknesses (e.g., the theory is reductionist) of the biological approach.
Check for Nuance: Remember that 'behavior' in depression covers a wide range of symptoms, including physical ones like sleep and temperature regulation, not just emotional sadness.
The 'Single Cause' Fallacy: A common mistake is assuming serotonin is the only factor; modern science recognizes that depression is multifaceted and likely involves many biological and environmental variables.
Instant Results: Students often mistakenly believe antidepressants work immediately. In reality, while they change chemistry quickly, the clinical improvement in mood often takes weeks.
Reductionism: Critics argue that reducing a complex human experience like depression to a simple chemical mechanism ignores the importance of a person's life history and social context.
