Abnormal Psychology: Biological Aetiologies

Question 1

What is the Serotonin Hypothesis?

The hypothesis is supported by Caspi et al

Answer 1

• The Serotonin Hypothesis argues that a reduction in serotonin leads to an increased predisposition to depression
• Caspi’s study demonstrates a potential link between depression and serotonin

Question 2

Evaluate the Serotonin Hypothesis

The hypothesis is supported by Caspi et al

Answer 2

• reducing levels of serotonin in the brain doesn’t always lead to depression
• hypothesis is left with little support
• however, there’s plenty of evidence that SSRIs (selective serotonin reuptake inhibitor) increase communication from neurons that release serotonin, norepinephrine, and dopamine, and the consequences of transmission of neurochemicals can alleviate depression

Question 3

Evaluate genetic explanations of depression

Answer 3

Strengths:
- Twin studies have been highly reliable in their results
- Modern research has allowed us to actually locate genetic variations using very large sample sizes
- Modern research recognizes the interaction of environmental and biological factors and doesn’t use a solely reductionist approach

Limitations:
- Correlational studies do not establish a cause-and-effect relationship
- Twin studies have the problem of population validity - don’t necessarily represent the general population
- It’s impossible to isolate variables and separate out social factors in twin studies
- Genetic arguments don’t account for variations in symptomatology in cultures
- It’s not yet clear how genetic markers interact

Question 4

Evaluate the biochemical explanations of depression

Answer 4

Strengths:
- Several longitudinal case studies and animal research supports theories
- Practical applications of theories led to successful drug treatments that have improved some people’s lives

Limitations:
- Correlational research means that causation cannot be established and bi-directional ambiguity cannot be resolved
- The treatment etiology fallacy - the mistaken notion that the success of a given treatment reveals the cause of the disorder
- Biological explanations cannot explain the range of symptoms - May be cultural and cognitive factors too