The psychological problems core studies: the classic study Caspi et al. (2003) on the 5-HTT gene and the influence of life stress on depression, and the contemporary study Tandoc et al. (2015) on Facebook use, envy and depression.

What this dot point is asking

OCR wants you to know the two psychological problems core studies. The classic study is Caspi et al. (2003), showing how the 5-HTT gene interacts with life stress to affect depression. The contemporary study is Tandoc et al. (2015), showing how Facebook use can lead to depression through envy. For each you need the aim, method, results, conclusions and an evaluation.

Caspi et al. (2003): the classic study

Aim

To find out whether a person's version of the 5-HTT gene affects how strongly life stress leads to depression, that is, whether the gene and the environment interact.

Method

A longitudinal study following a large group of people from New Zealand over many years (into their twenties). Researchers identified each person's 5-HTT alleles, classing them as two short, one short and one long, or two long. They also measured the number of stressful life events (such as job loss, relationship breakdown, illness) and whether the person showed depression.

Results

People with two short alleles were much more likely to become depressed when they had experienced many stressful events. With few stressful events, gene type made little difference. People with two long alleles were more resilient to stress.

Conclusion

Depression is best explained by a gene-environment interaction: a genetic vulnerability (short 5-HTT alleles) only leads to depression when combined with stress. This supports the idea, in depression explanations, that depression has both biological and environmental causes.

Tandoc et al. (2015): the contemporary study

Aim

To find out whether using Facebook is linked to depression in college students, and whether envy explains any link.

Method

A self-report survey (questionnaire) of around 700 college students in the USA. It measured their Facebook surveillance use (browsing and monitoring others' posts), feelings of envy, and symptoms of depression, then analysed how these related.

Results

Heavy Facebook surveillance use was not directly linked to depression. Instead, heavy surveillance use increased envy (from seeing others' holidays, possessions and happy events), and it was this envy that was linked to depression. Envy therefore mediated the relationship: Facebook led to depression only through the envy it produced.

Conclusion

It is not Facebook use itself but the envy it can trigger that is linked to depression, helping to explain the rising incidence of depression discussed in defining mental health.

Evaluating the two studies

Caspi et al. (2003) has the strengths of a longitudinal design, a large sample and objective genetic data, and it powerfully shows a gene-environment interaction. Its weaknesses are that it is correlational (it cannot fully prove cause), some later studies failed to replicate the gene effect, and measuring "life stress" relies partly on recall. Tandoc et al. (2015) has the strengths of a large, relevant sample and a clear finding about envy as a mediator. Its weaknesses are that it is correlational (envy is linked to depression, but depression could also cause more envious browsing), relies on self-report, and used only college students, so it may not generalise. Together they show depression has multiple causes (genes, stress and social comparison), reinforcing the need to treat the whole person.

Try this

Q1. Which gene did Caspi et al. (2003) study? [1 mark]

• Cue. The 5-HTT (serotonin transporter) gene.

Q2. According to Tandoc et al. (2015), what mediated the link between Facebook use and depression? [1 mark]

• Cue. Envy.

Q3. Give one weakness shared by both studies. [2 marks]

• Cue. Both are correlational (and rely partly on self-report), so they cannot fully prove cause and effect.