Psychological Problems Studies

• If one monozygotic twin became depressed there was a 46% chance that their co twin would become depressed.
• If one dizygotic twin became depressed there was a 20% chance that their co twin would become depressed.
• This shows that depression may be genetic.

It may be that some people have a genetic predisposition to become depressed because they have a gene that increases their risk but they only go on to become depressed because they are in a stressful situation that triggers the genes that effect their mood. This combined explaination is often reffered to as the diathesis-stress model.

• There is lots of research evidence to support the idea that some people are more prone to depression than others for example Caspoi et al (2003) found that people with a variation o the serotonin transporter gene were more likely to react negatively to stressful life events and develop depression.
• If genes can explain depression then this may take away the stigma of being diognosed with depression.

• Gene theory is deterministic as it assumes that if you have certain genes you are more likely to become depressed.
• Gene theory is reductionist in failing to take into account other factors that can explain why someone may develop depression and not just genes.

• Research has shown that stressful life events cause depression but not everyone who experiences stressful life events becomes depressed.
• Tihs study looks at whether a gene linked to the neurotransmitter serotonin (a chemical known to be involved in depression) makes some people more likely to become depressed after stressful life events than others.

• To investigate why stressful life events lead to depression in some people and not others.
• To investigate whether stressful life events were more likely to lead to depression in people with a certain variation of the 5HTT gene (a gene linked to the amount of serotonin available in the brain).

• The study had 847 participants in total and they were in three groups:
  • Group 1 - two copies of the short version of the gene (17% of the participants).
  • Group 2 - one copy of the short version and one copy of the long version of the gene (51% of the participants).
  • Group 3 - two copies of the long version of the gene (31% of the participants).

• Each participant completed a questionnaire that measured life events that had occurred between their 21st and 26th birthdays.
• Each participant than completed another questionnaire to assess if they had any other symptoms of depression after in the year before their 26th birthday.
• The researchers thus had quantitive data in the form of a depression score.

• Participants found to have at least one short version of the 5HTT gene and who had been through stressful life events between the age of 21 and 26 years old showed a significant increase in symptoms of depression after the event and up until they were 26 years old.
• Participants with a short version of the 5HTT gene and who had experienced stressful life events were more likely to be diognosed with depression than participant with two long version of the gene.

• Those with a short version of the gene were more likely to develop suicidal thoughts after stressful life events than those with two long versions of the gene.
• Those with two short versions of the gene were most likely to report severe depressive symptoms if they had suffered a number of stressful life events, including a significantly higher report of suicidal thoughts if they had faced more than three stressful life events.

• There is an interaction between life events and genetic influences in causing depression. This suggests that both nature and nuture work together to increase the likelihood of developing depression.

• There was a large sample size of 847 participants and so generalising the results from the study is easier than if the sample were smaller.
• The study could be useful to doctors as it tells them that someone with depression could have different causes for their symptoms. This may them to understand why some people become depressed after a life situation while others don't.

• Evidence from the questionnaires is self-reported data which may not be reliable as participants may show social desirability bias.
• The researchers thought that some people might be more likely to put them in situations where stressful events might happen. the short version of the 5HTT gene might be a natural factor that makes people prone to situations that are stressful. Therefore instead the personn is in more stressful situations that could cause depression

• According to Beck depression can be explained by negative thought patterns. He called these cognitive Biases.
• Beck thought that this negative way of thinking was probably developed from bad experiences in the past. This means that people develop a negative self schema when all information is perceived in a negative way.

• Overgeneralisation - Drawing sweeping conclusions based on a single incident.
• Magnification - Seeing problems as far worse than they are.
• Selective Perception - Focusing on negative details or events whilst ignoring positive ones.
• Absolutist thinking - Seeing everything in terms of success or failure.

• Ellis's ABC Model:
• A - Activating event or Trigger
• B - Belief
• C - Consequence (feelings, behaviours, thoughts & symptoms)