Causes of Depression

Twin studies if depression was a genetic disorder we would expect to see high concordance rates between twins with depression, McGuffin (1996) found that there was a 46% concordance rate between MZ twins and 20% between DZ twins- therefore depression has a substantial heritable component

Family studies the closer you are to someone in your family who has depression the more likely you are to get depression yourself, Gershon (1990) found that rates of depression in individuals with a first degree relative who had depression was two-three times higher than that of the general population (which is 5%)

However... both family studies and twins studies don't show concordance rates of 100% therefore genetics is not the sole cause of depression- it also ignores environmental and social factors amongst families which would be similar due to being raised in the same place  

Adoption studies are a way of dealing with the social issues in genetic studies, Wender (1986) found that found that biological relatives of adopted sufferers of depression were seven times more likely to suffer compared to the adoptive relatives 

Serotonin has been linked to depression, it is thought that when a person has low levels of serotonin (which is a 'feel good' neurotransmitter) they are more likely to get depression- the anti-depressant drug's success, prozac, confirms this relationship

Delgado et al (1990) put his patients on a special diet that lowered their serotonin levels, found that patients stared to get symptoms of depression again

How ethical is this study?

Freud (1917) explains depression through childhood experiences, his theory states that depression is caused over the loss of something e.g a job or a loved one- this grief feeling is then directed back at yourself which is why depressed patients have feelings of worthlessness. He also said that it makes you relive past experiences where you have suffered from loss which is why one can be susceptible to depression for their whole life 

Supporting evidence includes Shah and Waller (2000) who found that many people with depression describe their parents as affetionless- supporting Freud's theory

However... this may not be very reliable because memories can be false and there may be demand characterstics/social desirability bias 

This theory is not falsifiable and therefore can't be tested scientifically- it also ignores any biological explanations and explains that it runs in families purely because of environmental factors

Involves negative self schemas, which you build up through your early childhood experiences.nIt's a view you have of yourself from actions of others e.g. if you give a drawing to your mom and she says it's useless and rips it up, you believe that you can't do anything- this schema may then be reinforced later in life at school or work 

Beck also proposed a cognitive triad where you have a negative view of yourself, then you have a negative view of the world and then a negative view of the future in a cycle e.g. if you lose your job- it may be difficult for individuals to break out of the cycle 

HOWEVER... not everyone who loses their job becomes depressed so it doesn't explain the behaviour of the whole population 

It also doesn't show cause-effect as the depression may cause negative views about yourself, Lewisohn (1981) found that there was no relationship between negative thoughts and future depression

Nolen- Hoeksma et al (1992) found that a negative attribution style in older children can predict future depression- but only in those children that have suffered stressful life events- this means there still needs to be an environmental trigger, Diathesis Stress Model?