Biological Explanations for Depression
This is essentially the same thing as behaviour and genetics.
Criteria B
●Abnormal behaviour: behaviour that violates a norm in our society, is
maladaptive, is rare given the context of the culture and environment and is
causing the person distress in their daily life.
●Depression: a mood disorder that negatively affects how you feel, the way you
think and how you act. Symptoms include,
○Very low moods and self-esteem.
○Pessimistic and believe they will never be happy again.
○Lack of enjoyment in activities.
○Insomnia and weight changes.
Having a genetic disposition
●Some psychologists believe that both genetics and the environment have an
impact on human behaviour.
●A gene is the unit of heredity, a portion of DNA which codes for a specific
function or trait. We inherit 50% of our genes from each parent.
●Though these genes don’t code for complex behaviours like intelligence, they
may be the building blocks of these behaviours.
●By mapping the human genome, scientists have found some genes that may be
linked to depression.
●The concordance rate in twin studies can be used to determine whether a
disorder has a genetic link.
●The 5-HTT gene has been associated with major depression because it controls
the level of serotonin in the brain. Caspi et al. conducted research about this
gene.
Twin studies
●Twin studies are useful to investigate the influence of genetics on behaviour.
Monozygotic twins (MZ) show a higher concordance rate than dizygotic twins
(DZ).
●However, these concordance rates are never 100% because environmental
factors like diet and exercise impact what genes are expressed.
