|
Causes of depression
While researchers often talk about ‘finding the cause’ of some
disease or disorder this often obscures the fact that only
part of the story is known.
Some causes are pretty straightforward. We know that a broken
leg is usually the result of some kind of pressure or strain
being applied. Moreover, if you have a broken leg you
typically know when it happened (leg was fine yesterday, today
it is broken) and how it happened (this morning you went
skiing).
Things are not so simple with depression. We have good ideas
about what some of the ‘pressures or strains’ that result in
depression are – but they are not all agreed upon and there
might be others.
For any one person there could be many ‘pressures’ in their
life. It is often unclear when the depression started – much
of the time it gradually has an effect.
We can see another complication by going back to the broken
leg example. Some people suffer from osteoporosis which makes
their bones more fragile (more vulnerable). If you only had a
minor accident when you went skiing, your osteoporosis was
probably as much the cause of your broken leg, since it made
your leg more vulnerable to the effects of pressure. If you
have a major accident, however, the leg will probably break,
osteoporosis or not.
In other words, the causes of depression are some mixture of
‘pressure’ (mild to severe) combined with a vulnerability to
depression (as a sort of ‘psychological osteoporosis’) which
too can range from mild to severe.
As noted earlier, for each ‘type’ of depression, differing
‘mixtures of causes’ have differential relevance. Thus, for
psychotic
or melancholic
depression physical and biological factors are generally more
relevant. By contrast, for
non-melancholic
depression, the role of personality (osteoporosis) and
life-event stressors (accident) are generally far more
relevant.
|