Download FURTHER IDEAS FOR EVALUATING THE BIOLOGICAL

psychopathology
Evaluation of biochemical factors
in depression
Any explanation for depression involving a
single neurotransmitter such as
Norepiniphrine or Serotonin, or a single
hormone e.g. Cortisol, is flawed.
WHY?
The effect of antidepressants
Q. How quickly are serotonin levels raised?
A. Immediately
Q . How long does it take before the effects of
antidepressants can be detected?
A. Several weeks
WHAT DO WE CONCLUDE FROM THIS?
How do the drugs work?
Possibly by increasing
sensitivity of the receiving
neurons. This would take more
time and would explain the
time lag.
Individual differences
If serotonin and norepeniphrine levels were the only cause of
depression everyone would be helped by anti depressant
drugs, BUT this is not the case.
ALSO
Some people with low levels of these neurotransmitters do
not get depressed!!
EXPLAIN THIS!
Cause or effect?
Just because drugs that work on
serotonin levels reduce
depression it is wrong to assume
that lack of serotonin is the
cause.
Why is this?
CAUSE OR EFFECT
Depression may cause changes in neurotransmitters.
Dogs and learned helplessness led to lower levels of
norepinephrine. (Miller et al 1977)
Martin et al (2001) found that the brains of humans showed
changes in serotonin and norephinephrine levels in the basal
ganglia (subcortical brain) after interpersonal therapy
(learning creates new neuronal connections).
Indirect effects
Most antidpressant drugs also suppress REM
sleep.
When deprived of REM sleep symptoms of
depression are reduced. (Wu et al 1992)
REM deprivation may normalise emotions.