BIOLOGICAL THERAPIES FOR DEPRESSION
To read up on the biological therapies for depression, refer to pages 451–459 of
Eysenck’s A2 Level Psychology.
Ask yourself
 If a biochemical imbalance is the cause of depression what would be the
treatment?
 Should electroconvulsive therapy be used for depression?
 What do you think are the weaknesses of biological therapies?
What you need to know
DRUG THERAPY: MAJOR DEPRESSIVE
DISORDER
ELECTROCONVULSIVE THERAPY:
MAJOR DEPRESSIVE DISORDER
MAOIs
 Research evidence
Tricyclics
 Evaluation
Selective serotonin reuptake
inhibitors (SSRIs)
 Evaluation
Drug therapy: Major depressive disorder
Individuals with major depressive disorder often have low levels of the
neurotransmitters serotonin and noradrenaline, according to the monoamine
theory. Accordingly, drugs to treat this disorder are designed to rectify these low
levels.
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MAOIs
The MAOIs block monoamine oxidase and by doing so help to prevent the
destruction of noradrenaline. The increased noradrenaline activity leads to a
reduction in depressive symptoms. The MAOIs are reasonably effective in reducing
depression, but they do produce various side effects, such as blocking the
production of monoamine oxidase in the liver, leading to the accumulation of
tyramine. This is dangerous, because high levels of tyramine cause high blood
pressure. Accordingly, depressed patients taking MAOIs have to follow a careful
diet, making sure to avoid foods containing tyramine (e.g. cheese, bananas).
Tricyclics
Tricyclics slow down the re-absorption of serotonin and noradrenaline by the
presynaptic vesicles. Consequently more of the neurotransmitters are left in the
synapse, and so serotonin and noradrenaline activity increase at the postsynaptic
receptors. This is linked to arousal and improved mood. The tricyclics are less
dangerous than the MAOIs, but they can impair driving to a dangerous extent, and
other side effects include dry mouth and constipation.
Selective serotonin re-uptake inhibitors (SSRIs)
The most common drugs used to treat depression are the serotonin re-uptake
inhibitors (SSRIs), of which Prozac is the best known. These drugs are more
selective in their functioning than the tricylics, in that they increase serotonin
activity by blocking the re-uptake of serotonin, so leaving the serotonin to have an
enhanced effect on the postsynaptic neuron without influencing other
neurotransmitters such as noradrenaline. The SSRIs are as effective as the tricylics,
but they possess some advantages. Depressed patients taking SSRIs are less likely to
suffer from dry mouth and constipation than those taking tricyclics, and it is harder
to overdose on SSRIs. However, SSRIs conflict with some other forms of medication,
and Prozac is reported to have severe effects in some people, including suicidal
thoughts where none were experienced previously.
OVERALL EVALUATION OF ANTIDEPRESSANT DRUGS
Effectiveness
 Empirical support for effectiveness. The MAOIs, the tricyclics, and the
SSRIs have proved consistently effective in the treatment of major depressive
disorder, but the tricylics are generally more effective than the MAOIs, and
produce fewer side effects.
 Side effects. All three types of antidepressants have side effects.
 Do not work for all patients. It is not clear why the various drugs are
ineffective with some patients.
 Compliance. There are problems of non-compliance (i.e. discontinuing
mediation, disregarding instructions on dosage and timing) due to the side
effects. However, this is not such an issue with SSRIs because there are fewer
side effects, although it should be noted SSRIs have severe side effects in rare
cases.
 Treats symptoms not causes. Treatments can either cure the processes
causing the disorder (curative treatments) or suppress the symptoms of a
disorder without changing the underlying processes (palliative treatments).
Drug therapy for major depressive disorder is palliative rather than curative,
and consequently there are high relapse rates when the drugs are stopped.
 Relapse rates. Hollon et al. (2005, see A2 Level Psychology page 453) studied
three groups of patients over a continuation period of 12 months: (1) those
who had received cognitive therapy but had no treatment during the
continuation period; (2) those who had received drug therapy but had no
treatment during the continuation period; and (3) those who had received
drug therapy and continued to receive drug therapy throughout the
continuation period. Of those withdrawn from cognitive therapy, 31%
suffered a relapse, 47% of those who received drug therapy throughout
relapsed, and 76% of those withdrawn from drug therapy suffered a relapse.
These findings strongly suggest that drug therapy is mainly a palliative
treatment whereas cognitive therapy is a curative treatment. Thus, drug
therapy is effective only for as long as depressed patients continue to take
medication, as without it relapse rates are high.
 Drugs work less well with those who have already been treated with
drug treatment. Leykin et al. (2007, see A2 Level Psychology page 454)
found the recovery rate in patients treated with the selective serotonin
reuptake inhibitor paroxetine was nearly 60% among those who had never
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received drug therapy before but was under 20% among those who had
received drug therapy for depression twice or more in the past. This
compares unfavourably to cognitive therapy because approximately 40% of
patients who had received drug therapy before recovered when given
cognitive therapy. This suggests that it is not just that those with persistent
depression are harder to treat but that once the biochemical systems have
been affected by drugs then subsequent drug therapy has less impact.
Placebo effect. The placebo effect occurs when patients given an inactive
substance or placebo (e.g. a salt tablet) show significant reductions in their
symptoms. It is difficult to know how much any improvement is due to the
drug and how much to the placebo effect, i.e. the patient improves because
they expect the drug to work.
Appropriateness
 Individual differences. About 30% of patients fail to respond to any given
drug or show only very modest beneficial effects, therefore drug therapy is
not effective for all, although often patients who do not respond to one drug
do respond to a different one.
 Lack understanding of their effect. We do not fully understand how the
antidepressants reduce the symptoms of depression. It is not as simple as
drugs increasing neurotransmitter levels, because they do this almost
instantly, but can take a few weeks to have an effect. Some would argue we
shouldn’t use them if we do not fully understand how they work.
 Palliative not curative. Antidepressants treat symptoms not causes and so
don’t cure depression.
 Compare unfavourably to cognitive treatment. The fact that patients treated
with cognitive therapy have lower relapse rates, particularly if they have
been treated with drugs on more than one occasion, suggests that cognitive
therapy may be more appropriate than drug therapy, particularly given that
cognitive therapy is far less invasive as it does not have the side effects of
drug therapy.
Electroconvulsive therapy: Major depressive disorder
Electroconvulsive therapy (ECT) was based on the observation that epileptics did
not have schizophrenia and so it was concluded that the two disorders were
antagonistic (cannot not have one if have the other). This led to the deduction that
inducing seizures could help treat schizophrenia and this was done initially using
drugs such as camphor and then cardiazol. It was then discovered that electric
shocks could produce seizures and that ECT had better outcomes than cardiazol.
ECT was then used for other mental disorders such as depression.
ECT involves passing an electric current through the head to produce brain seizures.
It used to be a dangerous process and result in patient terror and broken bones
because traditionally no anti-anxiety drugs were used so the whole body would be
in seizure. The modern use of ECT has a number of improvements including muscle
relaxants to minimise the convulsions and the use of anaesthetics so that the patient
is asleep during the treatment and so does not experience the same anxiety. In
addition, bilateral ECT (administering ECT to both brain hemispheres) has been
mainly replaced by unilateral ECT (applying it only to the non-dominant
hemisphere) to reduce any memory loss.
Studies designed to assess the effectiveness of ECT often compare it against
simulated ECT, in which patients are exposed to the equipment and believe falsely
that they have received ECT. This is done to ensure that the beneficial effects of ECT
are genuine and not simply a placebo effect—seeing the equipment and believing
that you are receiving shocks might be enough to reduce symptoms in the absence
of any actual shocks.
RESEARCH EVIDENCE FOR ECT
 Janicak et al. (1985, see A2 Level Psychology page 455) found that 80% of all
severely depressed patients responded well to ECT, compared with 64%
given drug therapy.
 ECT is also often the treatment of choice in the case of patients with very
severe depression when rapid reduction in symptoms is especially
important. This can be essential in cases of severe depression in which
suicide attempts are possible.
 Petrides et al. (2001, see A2 Level Psychology page 455) reported that
between 65% and 85% of depressed patients had a favourable response to
ECT.
 Pagnin et al. (2004, see A2 Level Psychology page 455) carried out a metaanalysis which concluded that ECT was more effective in the treatment of
depression than antidepressants or simulated ECT.
EVALUATION OF ECT
Effectiveness
 ECT is highly effective. Certain patients benefit more from ECT than others.
De Vreede, Burger, and van Vliet (2005, see A2 Level Psychology page 456)
identified four patient factors predicting good response to ECT: age above 65
years, the absence of a psychotic depression (involving more severe
symptoms), the absence of a personality disorder, and responding well to
antidepressants.
 ECT is used when drug treatment fails. ECT can be an effective treatment
when patients have been unresponsive to drug treatment.
 Treats symptoms not causes. ECT reduces the symptoms of depression; it
does not produce a cure. Thus, it is a palliative rather than a curative
treatment.
Appropriateness
 ECT is consistent with the biological basis of depression. Some of the
symptoms of depression seem to involve deficient functioning within the
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brain, and so a form of treatment that alters brain functioning may well
prove to be appropriate.
Side effects. Memory loss, other cognitive impairments, and possible
neurological damage do question the appropriateness of the treatment.
However, this must be balanced against the fact most side effects are
relatively short lasting.
Memory loss is not permanent. The American Psychiatric Association and
the British National Institute for Health and Clinical Excellence have both
concluded that ECT does not cause permanent brain damage.
We do not understand how it works. Some would argue that because we
do not understand how it works then we should not use the treatment. This
is the equivalent of hitting a computer to make it work, we have no idea what
the true effects are.
Ethical issues. Issues of protection and informed consent are raised because
most patients dislike receiving ECT, and some might be put under excessive
pressure to become involved in this form of therapy. Historically it was used
as a form of punishment and to exert control over patients.
Reductionism. ECT only focuses on one level—the biological, and so ignores
the psychological approach to treatment.
Dosage. ECT is generally most effective at reducing symptoms when given to
both hemispheres at a high dose. However, this produces the most severe
side effects. Thus, therapists have to strike a delicate balance between
effectiveness on the one hand and unwanted side effects on the other.
Individual differences. De Vreede et al.’s (2005) research shows ECT works
better for some than for others.
So what does this mean?
We have considered two forms of biological therapy for depression, drugs and ECT.
Both have been assessed in terms of effectiveness and appropriateness and this
leads to the conclusion that tricyclic drugs are generally better than MAOIs because
they have fewer side effects.
SSRIs may be better again as they are harder to overdose, have fewer side effects,
and so help resolve the issue of non-compliance, but unfortunately they do have
severe side effects in some case as they have been reported to cause suicidal
thoughts where there were none previously.
Thus, all biological treatments raise issues of appropriateness such as side effects,
individual differences, and the fact they treat the symptoms not the causes, which
leads to a high relapse rate. This last criticism is a key weakness as this makes
biological treatments palliative because they manage the disorder rather than cure
it and so we need to consider if psychological treatments offer more hope of a cure.
Evidence suggests that this is the case as drugs have been compared negatively to
cognitive therapy.
Over to you
(a) Outline one or more biological therapy(ies) for depression. (9 marks)
(b) Evaluate the therapy(ies) described in (a). (16 marks)