An antidepressant is a medication
used primarily in the treatment of clinical depression.
Some examples of antidepressants on the market today
are Prozac, Zoloft, Effexor, and Celexa. They also are
not thought to produce tolerance, although sudden withdrawal
may produce adverse effects. Antidepressants create
little if any immediate change in mood and require between
several days and several weeks to take effect.
Some antidepressants, notably the tricyclics, are commonly
used off-label in the treatment of neuropathic pain,
whether or not the patient is depressed. Smaller doses
are generally used for this purpose, and they often
take effect more quickly.
Many antidepressants also are used for the treatment
of anxiety disorders, and tricyclic antidepressants
are used in the treatment of chronic pain disorders
such as Chronic Functional Abdominal Pain (CFAP), Myofacial
Pain Syndrome, and post-herpetic neuralgia.
Antidepressants do not seem to have all of the same
addictive qualities as other substances such as nicotine,
caffeine, cocaine, or other stimulants. There is still
controversy on the definition of addiction. Some argue
that antidepressants do not meet the general requirements
for the common established view. While some antidepressants
may cause dependence and withdrawal they do not seem
to cause uncontrollable urges to increase the dose due
to euphoria or pleasure. For example if some SSRI medications
are suddenly discontinued they may produce both somatic
and psychological withdrawal symptoms, a phenomenon
known as "SSRI discontinuation syndrome" (Tamam
& Ozpoyraz, 2002). When the decision is made to
stop taking some antidepressants it is common practice
to wean off of them by slowly decreasing
the dose over a period of several weeks.
It is generally not a good idea of taking antidepressants
without prescription. Selection of antidepressant and
dosage suitable for the certain case and certain person
is a lengthy and complicated process, requiring knowledge
of a professional. Unqualified approach can only make
things worse. Certain antidepressants can initially
make a depression worse, or can induce anxiety, or can
make a patient aggressive, dysphoric or acutely suicidal.
In certain cases, an antidepressant can induce a switch
from depression to mania or to accelerate and shorten
a cycle (promote rapid-cycling pattern) or hypomania,
or induce a development of psychosis (or just a re-activation
of latent psychosis) in a patient which depression wasn't
psychotic before an antidepressant.
Like many psychiatric drugs, antidepressants were discovered
by accident. The first antidepressants, imipramine,
a tricyclic, and iproniazid, a monoamine oxidase inhibitor,
were discovered in the 1950s. These drugs were found
to have the side effect of improving the patients' mood.
However, the newer SSRI antidepressants were early examples
of rational drug design.
How they are believed to work
The therapeutic effects are believed to be related
to an effect on neurotransmitters, particularly by inhibiting
the monoamine transporter proteins of serotonin and
norepinephrine. Selective serotonin reuptake inhibitors
(SSRIs) specifically prevent the reuptake of serotonin
(thereby increasing the level of serotonin in synapses
of the brain), whereas earlier monoamine oxidase inhibitors
(MAOIs) blocked the destruction of neurotransmitters
by enzymes which normally break them down. Tricyclic
antidepressants (TCAs) prevent the reuptake of various
neurotransmitters, including serotonin, norepinephrine,
and dopamine. Although these drugs are clearly effective
in treating depression, the current theory still leaves
unanswered questions. For example, concentrations in
the blood build to therapeutic levels in only a few
days and begin affecting neurotransmitter activity immediately.
Changes in mood, however, often take four weeks or more
to appear. One explanation holds that the "down-regulation"
of neurotransmitter receptorsan apparent consequence
of excess signaling and a process that takes several
weeksis actually the mechanism responsible for
the alleviation of depressive symptoms. Another theory,
based on recent research published by the National Institutes
of Health in the United States, suggests that antidepressants
may derive their effects by promoting neurogenesis in
Antidepressants can often cause side effects, and an
inability to tolerate these is the most common cause
of discontinuing the medication. Sexual dysfunction
is a very common side effect, especially with the SSRI's.
One exception to this is Wellbutrin (bupropion), which
in many cases results in a moderately increased libido.
Some clinicians have found that adding Wellbutrin to
a regimen of SSRI medications can sometimes alleviate
some degree of sexual dysfunction. However, the mechanism
of action for Wellbutrin appears to be unique and quite
different from other mood elevators, among these being
a stimulant-like effect and concurrent insomnia, especially
in the first few weeks of use. Moreover, some patients,
as seen with most psycho-active drugs, cannot tolerate
Although recent drugs may have fewer side effects,
patients sometimes report severe side effects associated
with their discontinuation, particularly with Paroxetine.
Additionally, a certain percentage of patients do not
respond to antidepressant drugs. Another advantage of
some newer antidepressants is they can show effects
within as few as five days, whereas most take four to
six weeks to show a change in mood. However, some studies
show that these medication might be even more likely
to result in moderate to severe sexual dysfunction.
However, there are medications in trials that appear
to show an improved profile in regards to sexual dysfunction
and other key side effects.
MAO inhibitors can produce a lethal hypertensive reaction
if taken with foods that contain the amino acid tyramine,
such as cheese and wine. Likewise, lethal reactions
to both prescription and over the counter medications
have occurred. Any patient currently undergoing therapy
with an MAO inhibiting medication should be monitored
closely by the prescribing physician and always consulted
before taking an over the counter or prescribed medication.
Such patients should also inform emergency room personnel
and information should be kept with one's identification
indicating the fact that the holder is on MAO inhibiting
medications. Some doctors even suggest the use of a
medical alert ID bracelet.
Antidepressants often make the mania component of bipolar
disorder worse, and should be used with great care in
the treatment of that disorder, usually in conjunction
with mood stabilisers. Their use should be monitored
by a psychiatrist, but in countries such as Britain,
New Zealand and the United States, primary care physicians
are able to prescribe antidepressants without consulting
In particular, it has been noted that the most dangerous
period for suicide in a patient with depression is immediately
after treatment has commenced, as antidepressants may
reduce the symptoms of depression such as psychomotor
retardation or lack of motivation before mood starts
to improve. Although this appears to be a paradox, studies
indicate the suicidal ideation is a relatively common
component of the initial phases of antidepressant therapy,
and it may be even more prevalent in younger patients
such as pre-adolescents and teenagers. It is strongly
recommended that other family members and loved ones
monitor the young patient's behavior, especially in
the first eight weeks of therapy, for any signs of suicidal
ideation or behaviors.
Classes of antidepressant
- monoamine oxidase inhibitors (MAOIs)
- tricyclic antidepressants
- selective serotonin reuptake inhibitors (SSRIs)
- serotonin-norepinephrine reuptake inhibitors (SNRIs)
- selective noradrenaline reuptake inhibitors (NARIs)
- novel antidepressants
- tetracyclic antidepressants
Despite controversy, alternative treatments for depression
such as the herbal remedy St John's wort and the amino
acid derivative SAM-e have also gained popularity in
recent years, although their effectiveness varies. Clinical
trials have shown SAM-e to be as effective as standard
antidepressant medication, with many fewer side effects.
In contrast, a recent study showed St. Johns Wort
to be no more effective than a placebo in case of a
severe depression. (Hypericum Depression Trial Study
Group, 2002) Most studies conclude that St. Johns
Wort is usually as effective against depressions as
other modern medication. Tryptophan dietary supplements,
although banned in many countries, have also been used
as natural antidepressants.
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