How do they work?
It is thought that antidepressants
work by altering the balance of some chemicals in the brain called neurotransmitters, in particular serotonin and noradrenaline.
How long will they take
to work
When starting treatment with
an antidepressant, it is usually 2 to 4 weeks before a full response is seen. It
is therefore worth waiting up to 4 weeks before deciding whether or not the treatment is helping. In older people it may take up to 6 weeks before the full response is seen.
How well do they work?
The symptoms of depression will
improve in about 6-7 out of 10 people who take an antidepressant. However some
people may improve without treatment. In about 3 out of 10 people, symptoms improve
with placebo or ‘dummy’ tablets. In other words they don’t
work in everybody, but you are approximately twice as likely to improve if you take antidepressants compared to no treatment.
Do they have side effects?
All medicines have possible side
effects; the important thing to remember is not everybody gets them. The common
side effects you might experience with the different types of antidepressants are listed below.
Tricyclics
Fairly common side effects include
a dry mouth, drowsiness, constipation, and slight hesitation in passing urine, slight blurring of vision and sweating. They may cause confusion, sexual problems, weight gain, faintness through low blood
pressure and falls (particularly in older people.) Tricyclics are dangerous in
overdose.
SSRIs
The most common side effects
include feeling sick, vomiting, diarrhoea and indigestion. Sexual problems may
sometimes occur.
Some people develop a feeling
of restlessness or anxiety when they first start treatment. There have been some
case reports that claim a link between taking an SSRI and feeling suicidal. There
is not convincing evidence of such a link. However if you become anxious
or agitated or have any suicidal thoughts, particularly in the early stages of treatment, or after an increase in dose, you
should see your doctor as soon as possible.
SNRIs
Side effects are similar to SSRIs. Venlafaxine may cause constipation. It
is not recommended for people with heart problems or high blood pressure.
MAOIs
Individuals taking MAOIs may
have to be careful about eating certain foods containing a substance called tyramine as this may cause a dangerously high
blood pressure. This type of antidepressant is rarely prescribed nowadays. If you are prescribed an MAOI your doctor will give you a list of foods to avoid.
You should find a list
of possible side effects on the leaflet that comes in the medicine packet. With
all antidepressants it is worth keeping on with treatment if side effects are mild at first.
They may ease off after a week or so as the body becomes used to the medication.
However if a side effect persists or is troublesome you should tell your doctor.
It may be that a different treatment would suit you better.
