Medical treatments for depression

Which antidepressant should be used?

Making a decision about which antidepressant is best for each individual can be complex. The decision is made in consultation with your doctor, after careful assessment and consideration. You can help your doctor's assessment by providing as much information as possible about yourself and your medical history. Important factors include your age, symptoms, other medications and, if female, whether you are pregnant or breastfeeding.

There are many different types of antidepressant medication which have been shown to work, but their effectiveness differs from person to person. Antidepressants take at least two weeks before they start to help, and it may also take some time for the doctor to find the most suitable medication and dosage.

What are the side effects?

Antidepressants can make you feel better, but they won't change your personality or make you feel happy all the time. Like taking any other medication, some people will experience some side effects, and individuals should discuss the risks and benefits with their doctor. People should also ask for information about the medications so that they can make an informed decision.

Depending on which medication is taken, common side effects can include nausea, headaches, anxiety, sweating, dizziness, agitation, weight gain, dry mouth and sexual difficulties (e.g. difficulty becoming/staying aroused).

Some of these symptoms can be short-lived, but people who experience any of these symptoms should tell their doctor, as there are ways of minimising them. The likelihood of a particular side effect happening varies between individuals and medications.

It is not uncommon for people with depression to have suicidal thoughts. Treating the depression effectively will reduce the likelihood of a person hurting him or herself. In the period of time between the person starting antidepressant medication and responding to treatment – which can be more than two weeks – the person should still be monitored closely by the doctor and his or her progress reviewed, as the risk of suicidal behaviour may even be slightly increased, especially in young people.

Types of antidepressants

There is a wide range of antidepressant medication available. Below is a description of the different classes of antidepressants used in Australia.

Selective Serotonin Reuptake Inhibitors (SSRIs)

This class includes sertraline; citalopram; escitalopram; paroxetine; fluoxetine; fluvoxamine. SSRIs are:

• the most commonly prescribed antidepressants in Australia
• often a doctor's first choice for most types of depression
• generally well tolerated by most people
• generally non-sedating.

Serotonin and Noradrenalin Reuptake Inhibitors (SNRIs)

This class includes venlafaxine; desvenlafaxine; duloxetine. SNRIs:

• have fewer side effects compared to the older antidepressants
• are often prescribed for severe depression
• are safer if a person overdoses.

Reversible Inhibitors of MonoAmine oxidase (RIMAs)

The class includes moclobemide. RIMAs:

• have fewer side effects
• are non-sedating
• may be less effective in treating more severe forms of depression than other antidepressants
• are helpful for people who are experiencing anxiety or sleeping difficulties.

TriCyclic Antidepressants (TCAs)

The class includes nortriptyline; clomipramine; dothiepin; imipramine; amitriptyline. TCAs are:

• effective, but have more harmful side effects than newer drugs (i.e. SSRIs)
• more likely to cause low blood pressure – so this should be monitored by a doctor.

Noradrenaline-Serotonin Specific Antidepressants (NaSSAs)

This class includes mirtazapine. NaSSAs are:

• relatively new antidepressants
• helpful when there are problems with anxiety or sleeping
• generally low in sexual side effects, but may cause weight gain.

Noradrenalin Reuptake Inhibitors (NARIs)

This class includes reboxetine. NARIs are:

• designed to act selectively on one type of brain chemical – noradrenalin
• less likely to cause sleepiness or drowsiness than some other antidepressants
• more likely to:
  • make it difficult for people to sleep
  • cause increased sweating after the initial doses
  • cause sexual difficulties after the initial doses
  • cause difficulty urinating after the initial doses
  • cause increased heart rate after the initial doses.

Monoamine Oxidase Inhibitors (MAOIs)

This class includes tranylcypromine. MAOIs are prescribed only under exceptional circumstances as they require a special diet and have adverse effects.

Agomelatine

• This is an atypical antidepressant that works in part by stimulating melatonin receptors.
• As with all medicines there are a range of side-effects, and interactions with other medicines so you should discuss it with your doctor.
• Side effects such as headaches and sleep disturbances are quite common.
• A more rare side-effect is that it can affect the function of your liver and so it requires regular follow-up liver tests (a blood test) to be arranged, and generally it is not recommended in people who already have liver problems.

Things to note

• All of these drugs have been shown to be effective as antidepressants.
• When symptoms are directly due to depression, the person is likely to begin to improve after 4-6 weeks of effective therapy. For example, although SSRIs commonly make sleep difficulties or insomnia worse initially, they are associated with improved sleep 4–6 weeks later.
• SSRIs or clomipramie (TCA) would be the first choice if obsessive compulsive disorder symptoms were prominent.

How long are antidepressants usually needed?

Like any medication, the length of time someone needs to take antidepressants depends on the severity of their condition and how they respond to treatment. Some people only need to take medication for a short time (usually 6–12 months), while others may need it over the long term, just like someone with diabetes might use insulin or someone with asthma would use ventolin. Stopping antidepressant medication should only be done gradually, on a doctor's recommendation and under supervision.

The important thing is finding the treatment that's right for you. Just because a treatment has been shown to work scientifically, that doesn't mean it will work equally well for every individual. Some people will have complications, side effects or find that the treatment doesn't fit in with their lifestyle. It can take time, strength and patience to find a treatment that works.

After seeking appropriate advice, the best approach is to try a treatment you're comfortable with and one that works for most people. If you don't see an improvement or experience problems with the treatment, discuss this with your health professional and consider trying another.