The Science

To understand how anti-depressants work, you have to know how impulses are carried in the brain.  Messages in the brain travel as electrical impulses in cells called neurons. Chemicals known as neurotransmitters diffuse across the gaps between neurons to allow impulses to pass between one cell and another. The brain's main neurotransmitter is called seratonin, though noradrenaline may be involved too. Hence, an impulse in the first neuron causes it to release neurotransmitters from its end, which diffuse across the gap where they will bind with receptors on the next neuron. When enough molecules of neurotransmitter are joined to the next neuron, an electrical impulse will be generated.  The neurotransmitters are then taken up again and re-synthesised in preparation for the next release.

Chemically, depression is thought to be caused by abnormalities with the levels of neurotransmitter in the brain, such as low levels of serotonin.  Therefore, anti-depressants attempt to restore the efficient transmission of neural messages by increasing the concentration of neurotransmitter. This means that the neurons at the mood centres of the brain make more impulses then they normally would, which is especially effective when someone is feeling low.

Types of Antidepressants:

·          SSRI's (Selective Serotonin Re-uptake Inhibitors)

These act to prevent the re-uptake of serotonin after an impulse, so that more impulses can happen. These are usually the first line of treatment for severe depression.  Names include paroxetine, setraline, escitalopram, and fluoxetine (made by prozac).

·          Tricyclic antidepressants (TCA's)

This type of antidepressant is named after its atomic structure, and it is generally thought to work by inhibiting re-uptake of neurotransmitters too.  Although it has an instant chemical effect, low moods and depressive symptoms do not improve for several weeks. They have been mostly replaced by the use of SSRIs which are thought to have fewer side effects and are also thought to be less harmful if used in deliberate overdoses. They tend to be used for depression with no obvious external cause, called endogenous depression. Their names include: amitriptyline, amoxapine, clomipramine, doxepin, imipramine, lofepramine, trimipramine, nortriptyline, maprotiline, mianserin, trazodone, mirtazapine.

·          Monoamine Oxidase Inhibitors (MAOIs):

These act to prevent the action of an enzyme which breaks down neurotransmitters called monoamine oxidase.  People on MAOI's must follow strict dietary control, because MAOI's prevent the breakdown of an amino acid which can be dangerous if allowed to reach a high level.

Taking Antidepressants

Any given antidepressant will be effective in only about 60 – 80% of the people who take it, but as there are so many types, it is very likely that someone will be able to find one that helps.  None of what's written on this page is intended to replace a doctor's advice, but having taken antidepressants myself, worked in a psychiatric hospital, and studied psychology, this is what I have found useful to know:

·          Don't combine taking more than one sort of antidepressant at once, and remember that medication stays in your system for some time after you have taken it. Too much serotonin as a result of overdoes can be dangerous, leading to 'Serotonin Syndrome', characterised by high temperature, muscle spasms, tremor and convulsions.   This is also why you shouldn't mix antidepressants with 5-HTP supplements (5-HTP is an amino acid which is used to produce serotonin), or with St John's Wort (a popular herbal remedy for depression).

·          The use of recreational drugs is never a good idea when you have pre-existing mental health problems. However, anything which affects the serotonin system, in particular Ecstasy, is a seriously bad idea when on antidepressants. In fact, Ecstasy can actually trigger depression by damaging the serotonin system.  If you have ever had paranoid tendencies or hallucinations, or anyone in your family has, it's worth knowing that cannabis can trigger psychotic symptoms.

·          When you first taking antidepressants there maybe some side effects.  I took fluoxetine which made me feel sick and unable to sleep. I found that I felt less sick if I took the pills with some food, and slept better if I took it in the morning.  These effects wore off after a few weeks.

Suicidal Tendencies:

One recognised problem with antidepressants is their tendency to increase suicidal tendencies, though this increase is only 4.3%.  However, because antidepressants take a few weeks to become fully effective, they may give a depressed person more energy to act upon their suicidal thoughts before giving him or her increased mood.  Of course, it goes without saying that the risk of suicide is much higher in untreated depression.

Summary

Antidepressants will not always be the first or most appropriate solution for someone's mental health needs. There are many non-drug treatments which may be equally or more effective for those with depression. Exercise has been found to be effective in the treatment of mild to moderate depression, and there are many therapeutic methods available which may also help. However, antidepressants do have an important role to play in addressing the neurochemical side of depression, and other conditions like anxiety and OCD for example.  They allow a space in which a person may reflect and make changes to their life, and when positive change has been made through other therapies, then the medication is no longer needed.  Antidepressants assist improvements in mental health, they are not the source of that improvement in themselves.