No one knows the real answer to the question of how antidepressants work. At least not yet, but extensive research continues. They are primarily used to relieve the symptoms of moderate to severe depression but are also prescribed for other conditions, such as obsessive compulsive disorder (OCD), anxiety disorders and chronic pain.
Although how they work in not exactly known, they are believed to increase the activity of certain chemicals in the brain. These chemicals are called neurotransmitters and they function as messengers, used by the nerve cells (or neurons) to communicate with each other. Researchers believe that the neurotransmitters which play a significant role in depression are serotonin, noradrenaline (norepinephrine) and dopamine. They have varying effects including influencing mood, behaviour, learning, emotion, sexuality, appetite, heart rate, blood pressure, blood sugar, memory, pleasure and desire.
To send messages, the neurons release neurotransmitters into the spaces between neurons called synapses. These neurotransmitters bind to receiving units or receptors. They increase the amount of neurotransmitters in the brain, by blocking their re-uptake and reabsorption into the nerve cells that released them, thus prolonging their effect. There are different types of antidepressants which work in different ways but most are based on this principle.
This video shows how antidepressants are believed to work:
The main types are selective serotonin re-uptake inhibitors (SSRIs), serotonin and noradrenaline re-uptake inhibitors (SNRIs), tricyclics (TCAs) and noradrenaline, and the specific serotoninergic antidepressants (NaSSAs) which do not work as serotonin re-uptake inhibitors. MAOIs (Monoamine oxidase inhibitors) which like the NaSSAs work differently and have numerous drug interactions have been rarely prescribed in recent times and are not considered here. When antidepressant treatment commences, the patient is advised to allow at least a month for the therapeutic effects to become evident. It is believed that this is the time it takes for their brain cells to adapt. However, side effects may occur sooner. The most commonly prescribed types of antidepressants used by our helpline callers are SSRIs and SNRIs, with some TCAs still being used.
Commonly Used Antidepressants
Generic Name Brand Name
mirtazapine Remeron, Zispin
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