Although how they work is not exactly known, antidepressants 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 (nor-epinephrine) and dopamine. They have varying effects including influencing mood, behaviour, learning, emotion, sleep, 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.
The main types are selective serotonin re-uptake inhibitors (SSRIs), serotonin and noradrenaline re-uptake inhibitors (SNRIs), tricyclics (TCAs), and the noradrenaline 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 the people I have supported over the years are SSRIs, SNRIs and TCAs.
Commonly Used Antidepressants
Generic Name Brand Name
amitriptyline Elavil,Tryptizol
citalopram Cipramil
dosulepin Prothiaden
fluoxetine Prozac
mirtazapine Remeron, Zispin
paroxetine Paxil
sertraline Lustral
trazodone Molipaxin
venlafaxine Effexor
Caution: Never stop taking a benzodiazepine or antidepressant abruptly or rush your taper. In the case of benzodiazepines the risks of quitting cold turkey include seizures and psychosis. Always taper off slowly using the Ashton or other recommended method, under the supervision of your doctor.
Ref:
Ashton, C. Heather, 2007. Benzodiazepines: How They Work and How to Withdraw SC: Busatti Corporation.
Frederick, V.B (2014) Recovery and Renewal: Your essential guide to overcoming dependency and withdrawal from sleeping pills, other ‘benzo’ tranquillisers and antidepressants. London: Jessica Kingsley Publishers.
Rang, H.P., Dale, M.M. & Ritter, J.M., 1999. Pharmacology. 4th ed. Edinburgh: Churchill Livingstone.
