Treating Depression: Antidepressants

Antidepressants are medications used to treat depression by altering the balance of neurotransmitters in the brain. They are one of the most commonly prescribed treatments for depression and are based on the biological approach — the idea that depression is caused by chemical imbalances in the brain.

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How Antidepressants Work

Most antidepressants work by increasing the availability of certain neurotransmitters (especially serotonin) in the synapse:

SSRIs (Selective Serotonin Reuptake Inhibitors)

SSRIs are the most commonly prescribed type of antidepressant. Examples include fluoxetine (Prozac), sertraline (Zoloft), and citalopram.

How they work:

1. Normally, after serotonin is released into the synapse, it is reabsorbed (reuptake) by the pre-synaptic neuron
2. SSRIs block the reuptake of serotonin, preventing it from being reabsorbed
3. This leaves more serotonin available in the synapse
4. The increased serotonin stimulates the post-synaptic neuron more effectively
5. Over time (usually 4–6 weeks), this increased serotonin activity improves mood

SNRIs (Serotonin-Noradrenaline Reuptake Inhibitors)

SNRIs work similarly to SSRIs but also block the reuptake of noradrenaline, increasing the availability of two neurotransmitters. Examples include venlafaxine and duloxetine.

Tricyclic Antidepressants (TCAs)