There are several main types of antidepressants, categorised based on their mechanism of action on different neurotransmitters in the brain. These include Selective Serotonin Reuptake Inhibitors (SSRIs), Serotonin and Norepinephrine Reuptake Inhibitors (SNRIs), Tricyclic Antidepressants (TCAs), Monoamine Oxidase Inhibitors (MAOIs) and Atypical Antidepressants. Each type works differently and may be prescribed based on the individual’s specific symptoms, side effect profile and response to treatment.