Which antidepressant class is among the earliest developed and is still used when other treatments have failed?

The class of antidepressants known as tricyclic/tetracyclic antidepressants is recognized for being among the earliest developed treatments for depression and other mood disorders. These medications work primarily by blocking the reuptake of norepinephrine and serotonin, neurotransmitters implicated in mood regulation, thus increasing their availability in the synaptic cleft.

Despite the introduction of newer classes of antidepressants, such as selective serotonin reuptake inhibitors (SSRIs), tricyclics are still used, particularly in cases where other treatments have proven ineffective. This is largely because they can be very effective for certain types of depression and are sometimes chosen when patients have not responded to more modern treatments.

In addition, tricyclics have a well-established efficacy profile and can address symptoms of anxiety and sleep disturbances often associated with depression. However, they come with potential side effects and risks, which have led to their more cautious use compared to newer medications, but they remain a valuable option in the treatment arsenal for severe or treatment-resistant depression.

While monoamine oxidase inhibitors (MAOIs) are also one of the earlier classes used, they require dietary restrictions and can have serious drug interactions, which limits their use. Selective reuptake inhibitors are more commonly