An augmentation strategy adds a second medication or treatment to an antidepressant that is helping but not enough, rather than switching to something new. The logic is to keep whatever benefit you already have and build on it with a different mechanism. Augmentation is usually considered after an antidepressant has been taken at a full dose for at least six weeks with partial response. It is one of the main approaches to treatment-resistant depression and is supported by the STAR*D study, which tested both switching and augmenting after an initial SSRI failed.
The best-supported augmenting agents are atypical antipsychotics such as aripiprazole, brexpiprazole, quetiapine and cariprazine, which are FDA-approved for this use, and lithium, which has decades of evidence and a specific benefit for suicide risk. Thyroid hormone (T3), bupropion, mirtazapine and buspirone are also used. Each has a distinct side effect profile, so the choice depends on your symptoms: sleep and appetite problems might favor mirtazapine, low energy might favor bupropion, and a history of mood swings might point toward lithium or an atypical. Psychotherapy is itself an augmentation strategy with strong evidence. Deep TMS and Spravato are the interventional extensions of the same idea: both are added to an existing antidepressant rather than replacing it. Your Stedfast Psychiatry provider will weigh augmentation against switching based on how much you have improved, what side effects you have, and your history.