Medication Management

Add a Second Medication or Switch? How Augmentation Decisions Are Made

By Dr. Stacey Forbes, DNP, APRN, PMHNP-BC · Updated October 12, 2026

A partial response is one of the most common places to land on an antidepressant. You feel better than before, but not well. At that point there are three broad moves: get more out of the current medicine, switch to a different one, or add a second treatment on top. Adding is called augmentation. This guide explains how prescribers weigh those options, what the main add-on categories are, and what the evidence can and cannot tell you.

Three moves after a partial response

NICE’s depression guideline lists the options plainly when an antidepressant has given no or only a limited response. They include increasing the dose if the medicine is well tolerated, switching within or between classes, adding a psychological therapy or a group exercise program, and — with an understanding that side effects may increase — combining medications.

It also includes a caution that surprises some people: higher doses may not be more effective and can increase side effects. More is not automatically better, which fits the minimal effective dose philosophy.

A rough way to think about the choice:

• Little or no benefit after a fair trial usually points toward a switch. There is not much gain to protect. Our guide to switching antidepressants covers how that is done.
• A real but incomplete benefit makes augmentation more attractive, because a switch would risk losing the progress you have made.
• Good benefit with troublesome side effects often leads to a dose adjustment, a different medicine in the same class, or treating the side effect directly.

Check these before adding anything

NICE advises that when depression has not responded, the first conversation should cover adherence — including doses skipped or reduced because of side effects — and any personal, social, physical or mental health factors that could explain it. If that does not explain it, the next step is to review the diagnosis and look for other conditions that limit response. An integrative evaluation takes that advice seriously before a second prescription is written.

• Adherence and timing. Missed doses, irregular timing, or quietly taking less to manage a side effect are common and fixable.
• Sleep. Ongoing insomnia, a disrupted schedule, or possible sleep apnea can keep mood low no matter what medicine is used. See why sleep medication alone often does not fix insomnia.
• Thyroid and other labs. Thyroid problems, low iron or B12, and other medical issues can mimic or worsen depression. Our overview of lab tests that can change treatment explains what may be checked, and thyroid health and mood goes deeper.
• Alcohol, cannabis and other substances. These can blunt antidepressant response and complicate any combination. See anxiety, depression and substance use.
• Other medications and supplements. Interactions can lower drug levels or add side effects that feel like depression.
• The diagnosis itself. Unrecognized bipolar features, ADHD, trauma, or a medical condition can all look like “treatment-resistant” depression.

Our articles on the deeper causes of treatment-resistant depression and integrative medication options for treatment-resistant depression explore these factors in detail. The point here is sequence: fix what can be fixed, then decide whether a second medicine is still needed.

The main augmentation options

NICE names several categories for people who want to try a combination and accept the possibility of more side effects. It also recommends considering specialist input for these decisions.

Antipsychotic add-ons deserve their own discussion because of their metabolic effects; see antipsychotics as add-on treatment. For the monitoring each option needs, see which lab tests psychiatric medications need. For therapy options that pair well with medication, see the best therapy types to pair with medication.

What STAR*D showed, and why it is debated

The NIMH-funded STAR*D study is the trial most often cited on switching versus adding. It enrolled adults with depression who started on citalopram, an SSRI, and moved those who did not become symptom-free through up to three more levels of treatment.

• At level 2, about a quarter of those who switched medicines became symptom-free, compared with about a third of those who added bupropion or buspirone. NIMH notes, however, that switching and adding were not directly compared: most people chose only one strategy, and the groups differed.
• At level 3, adding lithium or thyroid hormone led to symptom-free status in about one in five, with thyroid hormone causing fewer troublesome side effects.
• By level 4, rates were lower still, at roughly 7 to 10 percent.

NIMH’s summary reports that almost 70 percent of participants who did not withdraw became symptom-free across all levels. In 2023, a reanalysis in BMJ Open by Pigott and colleagues used the study’s original, protocol-specified rating scale and inclusion rules and found a cumulative remission rate of 35 percent — about half the published figure. The original investigators replied in the American Journal of Psychiatry that the data remain strong, and the disagreement has not been resolved.

What holds up either way: each additional step helped fewer people, and no single add-on stood out as clearly best. That is a reason to make each step count — to check the basics first, and to choose an add-on that fits your specific remaining symptoms and risks rather than a default.

How the add-versus-switch decision gets made

In practice, the decision weighs several things together:

• How much the current medicine helped. The more you would lose by stopping it, the stronger the case for adding.
• Which symptoms are left. Persistent insomnia, low energy, or ongoing anxiety each point toward different options.
• Your side-effect history and health. Weight, blood sugar, heart rhythm, kidney function and pregnancy plans all narrow the field.
• Interactions and pill burden. Every added medicine adds interaction checks and another thing to manage.
• Your preferences. NICE stresses shared decisions, and some people would rather try therapy or exercise before another prescription.

NICE also asks prescribers to explain the likely increase in side effects before starting a combination. That honesty matters: a combination that helps mood but adds weight gain or sedation may not be a net win.

Give every add-on a job and an exit plan

An added medicine should have a reason you can state in one sentence — “to help residual low mood,” “to help sleep while the antidepressant works” — and a way to tell whether it is doing that job. Make one change at a time so the result is interpretable, and track a few target symptoms before and after. Our guide on measuring medication response suggests simple ways to do this.

Just as important is the plan for later. Once you have been well for a while, it is reasonable to ask whether both medicines are still needed, and in what order any reduction would happen. Augmentation does not have to be permanent.

How Willow & Stone approaches augmentation

At Willow & Stone, a partial response starts a review, not a reflex. Our longer visits leave room to look at sleep, labs, hormones, nutrition, substances and the full medication list before anything is added, and pharmacogenomic testing can sometimes explain why a medicine underperformed. When a second medicine is the right call, the choice is made together, monitored closely by telehealth, and revisited over time as part of integrative medication management. To talk through your options, book a consultation.

Common Questions

Sources & Further Reading

• NICE NG222 — Depression in adults: further-line treatment recommendations
• NIMH — STAR*D: questions and answers on all medication levels
• Pigott et al. — Reanalysis of STAR*D patient-level data (BMJ Open, 2023)

This article is general education, not advice for your situation. Do not start, stop, or change a medication or supplement without talking to the clinician who prescribes it.