Medication Management

Antipsychotics as Add-On Treatment: Benefits and Metabolic Risks

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

When an antidepressant helps but not enough, one option is to add a low dose of an atypical antipsychotic. The word “antipsychotic” alarms many people, but in this role the medication is being used for depression, not psychosis, and several are FDA-approved for exactly that. The honest picture is a modest average benefit set against side effects that need active monitoring. This guide explains both sides so you can ask better questions before you agree to one.

Which antipsychotics are approved as add-ons for depression

The current FDA labels list the following as adjunctive treatment for major depressive disorder in adults, meaning they are taken together with an antidepressant, not on their own:

Separately, the fixed combination of olanzapine with fluoxetine is approved for treatment-resistant depression, defined on the fluoxetine label as no response to two different antidepressants of adequate dose and duration in the current episode. Other antipsychotics are sometimes used off-label for the same purpose. Approval matters because it means the drug was tested specifically as an add-on in depression, with published side-effect rates in that population.

This is one of several ways to respond to a partial response. Our sibling guide on whether to add a second medication or switch compares augmentation with switching and with non-antipsychotic add-ons.

How much do they actually help?

The most useful independent summary is a 2013 meta-analysis in PLoS Medicine by Spielmans and colleagues, which pooled 14 short-term placebo-controlled trials. All the drugs studied reduced clinician-rated depression scores, and the authors described the effects as small to moderate. For aripiprazole, quetiapine and risperidone, about nine people needed to be treated for one additional remission compared with placebo. Quality of life and day-to-day functioning, however, showed little or no improvement for most of the drugs, and the authors urged caution given the evidence of harm.

A large real-world comparison points the same way. In the VA’s VAST-D trial of 1,522 veterans whose depression had not responded to an antidepressant, 28.9% of those who added aripiprazole reached remission at 12 weeks, compared with 22.3% of those switched to bupropion and 26.9% of those who added bupropion. Aripiprazole beat switching, but not the bupropion add-on, and the authors called the advantage modest.

Put plainly: for some people an antipsychotic add-on is the step that finally works, and those people often notice it within weeks. For many others the difference is small. That is why the decision should rest on a specific person’s history and preferences, and why a defined trial period makes sense.

Metabolic risk: weight, blood sugar and lipids

The labels for atypical antipsychotics warn that the class has been associated with metabolic changes, including high blood sugar and diabetes, unfavorable lipid changes and weight gain. The size of the risk varies by drug and by person, but it is not trivial even with the agents considered gentler. In VAST-D, a quarter of the people on aripiprazole (25.2%) had gained at least 7% of their body weight by week 36, compared with about 5% in the other two groups.

Weight gain matters on its own, and it also matters because it is one of the most common reasons people stop a medication that was otherwise helping. Our guide to weight gain on psychiatric medication covers why it happens and what can be done.

Since a 2004 consensus statement from the American Diabetes Association, the American Psychiatric Association and endocrinology and obesity societies, the standard of care has been to measure weight, waist, blood pressure, glucose and lipids before starting an antipsychotic and to repeat them on a schedule afterward. The details belong on our page about which lab tests psychiatric medications need; the point here is that monitoring should be arranged on day one, not after the scale has moved.

Akathisia, sedation and prolactin

Akathisia is an inner restlessness: an urge to keep moving, pace, shift in the chair or jiggle the legs, often with anxiety that feels worse than the original depression. It is one of the most common side effects of the add-on antipsychotics. In the PLoS Medicine analysis, there was roughly one additional case of akathisia for every four people treated with aripiprazole, and in VAST-D it occurred in 14.9% of the aripiprazole group versus about 5% of the comparison groups. Akathisia is treatable and often dose-related, so it should be reported early rather than endured.

Sedation and increased appetite are more prominent with some agents than others; the meta-analysis linked sedation to quetiapine, the olanzapine combination and aripiprazole. Prolactin can rise with some antipsychotics, which can cause menstrual changes, breast tenderness or discharge, and sexual side effects; the quetiapine label lists hyperprolactinemia among its warnings. Not every agent behaves the same, which is one reason the specific drug matters as much as the decision to augment.

Tardive dyskinesia and AIMS checks

Tardive dyskinesia (TD) is a movement disorder that can develop after longer-term use of antipsychotics: involuntary movements, most often of the mouth, tongue and face, sometimes the fingers or trunk. Every antipsychotic label lists it as a warning, including the newer agents used in depression. The risk is generally linked to cumulative exposure, which is one argument for re-evaluating an add-on rather than continuing it indefinitely by default.

Clinicians watch for early signs using a short structured exam called the Abnormal Involuntary Movement Scale (AIMS), which takes a few minutes and works over video. A baseline AIMS before starting, then periodic repeats, means subtle changes are caught when there are the most options.

Questions to ask before you start

1. Has my current antidepressant had a full trial at an adequate dose, and have we checked whether I am actually taking it consistently?
2. Have medical contributors such as thyroid problems, low B12 or iron, sleep apnea or alcohol been looked at? (Our guide to why an antidepressant stops working lists common ones.)
3. Why this particular antipsychotic, and what are its most likely side effects for someone like me?
4. What are the alternatives: a different add-on, a switch, or a stronger therapy component?
5. What baseline measurements will we take, and when will we repeat them?
6. How will we judge whether it is working, and when will we decide to continue or taper?
7. If I have a personal or family history of diabetes, heart disease or movement problems, does that change the choice?

The integrative side: protecting metabolic health

Because metabolic change is the most common long-term cost, the lifestyle side of care is not decoration here. Regular physical activity, a diet built around protein, fiber and whole foods, steady sleep and limiting alcohol all push in the opposite direction from the medication’s metabolic effects, and they help depression in their own right. Tracking weight and waist at home between visits gives early warning.

Metformin has the best-studied evidence as a medication to counter antipsychotic weight gain. A 2016 meta-analysis of 12 placebo-controlled trials with 743 patients found an average weight difference of about 3.27 kg in metformin’s favor, along with better insulin resistance. Those trials were mostly in people with schizophrenia or schizoaffective disorder taking antipsychotics full-time, so the findings may not translate directly to a low-dose add-on for depression. It is a reasonable question to raise with your prescriber and primary care clinician if weight is climbing.

How Willow & Stone handles add-on decisions

An antipsychotic add-on is one tool, not the default next step. Before recommending one, Dr. Forbes typically reviews the full medication history, looks for medical and nutritional contributors with lab work, and discusses the alternatives. If an add-on is chosen, it starts with baseline measurements and a set review point, and the aim is the minimal effective dose for the shortest useful time. Read more about how we approach integrative medication management, or see how mood stabilizers differ for people whose depression is part of bipolar disorder.

Common Questions

Sources & Further Reading

• DailyMed — Abilify (aripiprazole) prescribing information
• DailyMed — Caplyta (lumateperone) prescribing information
• Spielmans et al. — Adjunctive atypical antipsychotics for major depression: meta-analysis (PLoS Medicine, 2013)
• Mohamed et al. — VAST-D randomized clinical trial (JAMA, 2017; PMC full text)
• de Silva et al. — Metformin for antipsychotic-induced weight gain: meta-analysis (BMC Psychiatry, 2016)
• Consensus Statement: Antipsychotic Drugs and Obesity and Diabetes (J Clin Psychiatry, 2004)

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.