Rexulti (brexpiprazole) is not FDA-approved to treat any anxiety disorder. Its approved uses are as an add-on treatment for major depressive disorder in adults, treatment of schizophrenia, and treatment of agitation related to Alzheimer’s disease. That said, there is meaningful evidence that Rexulti can reduce anxiety symptoms, particularly when those symptoms occur alongside depression, and some doctors prescribe it off-label with that goal in mind.
Why Rexulti Shows Up in Anxiety Conversations
Rexulti works by partially activating two types of brain receptors: serotonin 1A receptors and dopamine D2 receptors. The serotonin 1A receptor is the same target that buspirone, a dedicated anti-anxiety medication, acts on. Rexulti has notably high potency at this receptor, which gives it a theoretical basis for calming anxiety even though it was developed primarily as an antipsychotic and antidepressant add-on.
Compared to its close relative aripiprazole (Abilify), Rexulti has stronger activity at serotonin 1A receptors and weaker activity at dopamine D2 receptors. That combination may translate to better anxiolytic effects and a lower risk of restlessness, a side effect called akathisia that can actually mimic or worsen anxiety. In network analyses comparing the two drugs, brexpiprazole had the highest probability of being the best-tolerated treatment across multiple side effects, including anxiety and restlessness.
Evidence in Depression With Anxiety Symptoms
The strongest evidence for Rexulti’s effect on anxiety comes from studies of people who have major depressive disorder with what clinicians call “anxious distress,” meaning significant anxiety layered on top of depression. This is common: roughly half of people with depression also deal with prominent anxiety symptoms.
In clinical trials, patients with MDD and anxious distress who took Rexulti (2 to 3 mg) as an add-on to their antidepressant showed significantly greater improvement than those on placebo across several symptom measures, including inner tension, sleep problems, and an inability to feel emotions. After six weeks of treatment, nearly 80% of patients who started with anxious distress no longer met the threshold for it. Improvements were actually larger in the group with anxious distress than in depressed patients without it, suggesting the drug pulls more weight when anxiety is part of the picture.
This is an important distinction. Rexulti wasn’t tested against a standalone anxiety disorder like generalized anxiety disorder or social anxiety disorder. The anxiety it reduced was occurring within the context of depression. If your anxiety exists mostly on its own, this evidence doesn’t directly apply to you, though the mechanism of action is still relevant.
Off-Label Use for Anxiety
Some psychiatrists prescribe Rexulti off-label for anxiety that hasn’t responded well to first-line treatments like SSRIs, SNRIs, or buspirone. Off-label prescribing is legal and common in psychiatry, where many medications are used beyond their original FDA indications. There are no large, dedicated clinical trials of Rexulti for standalone anxiety disorders, so this practice is based on the drug’s receptor profile, the depression-with-anxiety data, clinical experience, and extrapolation from similar medications.
When used as an add-on for depression, Rexulti is typically started at 0.5 or 1 mg per day and increased to a target of 2 mg. Doctors prescribing it off-label for anxiety generally stay in a similar low-dose range, though specific dosing varies by individual response.
Side Effects to Know About
Rexulti is generally well tolerated at the doses used for depression, but it carries the side effect profile of an atypical antipsychotic. Weight gain is one of the more common concerns. In clinical trials, a meaningful percentage of patients gained 7% or more of their body weight, which is the threshold researchers use to flag clinically significant gain. Other reported side effects include drowsiness, headache, and mild gastrointestinal symptoms like diarrhea (more common at higher doses).
One advantage Rexulti has over some similar medications is a lower rate of akathisia, that unpleasant inner restlessness that can feel like worsening anxiety. This matters because a medication that’s supposed to help anxiety but triggers restlessness can be counterproductive. Open-label comparisons have shown higher rates of akathisia with aripiprazole than with brexpiprazole, which is one reason some doctors prefer Rexulti when anxiety is a primary concern.
How It Fits Into Anxiety Treatment
Rexulti is not a first-line anxiety treatment. If you’re dealing with anxiety, the standard starting points are SSRIs, SNRIs, therapy (particularly cognitive behavioral therapy), or buspirone. These have decades of evidence specifically for anxiety disorders and generally carry fewer long-term risks than atypical antipsychotics.
Where Rexulti tends to enter the conversation is when those first-line options haven’t worked well enough, when depression and anxiety are tangled together, or when a doctor wants to augment an antidepressant that’s partially helping but not fully controlling symptoms. In that scenario, the data showing that nearly 80% of anxiously distressed patients improved after six weeks is genuinely encouraging. For people stuck in a treatment-resistant pattern, Rexulti offers a mechanism that’s distinct from simply increasing serotonin levels, which is all most standard antidepressants and anti-anxiety medications do.