An emerging treatment for clinical depression has reached an important milestone. This week, the Food and Drug Administration approved Johnson & Johnson’s ketamine-based nasal spray, Spravato, as a standalone therapy for cases of depression that have not responded to other options.

J&J Office has partnered the supplemental approval by the FDA on Tuesday. Previously, Spravato was approved as an add-on therapy for treatment-resistant depression, in combination with oral antidepressants. Expanded use heralds a promising future for ketamine and similar drugs as mental health interventions.

You are good first approved by the FDA in 2019, after years of research suggesting that ketamine therapy can provide unique and fast-acting antidepressant benefits. Although ketamine is perhaps better known as a recreational drug with dissociative effects, it has long been used in medicine as an anesthetic. Before Spravato’s approval, intravenous ketamine had been a growing, if off-label, option for difficult cases of depression. However, Spravato contains a different form of ketamine than the version used intravenously — a chemical sibling called esketamine.

In the years since its approval, Spravato and ketamine have continued to show their potential as a treatment for depression. Studies after its release found, for example, that ketamine CAN above performance other standard alternatives for treatment-resistant depression, such as some antipsychotics. The FDA granted expanded approval to Spravato based on another post-market phase 4 trial, one that compared Spravato alone with a placebo.

The double-blinded, randomized, and controlled trial involved people with treatment-resistant depression, who were assigned to three groups: two groups that received different doses of Spravato twice a week for four weeks and a control group that received a placebo spray. Those on Spravato experienced a significant and sustained reduction in depressive symptoms compared to controls, the study found. Only 7.6% of patients taking a placebo experienced a clear remission of their symptoms, for example, compared to 22.5% of people taking Spravato. The drug also seems to be safe as shown in the first tests.

“Depression that is resistant to treatment can be very complex, especially in patients who do not respond to oral antidepressants or cannot tolerate them,” said Bill Martin, the global therapeutic area head of neuroscience in J&J’s innovative medicine department, in a you statement. “Spravato is now available as a standalone treatment, which means patients can experience improvements in depression symptoms as early as 24 hours and in 28 days—without the need for day- daily oral antidepressants.”

Like any drug, ketamine is not without its risks. When used for depression, common side effects may include sedation, dissociation, and respiratory depression (extremely slow or shallow breathing). These side effects and the potential risk of harmful dependence led the FDA to mandate a special treatment strategy for administering Spravato to patients, known as the Risk Evaluation and Mitigation Strategy, or REMS, which program. People taking Spravato can only do so in clinics or medical offices certified to dispense it, and under direct medical supervision.

However, expanding Spravato into a standalone therapy means more people with treatment-resistant depression will be able to access the drug. In the long term, a big reason why researchers are excited about ketamine is that the drug targets different receptors in the brain that depression binds to than other drugs. Not only does this allow ketamine to potentially help people who have not responded to previous treatments, it could in the future mean the arrival of new drugs which works the same way. And if these drugs can be made safer, then they can also become frontline treatments for depression in general.