Psilocybin, the "magic musghroom" chemical, has come a step closer to becoming a legal treatment for difficult cases of depression after the Food & Drug Administration (FDA) gave its "Breakthrough Therapy" designation to a psychedelic-based treatment of a UK-based company.

This week, Compass Pathways announced the designation, which it says will fast track the FDA’s review of the treatment for possible approval. The FDA approved a trial of the chemical in the US for this first time in August this year, Daily Mail reports.

According to the Drug Enforcement Administration (DEA), psilocybin is a Schedule I drug, but it is also among several other psychedelic drugs that have lately gained popularity as promising treatments for various mental conditions. Psilocybin along with other psychedelics such as LSD and DMT are federally classified as Schedule I controlled substances in the US, meaning they aren’t considered to have any accepted medical use. 

According to the results of the said trial, psilocybin showed favorable outcomes for patients with depression that have otherwise shown no improvements with conventional treatments. With the rare classification, the time taken to get it approved could basically be cut in half.

Several patients in the US never feel like they have found an effective treatment for depression, despite the condition being exceedingly common in the country. While the combination of psychotherapy combined with medication has proven beneficial to the majority of some 40 million adults who suffer from some degree or form of depression, quite a few have failed to see benefits from the two-pronged approach.

Other traditional medications, such as the commonly prescribed selective serotonin reuptake inhibitors (SSRIs) and other antidepressants, do not work for all patients. Even when they work, the patient has to undergo unpleasant side effects in many cases, including nausea, insomnia, and sexual dysfunction. Also, in most cases, the drugs take months for patient to actually feel its effects.

That said, psilocybin works in a rather contrasting fashion as compared to conventional medicines. SSRIs, as well as other approved anti-depressants, tend to make the amygdala - the brain's emotional center - less sensitive to intense negative feelings. However, psilocybin does the exact opposite. When ingested, the chemical works to encourage emotional activity in the amygdala, but at the same time, patients are better able to process these feelings and feel relief from their depressive symptoms.

One research suggested that psilocybin "resets" neural circuits which tend to create negative feedback loops in the brain, causing depression.

Acknowledging the growing evidence supporting the positive effects of the drug, the FDA gave Peter Thiel-backed Compass Pathways the green signal to expand clinical trials to the US by August. Now three moths later, with the FDA's designation of psilocybin as Breakthrough Therapy, it would shorten the period between clinical trials and its release to the market.

It takes about 12 years to get a drug approved by the FDA, on average. However, with the new designation, that period cuts down to 5.7 years, which is less than half the time it would usually take.

George Goldsmith, the executive chairman of Compass Pathways, called the designation "great news for patients" in a statement.

"We are excited to be taking this work forward with our clinical trial on psilocybin therapy for treatment-resistant depression," he said.

"The FDA will be working closely with us to expedite the development process and increase the chances of getting this treatment to people suffering from depression as quickly as possible."