If you feel that missed out on the cannabis stock bonanza of the last few years, don't fret. There's another upcoming opportunity that's shaping up to be even bigger: psychedelics. 

As outlandish as taking LSD or psychedelic mushrooms for their therapeutic effects may seem, these budding psychedelic medicines have the potential to revolutionize mental healthcare. That's especially true for some of the most difficult to treat issues that psychedelics may be useful for, like addiction and post-traumatic stress disorder (PTSD). Even though psychedelic therapies are still in their infancy, I think there are already a few promising (and public) companies that are worth a $1,000 investment.

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1. Compass Pathways

Compass Pathways (CMPS -5.66%) is one of the psychedelic therapy industry's key influencers, and it also has the makings of a growth stock par excellence. 

Its lead program is called COMP360, and it's a psilocybin therapy for treatment-resistant depression. COMP360 is in phase 2b of clinical trials, and it's already been given a breakthrough therapy designation by the U.S. Food and Drug Administration (FDA), so it may not need to spend as much time in clinical development as it might otherwise, which is good news for the estimated 100 million people worldwide that could be helped by the drug. Provided that the ongoing trials go as planned, management aims to start testing the drug for indications outside of depression, which could potentially increase its total addressable market (not to mention its revenue in the years after approval).

But Compass doesn't intend for patients to take COMP360 in isolation. In fact, the real innovation in the company's business model is that it aims to provide both the drug itself (COMP360) as well as the close support from mental health professionals that patients will need to gain the beneficial effects from their therapeutic psychedelic experience. Plus, having a trained therapist on hand during a therapy session will also help patients feel more comfortable and minimize risks.

To ensure that these therapists are prepared to practice psychedelic therapy effectively, Compass developed an in-depth training program and published it in leading psychiatry journals. That's sure to give it credibility with the experts in the field and help to establish it as a leader in the space. 

If you're sold on investing in Compass, there's an important milestone coming up to keep a close eye on. Management expects data from the COMP360 clinical trial in late 2021, so it may make sense to buy the stock now.

2. MindMed

Unlike other psychedelic drug developers, Mind Medicine (MNMD -5.66%) is in the process of developing several therapies that are to be non-hallucinogenic (in addition to a slew of therapies that do produce hallucinogenic effects). This means that, if approved, they can be used to treat chronic conditions like attention deficit hyperactivity disorder (ADHD) or addiction without minute-to-minute supervision by a clinician like what would be necessary with hallucinogenic therapies. So far, its micro-dosed LSD project for ADHD treatment (which produces negligible hallucinogenic effects) is in phase 2a, meaning it has already passed basic safety testing. 

Right now, one of MindMed's hallucinogenic therapies, which also utilizes LSD, is in phase 2b clinical trials for anxiety. If the project goes as planned, the company could have a shot at stealing a significant portion of the global market for anti-anxiety drugs, which is valued at $4.7 billion annually. Likewise, its ADHD drug could have a total addressable market of $9.5 billion. Shareholders will need to wait more than a few years before MindMed's development pipeline will start to pay off, however. 

In the meantime, there are a few milestones that will spur the stock's growth. It recently acquired a healthcare machine learning start-up in exchange for 300 million Canadian dollars in stock. And earlier this month it initiated a phase 1 clinical trial for an LSD neutralizer drug that clinicians could someday use to control their patients' psychedelic therapy experiences more precisely. Later this year, it might even be listed on the NASDAQ instead of over the counter (OTC) -- so investors should seriously consider buying sooner if they want to capture the full benefit of the stock's rise.