For the 300 million people around the globe suffering from a major depressive disorder (MDD), the prescription of antidepressant medication is, in the majority of cases, the first line of therapy.
Market & Research

The global antidepressant drug market was valued at $13.7 billion in 2016 and is projected to grow to $15.9 billion by 2023. This is a compound annual growth rate (CAGR) of 2.1% from 2017-2023. These figures include treatments for MDD, obsessive-compulsive disorder and anxiety.
One hundred million of those diagnosed with MDD are said to suffer from treatment-resistant depression (TRD). This accounts for approximately 33% of MDD cases. An individual is diagnosed with TRD after they are observed to have failed to sufficiently respond to a course of antidepressants within a specified period.
According to a study published in the Journal of Clinical Psychiatry, TRD costs employers upwards of $48 billion each year in the US alone. This cost is a result of direct increases in health care costs for the employer and both a decrease in productivity/increase in absenteeism of employees who suffer from TRD.
It is also worth noting that psilocybin has demonstrated therapeutic benefit in obsessive-compulsive disorder (OCD). At present, no OCD-specific drug class exists to combat the symptoms of the condition. Clinicians instead rely on antidepressants as their pharmacological weapon. OCD has a lifetime prevalence of 2.3% in adults in the US.

The potential for psilocybin products extends beyond just competition with anti-depressant drugs for market share. Other conditions in which psilocybin has demonstrated therapeutic benefit include easing existential anxiety in those with terminal diseases and alcoholism. Alcohol dependence places third in the list of preventable deaths in the US, costing the country $249 billion in 2010.12 Pharmacological interventions exist for alcoholism (e.g. disulfiram). However, epidemiological meta-analyses have shown that these treatments have low remission rates.

Although difficult to source revenue data specific to the future of the psilocybin market, one could conclude that any drug with the potential to address a $48 billion cost to employers due to TRD and $249 billion alcohol associated cost to society, also has the potential to make a momentous impact in the marketplace.
If the legal barriers associated with medical research using psilocybin are lifted in the near future, it will allow for further investigation into the therapeutic potential of the compound, perhaps expanding the use of psychedelic therapy to other affective disorders.
Source: Analysis of the Future Psilocybin Pharmaceutical Market