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. According to the latest edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM), the DSM-5, MDD is characterized by a specific set of symptoms, the two most defining being a depressed mood and a loss in interest or pleasure that persists for longer than two weeks. MDD is the most prevalent form of diagnosed depression and differs from other forms of depression such as bipolar disorder (manic-depression).
The serendipitous discovery in the 1950s that compounds such as iproniazid and imipramine provided some relief for those suffering from depression (the compounds were originally developed for tuberculosis and schizophrenia, respectively), led to the monoamine theory of depression.1-2 This theory asserts that depression is caused by a depletion of the neurotransmitters serotonin and noradrenaline. In the following decades, the pharmaceutical industry focused their research and development efforts on compounds such as selective serotonin reuptake inhibitors (SSRIs, e.g. fluoxetine [Prozac]) and tricyclic antidepressants (TCAs, e.g. clomipramine [Anafranil]), both of which act on serotonin receptors.
Because conventional antidepressants are the mainstay when it comes to treating depression,3 they account for the majority of revenue generated in the area of depression therapeutics. While antidepressants provide relief in many of those suffering from MDD, there are concerns about the market dominance exhibited by antidepressants as these compounds come with safety issues. These issues include insomnia, drowsiness and most concerningly, an increase in suicidal ideation.4-5 Unfortunately, at present, there are no effective therapeutic alternatives approved by the US Food and Drug Administration (FDA).
Depression Drug Market Figures
- 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.6 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.
Opportunity for Market Infiltration
Life sciences start-up COMPASS Pathways is set to begin stage IIb clinical trials during the first quarter of 2019 in Europe and the US. The clinical trials aim to investigate psilocybin’s potential as a therapy for TRD. If the drug satisfies the regulatory requirements set out by the FDA and the European medicines agency (EMA), psilocybin-assisted therapy is projected to become available as a treatment option to those suffering from TRD by 2021.
Psilocybin has the potential to occupy a portion of the therapeutic market for TRD due to the failings of antidepressants in a subset of the MDD population. This is not to say that antidepressants aren’t a vital weapon in the fight against MDD. In recent years there has been a shift in public perception concerning the effectiveness of antidepressants, along with the accusation that these drugs are being over-prescribed by doctors in the clinic. In a recent six-year study published in The Lancet, researchers analysed 500 trials in which antidepressants were tested against placebo and found that all antidepressants examined were more effective than placebo at treating MDD.7 However, approximately 33% of those suffering from MDD do not respond to these medications.8
It is also worth noting that psilocybin has demonstrated therapeutic benefit in obsessive-compulsive disorder (OCD).9 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.10-11 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.13
While it is 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.
The studies referenced throughout this article have demonstrated that psilocybin is a versatile drug that has therapeutic efficacy in a variety of conditions. These therapeutic effects have been uncovered while the drug remains a controlled substance. 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.