Psilocybin has an Effect in Treating Major Depressive Disorder
Highlights
- Major Depressive Disorder is a major economic and social burden for Americans and treatment options are only effective in some cases.
- 24 study participants completed two psilocybin sessions and depression symptoms before and after were monitored with clinician assessments.
- 17 of the 24 participants had a significant decrease in depression scores and 13 of these were determined to be in remission, having no depression symptoms after four weeks.
- Psilocybin is an effective treatment for Major Depressive Disorder, supporting previous findings.
Keywords
GRID Hamilton Depression Rating Scale (GRID-HAMD): A 17-item questionnaire used to determine depression levels. The severity of depression is assessed using the total score out of 24 [2].
Ketamine: A newer intervention for MDD that can reduce depression symptoms within hours of the first dose, with effects lasting up to 2 weeks. However, ketamine has a high potential for abuse and moderate psychological risk that requires medical monitoring [2].
Major depressive disorder (MDD): A mood disorder characterized by persistent feelings of sadness and loss of interest. It can also be accompanied by a lack of energy, sleep problems, and appetite changes [1].
Psilocybin: A classic hallucinogen that increases the neurotransmitters serotonin and glutamate in the brain [2].
Selective Seratonin Reuptake Inhibitors (SSRIs): Typically the first line of treatment for MDD, these are medications that increase the amount of serotonin in the brain. Serotonin is a neurotransmitter thought to be responsible for mood and motivation [2].
Statistical Manual of Mental Disorders, 5th Edition (DSM-5): A diagnostic tool used by psychiatrists and other mental health professionals for assessing mental disorder types and severity in patients in the United States [1].
Background/Scientific Questions
Major depressive disorder (MDD) is a public health concern that affects more than 300 million people worldwide[2]. In the United States, MDD is the number one cause of disability and has an economic cost of more than $2 billion every year. Currently, available treatments only help two-thirds of patients, while being less effective for the remaining third.
Psilocybin is a hallucinogenic compound that is derived from the psilocybin mushrooms. Since its introduction to Western society in the 1960s, research has suggested it could be effective as a treatment for a variety of mental disorders. Previous studies have shown that psilocybin can be an effective treatment for depression among patients with life-threatening cancer or treatment-resistant depression.
While current therapies, such as SSRIs and ketamine have variable efficacy and can cause unwanted adverse effects, psilocybin has the potential to provide a faster and longer-lasting antidepressant effect in patients with MDD [1]. In the article, “Effects of psilocybin-assisted therapy on major depressive disorder,” researchers describe a study in which they used psilocybin to investigate its effect in patients with MDD and predicted that the intervention would cause a significant decrease in depression severity with little to no adverse events.
Methods
This study was conducted using a randomized sample of 27 people with MDD at the Center for Psychedelic and Consciousness Research in Baltimore, Maryland. The participants were then separated into two groups: an immediate treatment group and a delayed treatment group. The delayed group was created to separate the effects of psilocybin intervention in the immediate group from symptom improvement that could occur without any treatment (Figure 1). This can allow researchers to determine the effectiveness of psilocybin treatment long-term.
The participants were assessed over a 16-week period (Figure 2) using the Structured Clinical Interview for DSM-5 and the GRID-Hamilton Depression Rating Scale (GRID-HAMD), both of which are commonly used to assess depression levels in patients.
The delayed treatment group experienced eight weeks on a waiting list before the initial preparation meetings. During this time, they underwent two depression assessments at the same time as the immediate intervention group, during weeks six and eight. The first psilocybin session for the delayed group was during week 11, with the second during week 12. The final depression assessments were given during weeks 13 and 16 [2].
Results
The results ultimately support the researcher’s hypothesis that psilocybin would affect participant depression severity after two treatments (Figure 3 and Figure 4).
At week 4 for the immediate group and week 12 for the delayed group:
17 participants (71%) had a clinically significant response to the treatment
13 participants met the criteria for remission of depression
The researchers found no serious, fatal, or long-lasting adverse effects of psilocybin treatment in any of the participants
They found only mild headaches occurred during 16 of the 48 sessions, or in ⅓ of sessions.
The secondary scales supported these results, showing a decrease in self-reported depression symptom severity and clinician-assessed anxiety symptom severity after treatment.
In the weeks following treatment, researchers determined the psilocybin administered had little to no potential for abuse. This supports the researcher’s hypothesis that psilocybin treatment would be a safer alternative to newer ketamine treatments.
A clinically significant response to psilocybin treatment was defined as a greater than 50% decrease from the first assessment during the preparation period. Symptom remission or no sign of depression was defined as a score of 7 or lower on the GRID-HAMD. The researchers also assessed other aspects of the participants’ symptoms, such as suicidal ideation and anxiety using various other secondary scales in which participants self-reported their depression symptoms.
Implications
This research finds that psilocybin, in conjunction with psychotherapy, can produce large, rapid, and sustained antidepressant effects. The effects of psilocybin with psychotherapy are greater than that of psychotherapy alone and common antidepressant medications alone.
Further, psilocybin has an antidepressant effect after a single session, providing an advantage over commonly used antidepressants, which can take weeks to months to have an effect. Unlike the typical SSRIs, psilocybin does not require daily administration. Based on current research, psilocybin could soon be used as a common treatment for MDD, especially for individuals with treatment-resistant depression.
Future studies could further this research by including a larger and more diverse sample of participants, a placebo control group, an active treatment group, and varying types and degrees of psychotherapy offered with psilocybin treatment. However, this is still emerging research. In the future, studies can focus on more diverse patient samples, examining differences in age and sex. This study was also only conducted with one form of psychotherapy, so it would be valuable to compare the results here with similar studies conducted with varying types and degrees of psychotherapy to determine the most effective combination.
References
- Bains, N., & Abdijadid, S. (2021). Major Depressive Disorder. In StatPearls. StatPearls Publishing. http://www.ncbi.nlm.nih.gov/books/NBK559078/
- Davis, A. K., Barrett, F. S., May, D. G., Cosimano, M. P., Sepeda, N. D., Johnson, M. W., Finan, P. H., & Griffiths, R. R. (2021). Effects of Psilocybin-Assisted Therapy on Major Depressive Disorder: A Randomized Clinical Trial. JAMA Psychiatry, 78(5), 481–489. https://doi.org/10.1001/jamapsychiatry.2020.3285
I am a graduate student at The University of Texas in Dallas. My primary interest is in neuroscience, but I would try to learn about anything I could if given the opportunity. I want to know why people do what they do and how to use that for policy reform in government and education. I have a dog named Koda and you can catch me going on long walks and sharing my popcorn with him.
