Psilocybin Therapy for Depression in Bipolar II Disorder

Inclusion Criteria:

* Age 18 to 70
* Comfortable speaking and writing in English
* Diagnosis of Bipolar Disorder II with current depression
* Have a care partner/support person available throughout the study
* Able to attend all in-person visits at UCSF as well as virtual visits
* Having tried at least one previous medication trials for their bipolar disorder, each lasting at 6 weeks or more.

Exclusion Criteria:

* Current or previous diagnosis of Bipolar I Disorder
* History of schizophrenia spectrum or psychotic disorder
* Use of psychedelics within the past 6 months, including MDMA
* Current diagnosis of cancer
* Seizures that continue to the present
* Fear of blood or needles
* Regular use of medications that may have problematic interactions with psilocybin, including but not limited to antidepressants (Bupropion allowed), serotonin antagonists, some antipsychotics, dopamine agonists/antagonists, stimulants, opioids, and Lithium.
* A health condition that makes this study unsafe or unfeasible, determined by study physicians