Psilocybin-assisted Existential, Attachment and RelationaL (PEARL) Therapy for Caregivers of Patients With Advanced Cancer

Inclusion Criteria: * 18 years of age or older. * Participant must reside in Ontario, Canada. * Ability to speak and read English (participant to provide written informed consent and participate in PEARL intervention, as determined by study personnel). * No cognitive impairment indicated in medical record or by the primary care physician. * Primary or significant caregiver of a patient with advanced cancer enrolled in a companion trial of PEARL for patients with advanced cancer or caregiver of a patient receiving psilocybin-therapy through the Special Access Program (SAP) at University Health Network (UHN); such patients will have been recruited from psychosocial oncology or palliative care clinics at Princess Margaret (study physicians to assess appropriateness of inclusion and whether treatment will support the family system). * At least mild anxiety or depression symptoms, defined as a score of \>5 on the General Anxiety Disorder-7 (GAD-7) or \>8 on the Patient Health Questionnaire-9 (PHQ-9). * Interest in and ability to participate in and complete the PEARL intervention and protocol as outlined. * Normal hepatic functioning as determined by prior medical history or/and screening bloodwork (international normalized ratio \[INR\]\<1.5, aspartate aminotransferase \[AST\]/alanine transaminase \[ALT\] \< 2x upper limit of normal, normal range bilirubin, platelets ≥150). * Normal renal functioning as determined by prior medical history or/and screening bloodwork (estimated glo…