Psychedelics—also known as hallucinogens and entheogens—comprise a family of psychoactive molecules that are both found in nature and synthetically engineered in the lab. As a class, psychedelic compounds produce phenomenologically complex and novel experiences that have recently captured the attention of mental health clinicians and researchers. However, psychedelic clinical research and treatment remain limited, with most studies exploring the efficacy and safety of protocols for individuals with anxiety, depression, substance use, and posttraumatic stress disorder (PTSD), while individuals with personal or familial histories of psychosis, psychotic disorders, and bipolar disorder are mostly excluded from treatment and research. The overarching objectives of this thesis included determining 1) whether excluding this group from psychedelic clinical research is justified, 2) when psychedelic drug administration and psychedelic-assisted psychotherapy (PAP) may be contraindicated for this group, 3) if people with a history of psychosis or a psychotic disorder may be able to treat their psychotic symptoms with PAP, 4) if people with a history of psychosis or psychotic disorder may be able to treat their co-morbid conditions like anxiety, depression, substance use, or PTSD with PAP, 5) what a PAP treatment protocol for this group could look like 6) how individuals with reported histories of psychosis and psychotic disorders describe their experiences of psychedelic drug use and 7) whether naturalistic psychedelic use has an overall positive or negative effect on emotional well-being and psychological functioning for this group. Results from the first study—a qualitative study with experts in medicine, mental health, and psychedelics—suggest that certain individuals with histories of psychosis and psychotic disorders may benefit from PAP under the right conditions, such as when psychosis is etiologically connected to traumatic events, when the protocol offers extensive support for the patient, and when psychosis is not the result of amphetamine use or medical conditions such as epilepsy. Moreover, results suggest that the effects of the specific psychedelic that is administered must be carefully considered and support outside of therapy must also be assessed. Other factors such as personality traits, ability to form rapport with a guide or sitter, symptom severity, specific symptom endorsement, symptom duration, age, the presence of physiopathology and more must also be taken into consideration. For the second study, a cross-sectional, retrospective, phenomenological survey report was administered to individuals who reported a history of one or more psychotic experiences and/or diagnosis of a psychotic condition who also had at least one psychedelic drug experience in their lifetime. The survey asked participants to describe one memorable instance of psychedelic drug use and found that in a sample of 100, most individuals (n=88) describe some degree of personal growth resulting from their experience. Many also describe mystical-type experiences, gaining insight or awareness during their experience, heightened appreciation for life, and improved mental health and emotional well-being. Descriptions of symptomatic relief included reduced paranoid thinking, changes in relationships with symptoms, and decreased suicidal ideation. Approximately 11% of the sample described negative experiences including perseverating psychological impairment, symptom exacerbation, and psychedelic-induced suicidality. A slightly larger portion of the sample described mixed-type experiences, i.e., experiencing positive and negative effects alongside each other. The findings of these studies fill a major gap in the literature by suggesting that individuals with histories of psychotic symptoms and disorders may be able to partake in psychedelic studies and treatment under certain circumstances. This is because experts have explicitly stated that psychedelic use is not necessarily contraindicated for everyone with psychotic conditions and symptoms, but rather that most PAP protocols for anxiety, depression and other conditions do not offer enough support. At the same time, exclusion criteria are required by the FDA. Additionally, survey reports from individuals with lived experiences of psychosis further back the position that PAP could be a viable treatment option for this group through their survey reports. Specifically, the high prevalence of positive and therapeutic experiences with psychedelics in naturalistic settings suggests that clinically supervised psychedelic drug use may generate similar or even better outcomes for this population. Although a minority had adverse experiences, it remains to be studied as to whether similar effects might be experienced at a similar rate or similar degree of frequency in clinical studies, which utilize harm reduction strategies, maximize safety, and implement preparatory and integration sessions, elements which were notably absent from reports of adverse experiences in the survey. Results also shed light on what a psychedelic treatment protocol could look like for this group, and how individuals with histories of psychotic experiences and diagnosed psychotic conditions describe their experiences of psychedelic use and the effects of psychedelic drugs on their emotional and psychological functioning.