Negative experiences of patients using medicinal cannabis: A systematic review of qualitative studies

Aims and objectives: In this study, we systematically reviewed qualitative studies concerning patients' experience with medicinal cannabis (MC) use, to gain insight into the negative effects of MC.

Background: Over the past decades, the use of MC for therapeutic purposes has increased. However, there is conflicting and insufficient data on possible negative physiological and psychological effects of MC treatment.

Design: A systematic review was conducted and the PRISMA guidelines were adopted. Literature searches were conducted using PubMed, PsycINFO and EMBASE. Critical Appraisal Skills Programme (CASP) qualitative checklist used to assess risk of bias in the included studies.

Methods: We included studies focusing on conventional medical treatment using cannabis-based products, approved by a physician for a particular health issue.

Results: Of the 1230 articles identified in the initial search, eight articles were included in the review. Following the compilation of themes in the eligible studies, six themes were identified: (1) MC approval; (2) administrative barriers; (3) social perception; (4) MC misuse/widespread effect; (5) adverse effects; and (6) dependence or addiction. These were grouped into two meta-themes: (1) administrative and social aspects of MC use; and (2) experiences of the effects of medicinal cannabis.

Conclusions: Our findings call for specific attention to unique consequences associated with MC use. Further research is needed in order to assess the degree to which negative experiences associated with MC use may affect various aspects of patients' medical condition.

Relevance to clinical practice: Describing the complex experience of MC treatment and its spectrum of consequences for patients may enable physicians, therapists and researchers to provide more attentive and accurate MC treatment to their patients.

Patient or public contribution: In this review, patients' narratives were explored, yet the research methods did not directly involve patients or the public.