Opportunities and Limitations of the N-of-1 Clinical Trial Design in Homeopathy Research

Background: The randomised controlled trial (RCT) is considered the ‘gold standard’ for establishing treatment efficacy or effectiveness, but it cannot inform if an intervention will be effective in a particular individual. Given homeopathy’s personalised approach to treatment, there is intrinsic logic in exploring the opportunities for a supplementary research approach: the N-of-1 clinical trial, in which each subject is his or her own control for the test intervention. To date, no N-of-1 trials in homeopathy have been published in the peer-reviewed literature.

Objective: To examine the opportunities and the limitations of applying the N-of-1 clinical trial design in homeopathy research, illustrating these by an example of a planned N-of-1 trial.

N-of-1 Trial Design: The value of the N-of-1 approach is its basis on single-case investigative design while integrating many conventional RCT approaches, such as randomisation, blinding, and crossover study design. In general, limitations are as for conventional crossover RCTs, being recommended restrictively for chronic stable, episodic, periodic or seasonal conditions, and for interventions with relatively rapid onset and cessation of effect, with negligible carryover. Data from several similar N-of-1 trials can be aggregated, offering potential for more generalisable conclusions.

Example: Planned investigation of differences in short-term clinical outcomes for patients with seasonal allergic rhinitis in two different series of N-of-1 trials, comparing antihistamine with (1) an individualised homeopathic prescription or (2) Galphimia glauca C6. For each series, data will be aggregated by meta-analysis.

Conclusion: The N-of-1 trial design has the potential to be a relevant and high-quality research tool in contributing to homeopathy research. Its applicability requires evaluation in practice.

Keywords: N-of-1 trial, research methodology, homeopathy, seasonal allergic rhinitis

No conflict of interest has been declared by the author(s).