Menstrual cyclicity of cannabis use: a longitudinal study using phase-aligned cycle time scaling (PACTS).

Zorzini G.; Ly M.; Wahl T.; Gordon J. · Addictive behaviors · 2026

**Background & Methods** This prospective longitudinal study followed naturally cycling individuals with diagnosed or suspected premenstrual disorders (PMDs) for 2-3 menstrual cycles to investigate menstrual cyclicity of cannabis use. Participants completed daily ratings of cannabis use and premenstrual symptom severity using the Daily Record of Severity of Problems (DRSP), with associations modeled using generalized additive mixed models and the novel phase-aligned cycle time scaling (PACTS) method to generate phase-aligned cycle-time variables anchored to menses onset and ovulation. **Key Findings** • Daily quantity of dried cannabis flower used demonstrated statistically significant menstrual cyclicity (p = 0.030), with peak usage occurring before menses onset and around ovulation timepoints. • Core affective symptoms of PMDs moderated cannabis cyclicity (p = 0.004), specifically emotional/rejection sensitivity (p = 0.004) and interpersonal conflicts/problems (p = 0.010), with higher-than-usual daily symptom levels associated with increased premenstrual cannabis flower quantity and lower-than-usual symptom levels associated with decreased premenstrual use. • Findings suggest cannabis use quantity fluctuates meaningfully across the menstrual cycle in individuals with PMDs, potentially reflecting symptom-driven self-medication patterns during vulnerable cycle phases. **Dosage & Administration** Not reported. The study measured quantity of dried cannabis flower consumed daily but did not specify standardized dosing units, THC/CBD concentrations, or administration routes beyond identifying "dried cannabis flower" as the primary form tracked. **Safety & Adverse Effects** Not reported. The study did not examine or document adverse effects, safety outcomes, or tolerability of cannabis use across the menstrual cycle. **Evidence Quality** This prospective study provides moderate-quality evidence with notable limitations. The use of PACTS represents a methodological advancement for menstrual cycle research, and prospective daily reporting reduces recall bias. However, the study enrolled only individuals with PMDs, limiting generalizability to general female cannabis users. Sample size and demographic characteristics were not fully detailed in the abstract. The 2-3 cycle follow-up duration is relatively brief. Findings require replication in larger, more diverse populations before clinical implementation. As a 2026 publication, peer-review status and full methodological details should be verified. The authors appropriately note that findings are preliminary and highlight need for replication before incorporation into clinical prevention and treatment strategies.

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