Exploratory Prospective Study of Self-Titrated Medical Cannabis for Nonmotor Symptoms in Parkinson’s Disease

Background: Medical cannabis (MC) has emerged as a potential therapy for Parkinson’s disease (PD), targeting motor and nonmotor symptoms (NMS), such as pain, sleep disturbance, and urinary dysfunction. Cannabinoid receptors in central and peripheral systems, including the bladder, provide a mechanistic basis for symptom modulation. This study evaluated the feasibility, safety, and preliminary clinical effects of MC on NMS in PD within a real-world, regulated framework. Methods: In this single-center, open-label, prospective cohort, 68 patients with PD initiating MC were assessed at baseline and at 3 months using validated scales: the Non-Motor Symptoms Scale (NMSS), King’s Parkinson’s Disease Pain Scale (KPPS), PD Sleep Scale-2 (PDSS-2), PD Quality-of-Life Questionnaire-8 (PDQ-8), and International Prostate Symptom Score (IPSS), along with 2-day urinary diaries. Participants used either cannabis oil extract or inflorescence products with varying THC/CBD (Δ 9 -tetrahydrocannabinol/cannabidiol) ratios. Adverse events and withdrawals were recorded. Cannabinoid composition was analyzed via ultra-high-performance liquid chromatography and correlated with clinical outcomes. Results: Fifty participants (mean age 65.6 ± 11.0 years; 68% male) completed follow-up. MC use was associated with improvements in NMSS total (Δ 14.5, p = 0.001), PDSS-2 (Δ 5.9, p < 0.001), KPPS (Δ 8.1, p = 0.004), PDQ-8 (Δ 1.5, p = 0.040), and the NMSS urinary domain (Δ 2.1, p = 0.050). Nighttime urinary frequency decreased (median Δ 0.5, p = 0.016), while daytime parameters were unchanged. No correlations were found between cannabinoid composition or THC/CBD enrichment type and clinical response. The dropout rate was 26.5%, mainly due to loss to follow-up. Conclusions: Short-term, self-titrated MC was feasible and appeared generally well tolerated in this open-label setting, suggesting potential benefits for pain, sleep, and nocturnal urinary frequency in PD. These exploratory findings warrant randomized controlled trials focused on these domains and incorporating standardized dosing, pharmacokinetic monitoring, and predefined cognitive safety assessments to determine efficacy, safety, and optimal dosing.