UK registry study found early PTSD score improvements, then a plateau

RATIONALE: Post-traumatic stress disorder (PTSD) is characterised by persistent psychological symptoms following exposure to trauma. Cannabis-based medicinal products (CBMPs) have promising therapeutic potential. However, there is a paucity of long-term studies investigating their use. OBJECTIVES: This prospective case series aimed to assess changes in patient-reported outcome measures (PROMs) and the prevalence of adverse events in patients prescribed CBMPs for PTSD. METHODS: Patients enrolled on the United Kingdom Medical Cannabis Registry for PTSD were included. Changes in PROMs (Impact of Events Scale-Revised (IES-R), Generalised Anxiety Disorder-7 (GAD-7), Single-Item Sleep Quality Scale (SQS) and EuroQol 5-Dimension 5-Level questionnaire (EQ-5D-5​L)) were assessed from baseline up to 24 months. RESULTS: In total, 446 patients were included, of which 75.11% (n = 335) were already using cannabis before starting treatment. Mean IES-R, GAD-7, SQS and EQ-5D-5​L scores improved relative to baseline at all follow-up times (p < 0.001). At 24 months, 64.57% (n = 288) of IES-R data were imputed. The mean IES-R fell from 59.58 ± 15.93 at baseline to 36.91 ± 18.56 at 24 months, with 55.38% (n = 247) of patients continuing to meet the DSM-IV threshold for PTSD at 24 months. Seventy-five patients (16.82%) reported at least one adverse event. Of 578 events, 83 (14.36%) were severe, and 2 (0.35%) life-threatening or disabling. CONCLUSION: In this uncontrolled case series, CBMP treatment was associated with improvements in mean PTSD symptom, anxiety, sleep, and health-related quality of life scores. However, the improvement was concentrated within the first month and then plateaued. The observational design, high attrition, and reliance on imputed data preclude any inference of efficacy or causality.