Exclusive Therapeutic Use of Cannabis in a Large Sample of Daily Cannabis Users in France: A Cross-Sectional Survey.

Many cannabis users report therapeutic benefits from cannabis consumption, even when not recommended by a physician. To date, few data on therapeutic users of cannabis in France are available. Using a cross-sectional survey held in 2020, we collected sociodemographic, health and substance use data from 4150 daily cannabis users in France. We used multivariable logistic regression to assess factors associated with exclusive therapeutic use of cannabis. Approximately 10% (n = 453) of the participants reported using cannabis exclusively for therapeutic purposes. Exclusive therapeutic users of cannabis differed from non-exclusive (i.e. recreational and mixed) users, especially regarding age (aOR [95%CI] = 1.01 [1.00-1.02]), employment (aOR = 0.61 [0.47-0.79]), urban area of residence (aOR = 0.75 [0.60-0.94]), physical (aOR = 2.95 [2.34-3.70]) and mental health condition (aOR = 2.63 [1.99-3.49]), mode of cannabis administration (non-smoked, aOR = 1.89 [1.22-2.95); smoked with little tobacco, aOR = 1.39 [1.09-1.76]), frequency of cannabis use (aOR = 1.04 [1.01-1.06]), home cultivation (aOR = 1.56 [1.13-2.15]), at-ridsk alcohol use (aOR = 0.68 [0.54-0.84]), and previous-month opiate use (aOR = 1.67 [1.22-2.30]). A greater understanding of the distinct profiles of regular cannabis users could inform harm reduction strategies and care access for this population. Further studies are needed to better understand the boundaries between therapeutic and recreational use.

Changes in cannabis use and associated correlates during France's first COVID-19 lockdown in daily cannabis users: results from a large community-based online survey.

BACKGROUND: Lockdown measures during the first wave of the COVID-19 pandemic in France led to serious public health concerns over people who use illicit drugs, especially in terms of mental health. We assessed changes in cannabis use during the first lockdown in France among daily cannabis users and associated correlates. METHODS: CANNAVID is a French, national, cross-sectional web-based survey, conducted from 17 April to 11 May 2020. Daily cannabis users aged ≥ 18 years and living in France were invited to participate through advertisements. Respondents completed an ad hoc questionnaire on a dedicated online platform. We analyzed changes in cannabis use during the first lockdown (i.e., stopped, decreased, unchanged, or increased) and performed a multinomial logistic regression analysis to evaluate correlates of these changes. RESULTS: Of the 4019 participants, 74.0% were men. Median age was 27 years (interquartile range: 22-37). With regard to cannabis use, 293 (7.3%) persons stopped, 1153 (28.7%) decreased, 1146 (28.5%) did not change, and 1427 (35.5%) increased their use during the lockdown. A multinomial logistic regression model revealed several sociodemographic, behavioral and health-related factors associated with changes in cannabis use. Compared with participants with an unchanged level of cannabis use during the lockdown, those who increased and those who stopped cannabis use were more likely to have increased tobacco and alcohol use and to have experienced depression and sleep disorders intensification. Those who stopped cannabis use were also more likely to have increased benzodiazepine use and to have experienced pain increase during lockdown. CONCLUSIONS: France's first COVID-19-related lockdown had a differential impact on daily cannabis users' consumption patterns. Most study respondents reported changes to their cannabis consumption pattern. Those who reported a stable cannabis use were more likely to report fewer negative changes. Specific interventions are needed for this population, as well as research to assess the long-term impacts of these changes.

Limits of imaging-system simplification using cubic mask wavefront coding.

Increasing the space-bandwidth product of an imaging system will lead to a complex and expensive optical system. Techniques exist to simplify imaging systems. We propose the use of a hybrid imaging system using pupil phase modulation. Based on the reconstructed image's mean-squared error, we compute how this error is affected under various third-order aberrations. We determine the best cubic phase-mask parameter and study the impact of the orientation of the coma and astigmatism, as we have in a real optical system (from 0 to 2π). We then compute how the reconstructed image's quality varies by adding defocus-related aberrations (defocus and/or field curvature). Based on our analysis, we determine the limits of a hybrid imaging system using a cubic phase mask to develop simplified imaging systems. We conclude that the simplified lens design can be corrected if its aberrations are limited to 1 lambda of coma, astigmatism, and spherical aberrations and less than 1 lambda of field curvature or defocus.