Tom Frijns

Demand-based estimates of total cannabis consumption rarely consider differences among different user types and variation across countries. To describe cannabis consumption patterns and estimate annual consumption for different user types across EU Member States, a web survey in Bulgaria, Czech Republic, Italy, the Netherlands, Portugal, Sweden and United Kingdom (England & Wales) collected data on cannabis use patterns from 3,922 persons who had consumed cannabis at least once in the past year. They were classified into four groups based on their number of use days in the past 12 months: infrequent users or chippers (<11 days), occasional users (11-50 days), regular users (51-250 days) and intensive users (>250 days). User type specific data on typical amounts consumed were matched with data on numbers of users per user type estimated from existing population surveys, taking differences in mode of consumption, age and gender into account. Estimates were supplemented with data from populations of problem users to compensate for under coverage. Results showed remarkably consistent differences among user groups across countries. Both the average number of units consumed per typical use day and the average amount of cannabis consumed per unit increased across user types of increasing frequency of use. In all countries except Portugal, intensive users formed the smallest group of cannabis users but were responsible for the largest part of total annual cannabis consumption. Annual cannabis consumption varied across countries but confidence intervals were wide. Results are compared with previous estimates and discussed in the context of improving estimation methods.

There is a widespread belief that weather affects mood. However, few studies have investigated this link, and even less is known about individual differences in people's responses to the weather. In the current study, we sought to identify weather reactivity types by linking self-reported daily mood across 30 days with objective weather data. We identified four distinct types among 497 adolescents and replicated these types among their mothers. The types were labeled Summer Lovers (better mood with warmer and sunnier weather), Unaffected (weak associations between weather and mood), Summer Haters (worse mood with warmer and sunnier weather), and Rain Haters (particularly bad mood on rainy days). In addition, intergenerational concordance effects were found for two of these types, suggesting that weather reactivity may run in the family. Overall, the large individual differences in how people's moods were affected by weather reconciles the discrepancy between the generally held beliefs that weather has a substantive effect on mood and findings from previous research indicating that effects of weather on mood are limited or absent.