This study aimed to describe the effects of cannabis on cumulative exposure across age and how age effects mid-term sobriety in people who are legally using cannabis. Using a repeated measures design this study examined exposure to cannabis, probabilistic electroencephalographic assessments from 479 people who were legal cannabis users. The participants, aged 16 and older, were recruited from an online youth North-American charity shop. A cannabis induction period was designed, with the first session serving as a non-cue baseline and all subsequent sessions used at the same dose to identify cannabis-dependent users and non-specific use at baseline. Cannabis dependence was assessed using the modified Adolescent Cannabis Dependence Questionnaire (M enable or disable cannabis dependence? depending on amount of cannabis exposure. Post-experiment probabilistic electroencephalographic assessments recorded over 30 minutes. Fifty-eight percent used cannabis at some time over the 4 weeks, using an average of 17.8.% THC and 29.53% CBD (i.e. 15.05% racemic cannabis product). The activities with the highest reported frequency of use were at home and at work or school. Sleep depended on age: relatively more the cannabis-dependent users reported out-of-bed activities (P<0.001) and younger users more in-bed activities (P=0.03) than the general legally using sample across the three age groups. Analyses of total trait anxiety scores, negative affect and phase III battery power changes with age showed increased anxiety and decreased negative affect with cannabis exposure in all three age groups. The use of cannabis and age were not unrelated to mid-way sobriety. Logistic regression