Cannabis is the most commonly used illicit drug worldwide, with use particularly prevalent in adolescents. The number of under-18’s in treatment for cannabis as a primary problem in the UK in 2019-2020 was 11,136, 78% of all treatment entrants in this age group. Whilst this demonstrates a current clear demand for treatment of cannabis problems, the majority of people with cannabis problems do not seek out professional treatment. Further, current psychosocial treatment options lack data on their long-term efficacy, and there are no approved pharmacological treatments. One approach to tackle the global burden of cannabis use disorder (CUD) is to develop early targeted interventions, directed towards reducing the incidence of CUD. Identifying key variables that are associated with development of cannabis problems could help to ascertain which groups are most at risk. Previous research in adolescent and adult populations indicates that cannabis use profile, mental health problems and other drug use are all associated with increased risk of sustained problems related to cannabis use, compared to those with stable-low risk of cannabis problems. However, these studies either did not investigate childhood risk factors, or only assessed these retrospectively, and did not collect data specifically prior to cannabis initiation. This project aims to identify distinct trajectories of cannabis problems, and assess whether mental health and cognition in childhood (8-10 years old), prior to onset of cannabis use, represent potential modifiable risk factors for likelihood of experiencing problems with cannabis use, in order to inform early interventions to potentially reduce the incidence of cannabis problems.