Another useful model for understanding the nature and extent of drug-related difficulties considers the actual nature of the difficulties experienced. Thorley's model looks at patterns of use and related problems whereas the Four L's model, (adapted by Roizen) considers the impact of drug use on four major spheres on a young person's life. These are:
- Liver: Anything to do with a person's health – either physical, psychological or emotional health problems
- Lover: Problems associated with a person's relationships, family, friends, children, lovers etc.
- Lifestyle/Livelihood: Problems which relate accommodation, work, finances, education, recreation etc.
- Legal: Any problems associated with the law – either criminal or civil proceedings.