‘Social cognition’ refers to multiple psychological processes underlying human interaction, including understanding that other individuals are also experiencing complex emotions (known as ‘Theory of Mind’), and the ability to recognise these emotions (for example, through facial expressions). Long-term drug users often have problems with social cognition. Users of cannabis, tobacco, alcohol, and other drugs have difficulties recognising others’ emotional expressions, and have difficulty understanding with Theory of Mind. However, it’s not clear if using drugs results in these problems, or if people who have poor social cognition to begin with are more prone to use drugs. For example, people with poor social cognition may use drugs to improve their interactions with others. The use of drugs to help with a psychological problem is known as ‘self-medication’, and there is some evidence for this. For example, heavy smokers only seem to have difficulty with social cognition when they stop smoking. Additionally, many individuals’ suffering from mental health problems believe that their drug use helps to alleviate their symptoms (for example, by reducing their anxiety). Many mental health disorders also include problems with social cognition and are linked to high rates of drug dependence. For this reason, we previously studied the relationship of poor social cognition in childhood (age 7) with teenage drug use (age 17). Interestingly, we found that poor social cognition in childhood (particularly recognising emotional expression) was related to decreased teenage drug use. The current study aims to explore the relationship between childhood mental health problems (age 7) and teenage drug use (age 17). By examining childhood mental health problems separately from social cognition, we can explore if these two are related to teenage drug use in similar or different ways. Our results may be useful for identification of targets for early intervention.