ABSTRACT
This chapter presents the complexity of issues faced by clinicians while assessing and treating young people who misuse substances and have comorbid mental disorders. Treating mental illness and substance use disorders is a critical challenge due to the intricacy of the relationships between psychiatric symptoms and substance problems. The link between substance use and psychiatric symptoms was recognised by Trotter in 1804, who realised that drunkenness had a close affinity to ‘melancholia’, ‘mania’, ‘insania’ and ‘amentia’. Adolescence is a vulnerable developmental stage, when significant changes occur in a youth’s body, brain, environment and socialisation, which may increase vulnerability to substance use, development of addiction, and psychiatric disorders. A ‘primary’ psychiatric illness may lead to substance misuse and substance use disorder. Among adolescents, diagnostic criteria are not standardised even though there are developmental, psychological and social differences between adult and adolescent substance use and misuse.
