Psychological factors associated with substance use in adolescents

This thesis examines possible factors related to use of substances, with specific focus on psychological factors associated with increased risk of using illicit drugs. Thus, factors such as gender, personality traits, mental health status as well as family settings were investigated. Others factors also studied were use of tobacco, alcohol and illicit drugs, age of debut for substance use, subjective response to illicit drug use, attitudes towards drug use and future intentions of illicit drug use. An additional aim was to validate the health relevant personality inventory (HP5i) for adolescents. Participants were 3419 male and female senior high school students (18 years) in a cross-sectional study. Respondents filled out a self-administered questionnaire and the study was carried out in the participants’ schools. Study 1 showed that HP5i is a valid inventory and traits found to be associated with risk consumption of substances were mainly antagonism and impulsivity. Results from Study 2 showed that additional factors, such as problems within the rearing family, individual mental health problems and regular and excessive intake of legal substances, was associated with illicit drug use. Furthermore, significant associations between excessive use of illicit drugs, positive drug effects as well as intention of future drug use were found. In Study 3 groups of adolescents with different psychological profiles, based upon levels of impulsivity, depressive symptoms and positive drug effect were identified. Individuals characterised by high levels of the clustering variables reported severe use of substances and occurrence of other well known risk factors associated with substance use. Similar cluster profiles were also identified in a sample of adolescent in treatment for substance abuse. The findings from this thesis emphasize the fact that several psychological factors are associated with substance use in adolescence. Notable, the variable “positive drug effect” seems to be highly related to excessive illicit drug use and to intention of future drug use. Enhanced knowledge about factors related to substance use is important for the development of effective preventive and treatment strategies concerning adolescents’ substance use