When an adolescent is addicted to a substance, he/or she will experience effects cognitively, in language areas, in physical development, in the role of the family, and in social development.

Cognitively, the adolescent will experience the extension of personal fable thinking, warped cognitions because of adolescent delusional system, blocked growth in the development of abstract thinking, illusions of adolescent accomplishment as a result of drug use, and less life experience causing interference in the growth of reasoning and thinking skills.

Effects of adolescent language skills will be impediments in recall, retrieval, and short-term memory, and if there is a weakening in academic performance than language skills may also be influenced; this scarcity of language skills may cause interference in academic and interpersonal functioning. If the adolescent has limited language skills then treatment may not benefit him/or her.

Physical development effects may include discomfort in sexual areas (if the individual uses marijuana at an early age then sexual development may be impaired), inaccurate sexual information, and inappropriate outlets for sexual energies.

Social development may be affected by the individual viewing drugs as his/or her primary relationship as opposed to other people. These individuals may develop a dependence on chemicals to ease social discomfort (inhibiting the growth of basic social skills for individuals of that age). Frequently these individuals will be in peer groups that are narcissistic, they may disregard the feelings of other people, and the adolescent may ignore the realities of society, such as rules, values, and morals.