The percentage of people with mental retardation in the general population is estimated at about 2.3%, with adolescence (15–20 years) constituting the development period during which a peak in rates of mental retardation is observed. The increased prevalence of adolescence may be explained from the fact that the specified requirements of the school initially, and society later, inevitably lead to comparative evaluation of the teen with mental retardation in relation to peers, thus making mental retardation more apparent. Adolescents with mental retardation face a number of physical and psychological needs which are not often distinguishable and as a consequence undergo the deterioration of their already burdened quality of life. In particular, mental health problems occur 3 to 4 times more often in adolescents with mental retardation compared with adolescents of the general population. This review presents the most recent epidemiological findings regarding the correlation between behavioral disorders, substance use and the possible comorbidity in adolescents with intellectual disability, both at community level and residential care level. Epidemiological data indicate that behavioral disorders are among the most common types of psychopathology in mentally retarded adolescents with the severity and symptoms varying depending on the personal characteristics of each adolescent. Regarding substance use, the available data show that the rates of substance use (alcohol, smoking, illicit drugs) are lower in this specific population group but the differences over the last years tend to be eliminated. Finally, according to the few surveys that were examined referring to the comorbidity of behavioral disorders and substance use in adolescents with intellectual disability, the results were contradictory. Specifically, while behavioral disorders continued to be one of the most common types of psychopathology, the related substances disorders indicated lower rates compared to normal intelligence adolescents with behavioral disorders. Risk factors that increase the chances of developing either simple or more complicated types of psychopathology in adolescents with mental retardation have been found to be based on individual, family and social levels. On the other hand, the individual characteristics of adolescents (intellectual level, attention capacity, understandable linguistic expression, overall progress until adolescence), the existence of a supportive family environment and the presence of social support and awareness through the creation of special counseling, education and medical services, are the most important protective factors which contribute to the prevention of several forms of psychopathology in adolescents with mental retardation. For the writing of the literature review, the following electronic databases were used: PubMed, Scopus, Psycinfo, Cochrane Library, Web of Science and Google Scholar. The key words used were: Intellectual Disability, Behavioral disorders, Adolescents, Mental Retardation, Learning disabilities, Developmental Disabilities, Disruptive behaviour disorders, Conduct disorder, Substance Abuse, Substance Misuse, Oppositional defiant disorder, Alcohol and illicit drug use, Smoking Use, Young people, Teenagers, Youths.

Key words: Behavioral disorders, substance abuse, mental retardation, comorbidity, adolescents.

E.C. Papachristou, D.K. Anagnostopoulos (page 139) - Full article (Greek)