[Comorbidity between attention deficit/hyperactivity disorder and substance use disorders: evidence from animal models].

OBJECTIVE To describe some recent theories regarding the comorbidity between attention deficit/hyperactivity disorder and substance use disorders and discuss the utility of using spontaneously hypertensive rats (an animal model of attention deficit/hyperactivity disorder) for the study of attention deficit/hyperactivity disorder and substance use disorders comorbidity. METHOD We compiled the main results of studies investigating the behavioral effects of drugs of abuse in spontaneously hypertensive rats. RESULTS AND DISCUSSION Spontaneously hypertensive rats, in addition to expressing the main features of attention deficit/hyperactivity disorder (impulsivity, hyperactivity, and attention deficit), appear to be more sensitive to psychostimulants, cannabinoids, and opioids and drink large amounts of alcohol. Repeated treatment of spontaneously hypertensive rats with methylphenidate (a first-choice drug for the treatment of attention deficit/hyperactivity disorder) or exposure to an enriched environment during adolescence resulted in an increase or decrease, respectively, in alcohol consumption in adulthood. These results suggest that environmental factors can either favor or confer resistance to attention deficit/hyperactivity disorder and substance use disorders comorbidity. Although research is at the very early stage in this field, spontaneously hypertensive rats appear to be a useful animal model for the study of attention deficit/hyperactivity disorder and substance use disorders comorbidity.