The prevalence of SUDs increases with age through young adulthood when both SUDs and substance use peak. Data from the National Survey on Drug Use and Health indicate that very few youth (less than 3%) met criteria for any past-year SUD prior to age 14. SUDs increased steadily from age 14 (7%) to age 21 (25%), with peak prevalence occurring in the 20s. Among 12- to 17-year-olds, 9% met criteria for a past-year DSM-IV SUD abuse or dependence diagnosis, 6% had an alcohol-related diagnosis, and 4% had a cannabis diagnosis; 2% met criteria for use of both alcohol and at least one illicit substance. However, other studies show considerable variation of rates, especially when sampling different-aged adolescents. Recent national survey data indicate little to no difference in rates of past-year SUD prevalence by gender for alcohol or illicit drugs. Similar to ethnic differences in the prevalence of substance use, larger proportions of Caucasian and Hispanic youth aged 12 to 17 years met criteria for a past-year DSM-IV alcohol or drug diagnosis than African Americans (10%, 10%, and 6%, respectively), although American Indian adolescents had the highest proportion of alcohol or other drug diagnoses (20%).

According to the National Survey on Drug Use and Health, the rates of current illicit drug use among youths aged 12 to 17 were 11.6% in 2002 and 9.9% in 2005. In 2005, 9.9% of youths aged 12 to 17 were current illicit drug users: 6.8% used marijuana, 3.3% used prescriptiontype drugs nonmedically, 1.2% used inhalants, 0.8% used hallucinogens, and 0.6% used cocaine. In 2008, adolescents in the United States continued to show a gradual decline in their use of certain drugs, especially stimulants including amphetamines, methamphetamine, crystal methamphetamine, cocaine, and crack, according to the Monitoring the Future (MTF) annual national survey of the US students in 8th, 10th, and 12th grades.

Only a small percentage of adolescents with SUDs actually receive treatment. Among youths aged 12 to 17, there were 1.3 million (4.9%) who needed treatment for an illicit drug use problem in 2005. Of this group, only 142,000 received treatment at a specialty facility, that is, 11.3% of youths aged 12 to 17 who needed treatment, leaving 1.1 million youths who needed such treatment but did not receive it. Among 12- to 17-year-olds in publicly funded programs, most were referred by the criminal justice system, with smaller proportions referred by schools or family; rates of self-referral to treatment begin to increase in young adulthood.

In order to screen large numbers of youth, clinicians and others such as school professionals, mental health professionals, and primary health care professionals often rely on the use of screening instruments. The two alternative approaches to screening involve (1) specific screening of substance use and related behaviors, focusing on this behavior alone, and (2) screening for SUD as part of a multidomain screen that includes mental health problems and high-risk behaviors. In a primary care setting, questions for all youth about substance use follow a general inquiry about health behaviors and should include questions about cigarette, alcohol, and other substance use. In settings such as child welfare, mental health, or juvenile justice, the high-risk status is sufficient to require screening of each adolescent. Primary health care staff (e.g., physicians and nurses) may use a brief series of questions to screen for substance-use problems. Although specific interview questions with established validity, such as the CRAFFT (see Table 6-3), are often sufficient, many clinicians or other relevant professionals use other specific screening instruments.

Professionals need to decide what screening threshold will trigger a comprehensive assessment. The CRAFFT has a threshold of two positive items. Other factors, such as past history of substance use, high-risk behaviors, and moderate to severe high-risk status, may prompt such a referral even in the absence of an adolescent report of regular use or consequences.

The assessment process is used to identify those individuals who have an SUD and whether they meet criteria for a DSM-IV diagnosis. Substance-using behaviors, the pattern of use, and any consequences of use are also discussed. The results of the comprehensive assessment should also identify which adolescents require treatment, the level of treatment needed, and other problems that may need intervention. Many screening and comprehensive assessment instruments follow the Domain Model of assessment, shown in Table 6-4, that provides a review of the primary domains of adolescent functioning, including substance-use behaviors, psychiatric and behavioral problems, school and occupational functioning, family functioning, social competency and peer relations, and leisure and recreation.

As primary health care professionals often have a long-standing relationship with the adolescent and his or her family, they are in an optimal position to track developmental risk factors that may lead to substance use and SUDs as well as identify these problems. Screening through the use of the CRAFFT allows for screening through a conversational format of a series of questions. Some primary care professionals may elect to proceed to a more comprehensive substance-use history, inquiring about age of onset, duration, frequency, and route of ingestion for each individual drug including alcohol, tobacco, illicit drugs, inhalants, over-the-counter medications,
and prescription drugs such as benzodiazepines, opiates, and stimulants. Additional questions should cover negative consequences as well as attempts and motivation to control use or quit. Questions detailing the context of use include the setting of use (time and place), whether the adolescent uses alone or with peers, and the attitudes of these peers about substance use. Variability in quantity and frequency of adolescent substance use is often great. The adolescent may report periods of abstinence as well as periods of rapid acceleration of use and heavy use of particular agents. A timeline drug chart or calendar is often useful to allow the adolescent to report quantity, frequency, and variability data across time with important dates, holidays, and other time cues as a guide. Additional substance-use-related information includes attitudes, expectancies of use, and motivation(s) or perceived benefits to use. Assessment of substance-use behavior may follow a functional analysis of use to determine usual antecedents to use and consequences of use. Such an analysis may allow a more specific targeting of relevant antecedents during treatment. Along with specific attitudes and beliefs about substance use, the interviewer may also inquire about the adolescent’s values and attitudes in general.