Читать книгу Introduction to Abnormal Child and Adolescent Psychology - Robert Weis - Страница 46

Researchers conduct epidemiological studies to estimate the prevalence of psychological disorders in the general population. Prevalence refers to the percentage of individuals in a given population who have a medical or psychological condition. To estimate the prevalence of psychological disorders among children and adolescents, epidemiologists gather information from parents, teachers, and mental health professionals. Sometimes, epidemiologists also collect data from children and adolescents themselves, especially when questions deal with behaviors, thoughts, or feelings that might be hidden from parents (e.g., alcohol and other drug use, suicidal ideation). Epidemiologists can use this information to determine point prevalence, the percentage of youths with a disorder at a given point in time, and lifetime prevalence, the percentage of youths with a disorder at any point in their lifetime.

Sometimes, epidemiologists want to determine the likelihood that a child will develop a disorder in a given period of time. Incidence refers to the percentage of new cases of a disorder in a discrete period of time—usually 1 year. Because incidence only refers to new cases of a disorder, it is typically a much smaller number than prevalence. For example, the lifetime prevalence of autism spectrum disorder is approximately 1.8%; that is, roughly 1.8% of youths in the United States have been diagnosed with autism. However, the incidence of autism is approximately 0.3%; that is, in any given year, approximately 0.3% of children will be diagnosed with autism for the first time (Centers for Disease Control and Prevention, 2020c).

Determining the prevalence of children’s mental health problems is challenging for several reasons. First, there is no single agency that tracks the prevalence of mental disorders in children and adolescents. Instead, prevalence must be estimated using data from many individual studies conducted by different research teams (Costello & Angold, 2016).

Second, epidemiological studies use different methods to collect data, yielding slightly different results. For example, the National Health Interview Survey (NHIS) estimates the prevalence of childhood disorders by interviewing 12,000 parents each year. In contrast, the National Youth Risk Behavior Survey estimates behavior and substance use problems in adolescents by administering questionnaires to 16,000 high school students annually. These different research methods (e.g., interviewing parents vs. administering questionnaires to teens) can yield different findings. For example, parents are very good at reporting the severity of children’s disruptive behavior but are less accurate in estimating children’s difficulties with depression or use of alcohol. In contrast, adolescents may be more accurate reporters of their own mood and substance use, but they may underestimate the severity of their behavior problems (Kamphaus, Reynolds, & Dever, 2014; Stiffler & Dever, 2015).

Third, it is difficult to gather high-quality data. Many people do not want to participate in lengthy surveys, others do not understand the questions asked of them, and still others provide inaccurate information. Conducting large-scale interviews or surveys is also costly and time-consuming.

Despite these methodological obstacles, researchers have conducted several large epidemiological studies designed to estimate the prevalence of childhood disorders. Collectively, these studies include data from tens of thousands of children and their caregivers, using a variety of research strategies. Altogether, these data suggest that 13% to 15% of youths experience a psychological disorder in any given year. Slightly more than 20% of youths experience a disorder at some point before adulthood (Perou et al., 2016).

Recent data indicate that the overall prevalence of children’s mental health problems is on the rise. For example, in the past decade, there has been a 24% increase in the number of children receiving mental health or substance abuse treatment in the United States. The number of youths prescribed medication to treat psychological disorders has also increased approximately 28% during that same time (Visser, Danielson, & Bitsko, 2014). Finally, the rate of hospital admissions for children with psychological disorders, such as depression, has increased 80% in the past 20 years (Pfuntner, Wier, & Stocks, 2013).

Table 1.2 shows the prevalence of specific mental disorders among children and adolescents in the United States. As you might suspect, ADHD is the most common condition. Almost 9% of youths are diagnosed with this disorder at some point before adulthood. Anxiety disorders, such as separation anxiety disorder or social phobia, are also relatively common. Certain conditions, such as autism, are more common than previously thought. Approximately 1 in 59 children will develop this serious condition (Centers for Disease Control and Prevention, 2020c). Other problems such as eating disorders and schizophrenia are relatively rare in children.

Table 1.2

Note: This table shows the median percentage of youths with each disorder from the following datasets (for 2013–2020): Centers for Disease Control and Prevention, National Comorbidity Survey Replication–Adolescent Supplement, National Health Interview Survey, National Health and Nutrition Examination Survey, National Survey of Children’s Health, National Survey on Drug Use and Health, and the National Youth Risk Behavior Survey.