Читать книгу Abnormal Psychology - William J. Ray - Страница 134

A longitudinal design allows the researcher to follow a specific group of individuals across a period of time to document any changes that take place during that period. For example, one study followed children diagnosed with attention deficit/hyperactivity disorder (ADHD) for 9 years and noted changes in specific symptoms (Lahey & Willcutt, 2010). By comparing the children with ADHD to children without the disorder, it was possible to determine normal developmental changes as opposed to changes related to ADHD itself. These researchers were also interested in knowing if ADHD symptoms in year 1 were predictive of symptoms and teacher ratings in later years, which they were. Another study asked if living in difficult neighborhoods and being maltreated as a child would predict drug use in middle adulthood, which it did (Chauhan & Widom, 2012).

longitudinal design: a research technique that allows the researcher to follow a specific group of individuals across a period of time to document any changes that take place

There are a number of advantages to using a longitudinal design. First, it allows us to study the natural history of the development of a mental disorder in comparison with a similar group without the disorder. Second, we can note when and in what manner the changes in the disorder take place. Some disorders, such as schizophrenia and bipolar disorder, tend to have an abrupt onset. Third, longitudinal designs are particularly useful for studying prevention or treatment programs regarding longer-term changes. Of course, the disadvantage of these designs is that they require a significant period of time to complete the study.