Abnormal Psychology. William J. Ray

in low- and middle-income countries. Thus, family members and nonprofessionals are often involved in the treatment of mental disorders. It is critical that low-income countries use treatments that are both effective and available at low costs.

      Treatment research does exist that suggests that local communities can offer effective treatment for depression and schizophrenia. In low- and middle-income countries, these disorders often go untreated. This LENS focuses on depression, although similar positive results have been shown for schizophrenia, particularly in China. Depression is a common disorder throughout the world, so having effective treatments for depression worldwide is critical. Effective treatments are available for depression in terms of both psychotherapy and antidepressant medication. Both of these approaches can be delivered in a relatively inexpensive manner in low-income countries using community individuals with training in that one procedure. These trained individuals also have the advantage of understanding the culture in which the clients live. Not only does the treatment improve the individuals who have the disorder and their community, but it also has a positive effect on the economy by reducing days lost from work. A number of researchers have begun to evaluate the treatment of depression in low- and middle-income countries (Patel et al., 2007). Some examples of this research are shown in Table 3.1. To achieve the greatest scientific benefit, it is important that the participants in the experiment be assigned to groups using an RCT design. That is, the participants in the study must be randomly assigned to the treatment group.

      Thus, if the person’s family and community can be involved in the treatment, the results are more positive. Performing treatment studies in low- and middle- income countries is not only of benefit to the community but also helps the researchers to establish the generalizability of the treatment worldwide. Similar research with medical disorders in Africa by the Gates Foundation also suggests that successful interventions developed in low-income countries can be applied in low-income areas of the United States.

      Thought Question: What are the challenges and benefits involved in delivering and researching mental health treatment in low- and middle-income countries?

      Table 3.1

      RCT = Randomized controlled trial.

      Source: Reprinted from Patel et al., “Treatment and prevention of mental disorders in low-income and middle-income countries,” The Lancet, Vol. 370, 991–1005, Copyright 2007, with permission from Elsevier.

      Concept Check

       What are five factors critical to enabling sound inference in determining the relation between the IV and the DV in an experiment?

       Why is randomization important to selecting participants and assigning them to groups in an experimental study?

       What is a match subjects design? When would you use this design instead of a randomized study?

       What roles do the following hypotheses play in interpreting experimental results?Null hypothesisConfound hypothesisResearch hypothesis

      Other Types of Experimental Designs and Research Considerations

      In this section, I want to look at a few additional types of research that are used in the study of psychopathology. These include the study of a single person in an experimental manner, research that follows a number of individuals over a period of time, research that seeks to determine how frequently a disorder is present in a population, and research involving genetics. This section will conclude with a discussion of clinical and statistical significance and the importance of replication.

      Single-Subject Designs

      A single-subject design, also referred to as a small-N design, uses the data from one individual participant without averaging it as part of a group of participants. It is assumed that the topic under study is accurately reflected in the single individual and can be controlled appropriately. With this approach, statistical tests are typically replaced with graphical changes. For example, if you wanted to know if a child with autism would respond to a particular type of praise, you could determine this by having a condition in which you give praise and a baseline condition in which you do not. A stronger design, referred to as ABAB, would have a baseline condition (A) followed by the treatment condition (B). This is referred to as a reversal design. Such a design would appear as in Figure 3.9.

      single-subject design: also referred to as small-N design, an experiment that uses the data from one individual participant without averaging it as part of a group of participants

      Hersen and Bellack (1976) used a multiple-baseline design to demonstrate the effects of a treatment program for a schizophrenic patient. The patient made little contact with others, rarely engaged in conversation, and was compliant even to unreasonable requests. The treatment consisted of training in the development of assertiveness skills and skills for making contact with others. The measures taken over the baseline and treatment sessions were the amount of eye contact while talking, the amount of speaking without prolonged pauses, the number of requests made of another person, and the number of unreasonable requests not complied with. This design requires that baselines be taken for the four measures and that treatments be introduced at different sessions for each of the behaviors to be changed, while measurements of all behaviors are continued. This type of design helps us to determine whether the treatment was specific to a particular behavior (see Figure 3.10). Notice that the treatment was introduced at a different time (dotted vertical line) for each of the four targeted behaviors.

      Figure 3.9 ABAB Single-Subject Reversal Design

      Source: Dyer, Dunlap, & Winterling (1990).

      Figure 3.10 Probe Sessions During Baseline, Treatment, and Follow-Ups for Subject 1

      Source: Hersen & Bellack (1976, p. 243).

      In a longitudinal study on children with ADHD, a researcher may observe the same group of individuals for a period of years in order to detect changes over time.

      © iStockphoto.com/KatarzynaBialasiewicz

      Longitudinal Research

      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