1. Reasons for skepticism (p. 105) Research, such as gentle touch, frequently describe research findings as conclusive, but after use of the scientific method, these claims are often proven unfounded. Firm scientific information requires the replication of results, good research methods, and a skeptical attitude. Initial reports that a specific gene, A1 allele of DRD2, for alcoholism existed were questioned when subsequent studies found no difference in the prevalence of the gene in controls and samples of alcoholics and when equal or greater numbers of nonalcoholic clinical populations showed the alcoholism gene.
2. The scientific method in clinical research (p. 106) The most general characteristic of science is its potential for self-correction. Hypotheses must be clearly stated and variables given definitions. Recent studies of child sexual abuse illustrate the range of definitions used. Measures must show reliability and validity. Appropriate comparison frequencies for a phenomenon (base rates) should be considered. For instance, if eating problems and child abuse are both commonly occurring events but one is unaware of this, one could mistakenly conclude that abuse causes eating problems. Finally, results should be evaluated in terms of both statistical significance (whether the results were due to a factor other than chance) and clinical significance (whether the results have clinical value). In large-sample studies, statistically significant differences are sometimes clinically meaningless.
3. Experiments (p. 112) Experiments include experimental and control groups. Only the experimental group participants are exposed to the independent variable (the possible cause of behavior the experimenter manipulates). Measures of the dependent variable (the behavior believed to be controlled by the independent variable) are taken for participants in both groups. Placebo groups can be included to rule out the possibility that participants expectations alter their behavior in the experimental group. Experimenter expectations can also be controlled by making the clinicians in a study blind (uninformed) as to the experimenters hypothesis. To reduce the impact of both experimenter and participant expectations, there are double-blind designs where neither the individual working directly with the participant nor the participant is aware of who is in the experimental group. When changes in the dependent variable can unambiguously be attributed to the changes in the independent variable, a study is said to have internal validity. When results of a study can be generalized to other populations or situations, the study is said to have external validity.
4. Correlations (p. 115) Correlations measure the degree to which changes in one variable are associated with changes in another variable. Statistically, these associations, correlation coefficients, are symbolized by r, which ranges from -1.00 to +1.00. Even if a correlational study shows a strong association, it is often difficult to determine whether Variable A caused changes in Variable B, Variable B caused changes in Variable A, or some third variable affected the other two.
5. Analogue studies and field studies (p. 119) When the study of real-life situations is impractical or unethical, analogue studies are conducted in simulated, but controlled, circumstances. When analogue studies are too contrived, observations can be made in the real-life situation in what is called a field study. These are limited research strategies because they cannot determine the direction of causality and they introduce the potential for observers influencing behavior.
6. Single-participant studies (p. 120) Although most research methods are aimed at making general statements about behavior and, therefore, use groups of people (the nomothetic orientation), in-depth studies are sometimes done on individuals (the idiographic orientation). The case study is used extensively by clinicians, and although it lacks control and objectivity, and thus cannot be used to show cause-and-effect relationships, it does examine and analyze conditions over a period of time. The single-participant study measures an individual's behavior over time. It observes changes that occur after some behavior modification has been applied. A second type of single-participant experiment obtains baselines on two or more behaviors and introduces the same intervention with each to see if the behaviors change with the intervention.
7. Biological research strategies (p. 122) Genetic linkage studies determine if a disorder follows a genetic pattern by identifying the family members of a person with a disorder (proband) who also suffer from it. Biological marker studies identify a biological characteristic (for example, blood flow patterns or brain size) that is associated with a disorder in family members of a proband.
   Researchers must be on guard for iatrogenic effectsthose negative effects brought on by treatment. For example, traumatic events recalled during hypnosis may be a function of hypnotic suggestion more than accurate recollection. When a person carries a gene for a characteristic but fails to show the characteristic, there is incomplete penetrance. Symptoms that are distinctive for a disorder are considered pathognomonic. Finally, when clinical researchers use biological challenge tests, they observe for changes in behavior when chemicals (foods, allergens, or drugs) are introduced and for those behaviors to disappear when the chemical is absent.
8. Epidemiological and other forms of research (p. 124) A variety of research types, including survey research, longitudinal research, historical research, twin studies treatment outcome and treatment process studies, and program evaluation can use experimental, correlational, or single-subject methods. An important type of research is epidemiological research, which examines the rate and distribution of mental disorders. It can reveal the rate of new cases (incidence) or the total rate of cases (prevalence) as well as risk factors associated with the disorder.
9. Ethical issues in research (p. 125) The scientific method can be abused and misused. The American Psychological Association has adopted the principle that the likely benefits of research must outweigh the risk or discomfort to its participants. Deception should be used only when alternatives are not possible. Only when alternatives are unavailable should animals be used as subjects, and then they should be treated in humane ways. Guidelines for research sensitive to minority ethnic and religious groups are also in place.