Chapter 4 Research Methods for Studying Mental Disorders

Internal validity

the degree to which changes in the dependent variable are due solely to the effect of changes in the independent variable

Operational definitions

a concrete description of the variables that are being studied

Case study

an intensive study of one individual that relies on clinical data, such as observations, psychological tests, and historical and biographical information, Focuses on one person but may apply to others

Endophenotypes

measurable characteristics (neurochemical, endocrinological, neuroanatomical, cognitive, or neuropsychological) that can give clues regarding the specific genes involved in disorder, Heritable, seen in family members who do not have the disorder, and occur more frequently than in the general population

Genetic linkage study

studies that attempt to determine whether a disorder follows a genetic pattern

Epidemiological research

the study of the prevalence and distribution of mental disorders in a population, Used to determine the extent of mental disturbance in a population

Analogue study

an investigation that attempts to replicate or simulate, under controlled conditions, a situation that occurs in real life

Asymptomatic

without symptoms

Base rate

the rate of natural occurrence of a phenomenon in the population studied

Case study

an intensive study of one individual that relies on clinical data, such as observations, psychological tests, and historical and biographical information

Correlation

the extent to which variations in one variable are accompanied by increases or decreases in a second variable

Dependent variable

a variable that is expected to change when an independent variable is manipulated in a psychological context

Double blind design

an experimental design in which neither those helping with the experiment nor the participants are aware of experimental conditions

Evidence based practice

treatment decisions based on best current research combined with clinician judgement and client characteristics and needs

Evidence based therapies

treatment techniques that have strong research support

Experiment

a technique of scientific inquiry in which a prediction is made about 2 variables; the independent variable is then manipulated in a controlled situation, and changes in the dependent variable are measured

Experimental hypothesis

a prediction concerning how an independent variable will affect a dependent variable in an experiment

External validity

the degree to which findings of a particular study can be generalized to other groups or conditions

Field study

an investigative technique in which behaviors and events are observed and recorded in their natural environment

Hypothesis

a tentative explanation for certain facts or observations

Iatrogenic effects

unintended effects of an intervention-such as an unintended behavior resulting from a medication or a psychological technique used in treatment

Incidence

the number of new cases of a disorder that appear in an identified population within a specified time period

Independent variable

a variable or condition that an experimenter manipulates to determine its effect on a dependent variable

Longitudinal research

a research method that involves observing, assessing, or evaluating a group of people over a long period of time

Meta analysis

a statistical method in which researchers combine and analyze the results from numerous studies focused on the same of similar phenomena

Multiple baseline study

a single participant experimental design in which baselines on 2 or more behaviors or the same behavior in 2 or more settings are obtained prior to intervention

Penetrance

the proportion of individuals carrying a specific variant of a gene (allele of genotype) who also express the associated trait (phenotype)

Placebo

an ineffectual or sham treatment, such as an inactive substance, used as a control in an experimental study

Placebo effect

improvement produced by expectations of a positive treatment outcome

Scientific method

a method of inquiry that provides for the systematic collection of data, controlled observation, and testing of hypotheses

Single blind design

an experimental design in which only the participants are unaware of the purpose of the research

Single participant experiment

an experiment performed on a single individual in which some aspect of the person’s behavior is used as a control or baseline for comparison with future behaviors

Statistical significance

the likelihood that a research finding is not due to chance alone

Theory

a group of principles and hypotheses that together explain some aspect of a particular area of inquiry