Psychopathology can be thought of as the expression of mental impairment in the form of psychological signs and symptoms. Specific disorders subsumed under psychopathology, while having specific signs and symptoms, have as their common thread a significant impairment in mental functioning that causes distress or disability. However, no one sign or symptom is usually sufficient to describe a given mental disorder. Rather, a cluster of related signs and symptoms are necessary that are associated with the distress or disability that is presented. The acquisition of reliable, accurate accounts of those critical features of psychopathology is the goal of any assessment of psychopathology.
Widely known criteria for the various forms of psychopathology appear in the American Psychiatric Association’s Diagnostic and Statistical Manual for Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) and the World Health Organization’s International Classification of Diseases, Clinical Modification (ICD-10-CM). The assessment of psychopathology may at first appear to involve a rather straightforward appraisal of the relative “fit” of these criteria to the particular history and behavioral repertoire of the individual being assessed. This view suggests that appraisal involves little more than decisions about whether one or more sets of these criteria are represented in the information gathered about an individual. If so, the diagnosis (i.e., form of psychopathology) associated with those criteria is assigned to represent the individual’s psychological problem(s).
However, the reality is more complicated than the above suggests. Before psychologists can assess the fit of any set of criteria to an individual, they must make a number of decisions regarding the assessment process itself. These include an evaluation of their ability to accurately judge the presence or absence, quality, and quantity of the criteria. In other words, psychologists must evaluate the reliability, validity, and usefulness of the information to be used in assessing the criteria and the context in which the information will be used before the information is accepted for use. Additionally, the perspective taken, for instance, whether the focus is on direct behavioral examples or inferred (i.e., not directly observable) processes, must be taken into account. The ideas and biases of the assessor must be carefully considered. Finally, the information, be it a diagnosis or behavioral description, must be accurately conveyed to the appropriate referring source to actually aid the person being assessed. This has led to the development of a wide range of assessment tools that include unstructured and structured interviews, self-report inventories, measures of cognition, projective techniques, behavioral descriptors, and many more.
The Clinical interview
The interview is one of the most basic components of all forms of psychological assessment, including the assessment of psychopathology. Interview formats vary across a continuum from unstructured to highly structured. The unstructured interview is what people most often think about when describing the interview process, though unstructured is probably a misnomer. It is essentially a data-gathering process in which information is most often collected face-to-face with a client through an interactive series of questions and answers that can vary greatly from client to client. Typically, questioning follows a format beginning with open-ended questions that can provide information about the content provided, but also about the process the client uses to respond. Questions gradually become more and more close ended during the interview to help fill in needed specific information about the client. The unstructured interview is also used to obtain information from other sources, such as family members or others who can comment on the client’s actions.
Whether structured or unstructured, most diagnostic interviews are designed to obtain essential information about many aspects of the person’s life situation, such as those listed in Table 1. There are a number of advantages of unstructured interviews, including their flexibility in both the content and the range of information to be sampled. When the psychologist is not limited to what may be asked, or in what manner questions may be asked, important information can be followed up as it unfolds during the interview. Another advantage is the “ecological validity” of the behaviors sampled during the observation of and interaction with the client. Ecological validity pertains to how well the information gathered truly assesses what is important to the client’s functioning in the “real” world. Information is more likely to be individualized and specific to the client during an unstructured, and thus unhampered, interview. Disadvantages can include the potential for uneven and incomplete collection of necessary information by the clinician, as for example when a psychologist spends a great deal of time evaluating reports of depression and fails to fully assess other issues, such as anxiety. Later, comparing only this incomplete set of information with the specific criteria used to make a differential diagnosis can compound an oversight such as this. Nevertheless, a wealth of information can be gathered due to the flexibility of the unstructured clinical interview. Through focused follow-up and probing, many symptom criteria can be directly screened and explored with the client or with collateral sources.
In contrast, structured interviews are those that use a specific set of questions to obtain information that is directly related to a set of criteria of particular interest. Structured interviews were developed to reduce the elements of clinical judgment inherent in unstructured interviews. Structured interviews permit the generation of “objective” ratings. This has several advantages. It allows comparisons between cases on essentially the same information. Furthermore, having objective ratings allows psychometric testing of the interview itself in terms of assessing the interview’s reliability and validity. A number of structured interviews varying from the global to the specific have been developed for use in diagnosis.
An early, structured-interview strategy was developed by John P. Feighner and colleagues in 1972 to identify the primary psychiatric disorders then described in the Diagnostic and Statistical Manual (DSM) of the American Psychiatric Association. In the late 1970s, an influential group of researchers including Robert Spitzer and Jean Endicott altered and expanded these criteria to develop the Research Diagnostic Criteria (RDC). This work, in turn, formed the basis for the Schedule for Affective Disorders and Schizophrenia, or SADS. Over the years, the SADS became one of the most widely used and respected structured interviews for diagnosis, and it has been particularly useful in research settings where consistency in diagnosis is essential. The DSM has undergone several revisions and these structured interviews have been modified to reflect the changing criteria for the various forms of psychopathology, leading most recently to the Structured Clinical Interview for the DSM (SCID) and its revisions. Somewhat in parallel development, the Diagnostic Interview Schedule (DIS) is based on a combined set of criteria from the DSM and RDC and it allows diagnosis based on either criteria set.
What these structured interviews all have in common is their dependence on a priori selection criteria for making decisions regarding diagnoses. They differ in their specificity and breadth, and in the amount of clinical judgment and expertise needed to use them effectively. The DIS is very structured, containing very specific questions, and can be used with a high degree of reliability by trained nonprofessionals. The SADS is semistructured and it requires the extensive use of clinical judgment in making diagnostic decisions. Typically, only experienced mental health professionals use it. The SCID falls somewhere between these extremes, although it is best used by a trained clinician.
Structured and semistructured interviews are currently underutilized in the clinical assessment of psychopathology. This is attributable, in part, to the fact that they were originally developed for use in research. In addition, many psychologists have not been specifically trained in their use. However, the increased reliability of the newer forms of structured interview suggests that psychologists would benefit from incorporating them into their assessment tool kit.
Instruments Used in Assessing Psychopathology
Many tests have been used to gather information about clients’ psychological and mental health other than direct interviews. Tests specific to addressing the presence and severity of psychopathology include both projective methods and objective self-report inventories.
The most common projective techniques in use today were actually developed many years ago. They include the Rorschach Inkblot test, developed in 1921, the Thematic Apperception Test, which dates from 1943, and a number of projective drawing techniques.
The Rorschach Inkblot Test.
The Rorschach Inkblot test is a 10-plate set of bisymmetrical inkblots. By their nature, the inkblots provide an ambiguous set of stimuli to the client. For each individual plate, the clients are simply asked to tell the assessor what the inkblots remind them of. Thus, without further instruction, clients are placed in a position that necessitates the use of their own personal perceptual experiences to place an organizational structure and context onto these otherwise ambiguous stimuli. In this way, the organization of the material becomes a behavioral example of the way clients approach and organize the world with which they interact.
The Rorschach has been used extensively and many categories of response type have been developed, particularly regarding the determinants of what goes into individual percepts. These include the use of form, color, symmetry, and even textural cues. The core elements needed to interpret any Rorschach response are what the response is, where it is located, and why or what makes it look that way. The interpretation of these elements as they represent organizational strategies and methods has been used to provide information about people’s interpersonal style, motivation, emotional processes, and even their cognitive abilities. While controversial because of arguments regarding its reliability and validity, the Rorschach is still commonly used by many clinicians. Effective use of the Rorschach requires extensive training in its administration and, in particular, in the interpretation of responses to the Rorschach materials.
Thematic Apperception Test.
The Thematic Apperception Test (TAT) was originally developed in conjunction with Henry Murray’s need-press theory of personality. It is made up of a series of pictures that show characters in a variety of ambiguous situations. Examinees are instructed to make up an oral story about each picture. The rationale underlying the TAT is that the stories told by examinees in their search for some meaning in the ambiguous pictures represent projections of the examinees’ past experiences and present needs. Thus, somewhat similar to the Rorschach, the test uses ambiguous stimuli to elicit samples of the ways the examinee organizes the world. Unlike the Rorschach, the TAT makes use of a sample of specifically focused instructions that are repetitive across picture stimuli. Thus the examiner can elicit samples of similar or “thematic” situations by selecting particular subsets of cards to present. The examiner follows an interpretive strategy that focuses on the characters and settings in the stories told by the examinee, as they are likely to reflect the examinee’s placement of self into them. The protocol data thus elicited are presumed to provide a representation of personality content and character structure.
Projective Drawing Tests.
Projective drawing techniques used in the assessment of psychopathology are generally one of two types, Draw-A-Person or Draw-A-House. In both, clients are asked to draw freehand one or more pictures of themselves, significant others, their family, their home, or a similar object. The basic premise is to provide an environment that elicits information about a person’s feelings about the targeted stimuli (e.g., self, family member). The examinee is thought to project his or her own perceptions of these targeted stimuli onto the drawings. Assessment relies on an accurate interpretation of the elements of the drawings as they relate to the client’s thoughts and feelings. Artistic talent is irrelevant. Rather, it is the configuration and style of the elements that is evaluated. For example, poor drawing symmetry may be reflective of insecurity or inadequacy, low levels of detail may be suggestive of withdrawal or depression, and large head size may be suggestive of expansiveness and aggression.
Projective Test Summary.
Projective tests have had a long history of use in the assessment of psychopathology. However, the reliability and validity of projective tests has been a long-standing controversy. At a minimum, the use of these tests calls for significant training and experience, and even the most skilled clinician must take great care to avoid potential judgment biases.
Objective Self-Report Inventories
Objective self-report inventories have been widely used for close to 70 years and continue to enjoy great popularity. Two of the most commonly used measures are the Minnesota Multiphasic Personality Inventory (MMPI) and the Millon Clinical Multiaxial Inventory (MCMI).
The Minnesota Multiphasic Inventory.
The MMPI-2 was originally designed as a diagnostic tool to identify specific DSM disorders. However, the findings from more than six decades of research on the instrument have expanded its use to include multiple behavioral and symptom correlates based on patterns of responding across its many subscales. In brief, the MMPI-2 consists of 557 true/false items that are scored to yield scores on 10 primary clinical scales. These primary scales retain their original labels (e.g., Hypochondriasis, Depression, Hysteria, Psychopathic Deviate), however, they are no longer interpreted as stand-alone scales but as reflective of a pattern of symptoms and behaviors shared by common groups.
The MMPI-2 also contains several “validity” indexes, including the K (Correction) scale and the L (Lie) scale, and a host of content-based and supplementary scales. Content-based scales are those that have been composed of items that, at face value, appear to represent domains of similar content. Examples include scales of Anxiety, Obsessiveness, Social Discomfort, and Family Problems. Supplementary scales are those that have been created by combining items, usually based on statistical rationales, to represent an area of clinical interest. Examples of supplemental scales include Repression, Ego Strength, Marital Distress, and Gender Role Identification.
Current interpretation strategies usually revolve around pattern analysis of scale elevations. Specific sets of scale score patterns are then associated with likely behavioral response patterns that have been seen in others with similar patterns. These symptom sets are then used to determine the fit of the examinee to specific diagnostic criteria. For example, people who obtain high scores on both Clinical Scale 2 (Depression) and Clinical Scale 9 (Introversion) have been shown to often be ruminative, worried about achievement, and self-centered. They often report feeling tense and anxious, and may engage in episodes alternating between excessive activity and apathy. They are sometimes diagnosed with depression or bipolar disorder.
The MMPI-2 has been criticized along several grounds. Given that it was originally established to identify severe psychopathology, it is viewed as limited in its ability to describe less severe pathology or normal personality characteristics. Additionally, despite its “objective” standing, the practice of interpreting patterns of scale scores leaves it open to clinical biases similar to those of the projective techniques. Nevertheless, the MMPI-2 has been shown to be extremely helpful in the diagnosis of a number of mental disorders, and it remains an efficient method of gathering diagnostic information.
Millon Clinical Multiaxial Inventory.
The newest iteration of the MCMI, the MCMI-III, is a 175-item, true/false self-report questionnaire designed to assess psychopathology, personality characteristics, and emotional adjustment. It is used for both diagnosis and character descriptions. Originally developed in 1977, the instrument has gone through several revisions, the most recent being in 1994. It currently includes 24 scales that are closely associated with the DSM-IV-TR diagnostic categories. As with the DSM-IV-TR, these scales are grouped in two broad categories. Axis I scales are those that are thought to reflect primary disorders of thought such as depression, anxiety, and schizophrenia. Axis II scales are those that are thought to reflect more enduring trait characteristics and are represented by the personality disorders such as borderline personality disorder or avoidant personality disorder. The MCMI-III includes four Modifying Indexes—Validity, Disclosure, Desirability, and Debasement. These scales are used to either invalidate the test due to inappropriate responding (Validity Index) or to modify the existing clinical scales by taking into account additional variables including the examinee’s response openness (Disclosure Index), response defensiveness (Desirability Index), and symptom exaggeration (Debasement Index).
The MCMI is based on Theodore Millon’s personality theory, which describes personality traits in terms of relatively enduring patterns of interpersonal coping styles. Personality styles evolve from the interaction between a person’s perceived sources of reinforcement and his or her avoidance of pain. These factors are moderated by the person’s tendency to actively or passively manipulate his or her environment to obtain favorable outcomes. For example, the categories of Pleasure versus Pain and Self versus Other are activated by either an Active or Passive way of obtaining satisfaction. According to Millon, all personality disorders are derivations of these combinations. Millon would thus identify an avoidant personality as influenced by sensitivity to pain as a negative reinforcer, an emphasis on the self as the source of reinforcement more than others, and using an active strategy to expose oneself to these factors.
Millon described the more severe clinical syndromes (e.g., DSM Axis I disorders such as schizophrenia or bipolar disorder) as acute reactions. Pathology is associated with ingrained personality styles that have become extremely rigid and inflexible, leading to greater impairment. Thus, when interpreting MCMI-III profiles, the psychologist will first pay attention to the Axis II (enduring trait) scales, followed by the Axis I scales.
The MCMI-III is also unique in its reliance on “base rates” of known diagnostic disorders to establish fit. In other words, the MCMI-III takes into account the prevalence of any given diagnostic category (e.g., antisocial) within the general population. Relatively rare disorders need a greater number of scale items to indicate their presence compared to more “common” disorders.
Because of the overlap of the MCMI-III with the DSM, its diagnostic interpretation is relatively straightforward. Overall, the MCMI-III has been shown to be predictive of DSM diagnostic categories.
Additional Self-Report Inventories.
Other self-report inventories used by psychologists include the California Psychological Inventory (CPI), the Sixteen Personality Factors test (16PF), and the Psychological Assessment Inventory (PAI). Developed by Harrison Gough, the CPI 434 is a 434-item true/false test similar in construction to the MMPI but developed to identify a more “normative” range of personality characteristics. It currently has 20 scales that fall into 4 broad categories: self-related, social-related, achievement-related, and interest-related. True to its intent, the CPI 434 provides data on personality style rather than personality disorder. Thus, it is used most often in industrial-organizational settings and employment settings and is popular in executive and leadership identification. There is also the CPI 260, which is a shorter version of the CPI 434.
The 16 PF was developed to measure the 16 primary factors that personality psychologist Raymond Cattell used to describe the personality characteristics of individuals. The 16 PF, now in its fifth edition, consists of 185 multiple-choice items that form 16 bipolar clinical scales. Bipolar scales yield scores that range from one extreme to the other on the dimension being measured. For example, the Reasoning scale is anchored from concrete to abstract; the Emotional scale is anchored from reactive to emotionally stable. In addition, global scores on Extraversion, Anxiety, Tough-Mindedness, Independence, and Self-Control are derived from the clinical scales. The test has been widely used to measure both normal and deviant personality styles. It is used in traditional clinical settings for diagnostic and treatment decisions, as well as in vocational settings.
The PAI is a 344-item inventory that consists of items having four response options (false—not at all true, slightly true, mainly true, very true). The PAI consists of 4 validity scales (Inconsistency, Infrequency, Negative Impression, Positive Impression), 11 scales directly assessing criteria associated with major mental disorders (e.g., depression, mania, and anxiety), 2 scales evaluating interpersonal relations (Dominance and Warmth), and 5 scales that yield treatment-based predictions (e.g., Suicidal Ideation and Treatment Rejection). It has been validated on both clinical and nonclinical populations and can be used with either population. The instrument yields separate standard scores (in this case, T scores) for comparison to both populations. The PAI has gained solid use over the approximate 15 years of its existence and is relatively easy and straightforward to interpret.
Behavioral Assessment Tools
A basic tenet of behaviorism and learning theory is that all behavior is learned. That includes pathological behavior. Some of this learning occurs as a result of stimulus-response relationships that are learned over time within a particular environmental context. Other behaviors are learned vicariously (i.e., by observing others and copying their behavior). The behavioral assessment of psychopathology relies on this basic tenet and focuses on a quantitative approach to describing problem behaviors that make up psychopathology. Thus, the major methods of behavioral assessment focus on the size, the strength, and the number of the problem variables assessed. As in other assessment methods, the behavioral assessment of psychopathology focuses on acquiring reliable and valid data. However, the data are typically restricted to directly observable or at least verbally describable phenomena that can be quantified. Behavioral assessment tools are quite varied and they are often quite specific and tailored to the circumstances of the individual.
Behavioral interviewing is a primary tool of behavioral assessment. Behavioral interviews focus on operationally defining problem behaviors and on elucidating the relationships between those behaviors and precipitating events (antecedents) and resultant consequences. Since the ultimate goal of behavioral assessment is to change problem behaviors, the focus tends to be on the more immediate antecedents and consequences of problem behaviors. Less attention is given to obtaining detailed historical information about life events such as childhood experiences.
Behavioral assessment also emphasizes the direct observation of problems and the use of behavioral assessment checklists. Behavioral checklists are tools that assist in quantifying specific behaviors. They are typically short, specific to particular disorders, and easy to complete. Behavioral checklists are most often completed by clients, but can be used in a question-and-answer format by an examiner. They can be extremely helpful for gathering self-reported symptom information that can be compared to a normative distribution.
Examples of widely used behavioral checklists include the Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI), and the State-Trait Anxiety Inventory (STAI). The second edition of the BDI (BDI-II) is a 21-item self-rating scale consisting of items that cover a broad range of depression-related symptoms. Like most behavioral checklists, it takes only a few minutes to complete and because the responses represent examinees’ ratings of specific behaviors, it provides a description of the kinds of symptoms a client reports. The BDI and other checklists can be summed up for comparison to different populations, and thus it gives an indication of the severity of depressive symptoms. The BAI is a similar tool that assesses the presence and severity of specific symptoms of anxiety.
The STAI is a well-established behavioral checklist developed by Charles Spielberger that focuses on behaviors related to both stable, relatively enduring trait-based features of anxiety, and situational, state-based features of anxiety. The State Anxiety and Trait Anxiety scales each consist of 20 items that offer four response alternatives (not at all, somewhat, moderately so, very much so) for describing the extent to which features of anxiety are personally descriptive. The State scale asks respondents to answer in terms of how they feel at the moment, while the Trait scale directs them to answer in terms of how they generally feel. The STAI is easy to complete and has been shown to be a good indicator of self-perceived anxiety.
The Symptom Checklist-90-R (SCL-90-R) is a broader-based tool that uses relatively few items to form behavior-based scales that have been associated with specific diagnostic categories. Developed by Leonard Derogatis, the SCL-90-R scales assess nine primary symptoms (e.g., depression, hostility, obsessive-compulsive, psychoticism) and three global indexes of overall distress. Its relative comprehensiveness, brevity, and easy-to-use checklist format make it a useful tool for psychologists.
Clinical Judgment in Assessing Psychopathology
It is critical that psychologists be sure that the information they are obtaining provides an accurate reflection of the client’s circumstances when gathering assessment information. Most psychologists make their own decisions regarding the accuracy, impact, relative weight, and usefulness of the information they gather, but the ability of clinicians to do this has been a point of controversy. In 1954 Paul Meehl questioned the ability of psychologists to make accurate inferences (i.e., predictions) from the assessment information they obtain. Since that time numerous studies have shown that the use of statistical algorithms to make predictions yields greater accuracy than clinical judgment.
Danny Wedding and David Faust have described a number of clinical biases that lessen the accuracy of an assessment of psychopathology. These include hindsight bias, or the tendency once something is known to believe that the outcome could have been more easily predicted than is the actual case. Confirmatory bias is the tendency to look for evidence supporting one’s early hypotheses while tending to overlook evidence that would be contrary to those hypotheses. Over-reliance on salient data is another bias often attributable to the assessment process. This occurs when one pays greater attention to information that appears more “impressive” and ignoring less dramatic information. The underutilization of base rates is another limitation to which psychologists are prone. Base rates (i.e., the prevalence or frequency with which an event occurs in the population) provide important information about the likelihood of observing a given disorder, but psychologists often ignore base rate data. Another judgment shortcoming Wedding and Faust point out in assessment is the common failure to analyze covariation. By this they mean that the likelihood that an observed relationship (e.g., an increase in depressive features and a new marriage) could be influenced by an additional factor (e.g., a job change). Finally, the cognitive limitations inherent in all persons, (e.g., limited working memory capacity, limits in complex processing, and inaccuracies of information manipulation) also limit the ability of psychologists to make accurate predictions from assessment data.
Skilled psychologists are aware of these biases and take steps to minimize them. Specifically, they use comprehensive structured or semistructured interview techniques and assessment tools that have been empirically proven to be both reliable and valid. This reduces the likelihood that relevant information will be overlooked, resulting in an overreliance on narrow description. To minimize hindsight and confirmatory biases, they give careful attention to data that both support and do not support tentative conclusions. They base diagnoses on specific criteria to reduce the influence of cognitive biases and stereotyping due to factors such as gender, age, and ethnicity. In addition, they recognize that memory is a reconstructive process that provides numerous opportunities for biases to influence psychologists’ conclusions and minimize this problem by attempting to minimize their reliance on their own memory. Attending to base rates and understanding the population with which psychologists work can effectively guide expectations regarding the amount of evidence necessary for a diagnosis and insuring data collection specific to that population. Finally, skilled psychologists seek feedback regarding the accuracy and usefulness of their judgments to help shape and refine their diagnostic process.
Research has shown that actuarial-based assessment tools have almost uniformly proved to be more accurate than clinical judgment alone. Nevertheless, the clinical assessment of psychopathology has remained a judgment call. Thus, it is vitally important that psychologists base their judgments on the most reliable and valid tools available, and that they understand the limitations of their judgments.
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