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Abnormal Psychology Unit 3: Assessment, Diagnosis and the DSM-5-TR

Before treating anyone, clinicians gather information with interviews, tests and observation, then decide whether the person's pattern fits a diagnosis. This unit covers the tools, how to judge their quality, and the strengths and risks of the DSM-5-TR system.

Covers: Reliability and validity of assessment tools, Clinical interviews and the mental status exam, Personality tests: MMPI and projective techniques, Intelligence, neuropsychological and neuroimaging assessment, Behavioral assessment and self-monitoring, The DSM-5-TR and ICD-11 classification systems, Sensitivity, specificity and base rates, Dangers of labeling and diagnostic bias

Study guide

Clinical assessment is the process of collecting information about a person's problems, history and functioning. Every tool is judged by reliability and validity. Reliability means consistency: test-retest reliability asks whether scores stay similar over time, and interrater reliability asks whether different clinicians reach the same conclusion. Validity means the tool measures what it claims to measure. Content validity asks whether items cover the full domain, predictive validity asks whether scores forecast future behavior, concurrent validity asks whether scores agree with other measures given at the same time, and construct validity asks whether the tool fits the theory behind the concept. A test can be reliable without being valid, like a scale that is always five pounds off, but it cannot be valid without being reliable. Standardization means giving and scoring a test the same way and comparing results with norms.

The clinical interview is the most common assessment tool. Unstructured interviews are flexible, while structured interviews, such as the Structured Clinical Interview for DSM-5 (SCID-5), ask set questions in a set order and have higher reliability. The mental status exam records appearance, behavior, mood and affect, speech, thought process and content, perception, cognition and insight. Personality tests come in two types. The Minnesota Multiphasic Personality Inventory (MMPI-2 and MMPI-3) is an objective self-report test of true-false items with clinical scales and validity scales that detect careless, defensive or exaggerated responding. Projective tests, such as the Rorschach inkblot test and the Thematic Apperception Test (TAT), present ambiguous stimuli on the theory that people project their concerns onto them; their reliability and validity are weaker and more debated.

Other tools measure cognition and the brain. Intelligence tests such as the Wechsler Adult Intelligence Scale (WAIS) produce scores with a mean of 100 and a standard deviation of 15, so about 68% of people score between 85 and 115 and about 95% between 70 and 130. Neuropsychological tests, such as the Bender Visual-Motor Gestalt Test, detect brain impairment through performance on memory, perception and motor tasks. Neuroimaging includes structural methods (CT and MRI) that show anatomy and functional methods (PET and fMRI) that show activity. Behavioral assessment records specific behaviors, their antecedents and their consequences, often through direct observation or self-monitoring, where clients log their own behavior. Psychophysiological measures, such as heart rate or skin conductance, track bodily responses to emotion. Clinicians combine several sources, since no single tool is enough.

Diagnosis matches a person's pattern of symptoms to a category. In the United States the main system is the American Psychiatric Association's DSM-5-TR (2022), a text revision of the DSM-5 (2013). The DSM-5-TR lists criteria for each disorder, including the number of symptoms, required duration and the requirement of clinically significant distress or impairment. It uses specifiers (for example, with anxious distress) and severity ratings to add detail, includes some dimensional measures, and lists codes for other conditions such as relationship problems. The DSM-5-TR added prolonged grief disorder. Worldwide, the World Health Organization's ICD-11 is used, and DSM codes are linked to ICD codes. Comorbidity, the presence of two or more disorders in one person, is common and complicates both diagnosis and treatment.

Diagnoses have real benefits: they allow communication, guide treatment and research, and support insurance claims. But they also carry risks. In David Rosenhan's 1973 study, healthy pseudopatients who claimed to hear voices were admitted to hospitals and kept for days or weeks, which Rosenhan argued showed that labels color how all later behavior is seen; later writers have questioned some of his data. Labels can lead to stigma, self-fulfilling prophecies and clinician bias based on race, gender or culture. Diagnostic accuracy also depends on base rates. Sensitivity is the proportion of true cases a test detects, and specificity is the proportion of non-cases it correctly clears. When a disorder is rare, even a good screening test produces many false positives, so the positive predictive value (the chance that a positive result is a true case) can be surprisingly low.

Key ideas

• Reliability is consistency and validity is accuracy; a valid tool must be reliable, but a reliable tool is not always valid.
• Structured interviews are more reliable than unstructured ones because every clinician asks the same questions.
• Objective tests like the MMPI have stronger psychometric support than projective tests like the Rorschach and TAT.
• The DSM-5-TR is a categorical system with criteria, duration rules, specifiers and severity ratings, plus some dimensional elements.
• Most diagnoses require clinically significant distress or impairment, not just the presence of symptoms.
• When base rates are low, positive screening results are often false positives.
• Labels can help communication and treatment but can also produce stigma and biased judgments.

Formulas and rules

Common mistakes

• Saying a reliable test must be valid.
• Confusing sensitivity (catching true cases) with specificity (clearing non-cases).
• Ignoring base rates and assuming a positive screen almost certainly means the disorder is present.
• Thinking the DSM-5-TR explains the causes of disorders; it mostly describes them.
• Calling the MMPI a projective test; it is an objective self-report inventory.

Before the test, make sure you can

• Define and distinguish test-retest reliability, interrater reliability and the main types of validity.
• Compare structured and unstructured interviews and list the parts of a mental status exam.
• Contrast objective tests like the MMPI with projective tests like the Rorschach and TAT.
• Interpret IQ scores using the mean of 100 and standard deviation of 15.
• Describe how the DSM-5-TR is organized, including criteria, specifiers, severity and its link to ICD-11.
• Calculate sensitivity, specificity and positive predictive value from described data.
• Explain the benefits and risks of diagnostic labels, including the Rosenhan study.

Words to know

Clinical assessment

Collecting and interpreting information about a person's symptoms, history and functioning.

Reliability

The consistency of an assessment tool across time, raters or items.

Validity

The extent to which a tool measures what it is intended to measure.

Predictive validity

How well a measure's scores forecast future behavior or outcomes.

Standardization

Using the same procedures for giving and scoring a test and comparing scores to norms.

Structured interview

An interview with a fixed set of questions in a set order, such as the SCID-5.

Mental status exam

A structured summary of a person's appearance, behavior, mood, thought, perception, cognition and insight.

MMPI

The Minnesota Multiphasic Personality Inventory, an objective true-false personality test with clinical and validity scales.

Projective test

A test using ambiguous stimuli, such as inkblots, on the theory that people project inner concerns onto them.

Thematic Apperception Test

A projective test in which people tell stories about ambiguous pictures of people.

Self-monitoring

A behavioral assessment method in which clients record their own behaviors, thoughts or feelings as they occur.

fMRI

Functional magnetic resonance imaging, which shows brain activity by tracking changes in blood oxygen.

DSM-5-TR

The 2022 text revision of the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders.

ICD-11

The World Health Organization's International Classification of Diseases, used for diagnosis worldwide.

Specifier

A DSM label added to a diagnosis to describe a subtype or feature, such as 'with panic attacks'.

Comorbidity

The presence of two or more disorders in the same person.

Sensitivity

The proportion of people with a disorder whom a test correctly identifies as positive.

Specificity

The proportion of people without a disorder whom a test correctly identifies as negative.

Positive predictive value

The probability that a person who tests positive actually has the disorder.

Sample practice questions

30 more questions like these, from level 1 to 5, are in the practice set.