Psychiatric assessment, descriptive psychopathology and formulation
A psychiatric assessment begins with a person’s concerns, priorities and account of what has changed. Establish chronology, baseline functioning, sleep, physical symptoms, medicines, substance exposure, relationships and relevant developmental history. Information from another person can be valuable, but its reliability, consent and confidentiality context must be considered. Separate what was observed, what was reported and what the clinician inferred. A diagnostic label without that evidence does not communicate the reasoning.
The mental-state examination describes the present encounter. Appearance and behavior, speech, mood and affect, thought form and content, perception, cognition, insight and judgment are related but distinct observations. Mood is not the same as the emotion the observer perceives in the interview. Derailment describes disrupted associations in speech rather than simply an unusual opinion. An illusion involves a real stimulus that is misperceived; a hallucination is a perception-like experience without a corresponding external stimulus. Internal versus external location alone is not a reliable boundary between genuine and unreal illness.
Assess symptoms within their cultural and interpersonal context. A belief cannot be called delusional merely because it differs from the clinician’s worldview. Ask about the person’s meaning, degree of conviction, alternatives, associated experiences and effects on life. Thought insertion, broadcasting or passivity experiences are useful descriptions, but none alone establishes one specific disorder. Mood episodes, substances, neurological conditions and other medical causes can produce overlapping presentations.
Formulation integrates predisposing, precipitating, maintaining and protective factors into an account that can guide care. It should explain uncertainty and alternative possibilities, rather than turn a list of risk factors into a claim of causation. Screening and severity scales can structure observations or monitor change; they do not replace a clinical assessment or independently decide admission, discharge, capacity or diagnosis. Test interpretation requires the correct instrument, version, language, norms and purpose.
Acute changes in attention, consciousness, orientation or neurological function require particular attention to physical illness, intoxication, withdrawal or medication effects. Safety assessment includes the person’s current situation, intent, access to means, supports and foreseeable changes, not a score alone. Record a collaborative plan and the reasoning for urgent escalation where indicated. This chapter concerns professional assessment principles, without claiming one country’s statutory authority or a universal diagnostic timetable.
Measurement interpretation also requires a clearly stated comparison. Reliability concerns consistency or precision under specified conditions; validity concerns evidence supporting a proposed interpretation and use. A reliable instrument is not automatically valid for a different population or decision. Empirically estimated correlations can be negative, so a surprising test-retest result calls for investigation of scoring, sampling and procedures rather than a claim that a negative coefficient is mathematically impossible.
A percentile describes relative position in a named comparison group, not percentage correct or the proportion of the curriculum mastered. A z score expresses distance from the mean in standard-deviation units. Under the stated conventional transformation, a T score equals 50 plus ten times z, so z equal to one corresponds to T equal to 60. A normal-distribution percentile approximation requires that assumption; it is not guaranteed by having a standard score. A grade-equivalent score does not establish an appropriate grade placement across subjects.
Choose a test with relevant evidence, accessible administration and an appropriate norm group, then interpret it alongside history and other observations. Accommodations and changes to administration may affect interpretation and should be documented. A high-stakes decision should not be inferred from a small score difference without considering measurement error, fairness and actual functional or educational evidence. These principles apply to counseling and vocational assessment without authorizing every practitioner to administer specialist clinical instruments.