Mental Disorder: Definition & Diagnosis

Study Notes

The concept of "mental disorder" is based on philosophical assumptions about the relationship between mind and body.
Monism (the world consists of one substance) and dualism (the mind and body are separate) offer different perspectives on mental disorders.
Reductive materialism, a form of monism, views mental disorders as brain disorders, while dualism views them as disorders of mental processes.
The scope of mental disorders has broadened, encompassing a wide range of severity, from brain diseases to behavioral patterns to problematic conditions.
Defining mental disorders is challenging and there is no consistent, logical way to do so.
Mental disorder diagnoses can carry stigma, be used for political persecution, and be misused as excuses for behavior.

Attempts to define mental disorders grapple with dichotomies like normal vs. abnormal and illness vs. evil.
Different criteria for abnormality include deviance (statistical, moral, cultural), distress, dysfunction, and danger.

Most people hold prototype conceptions of mental disorders, often influenced by real-life experiences, media portrayals, or professional training.
These prototypes may or may not be accurate.

The Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, Text Revision (DSM-5-TR) is the current official diagnostic manual for mental disorders.
It defines a mental disorder as a clinically significant behavioral or psychological syndrome associated with distress, disability, or increased risk of negative outcomes.
The DSM-5-TR emphasizes phenotypic diagnosis based on observable signs and symptoms, abandoning intra-psychic conjectures.
It is field-tested for reliability and acknowledges psychosocial factors.
It employs a decision-tree approach with inclusion and exclusion criteria.

Diagnosis serves many purposes including prognosis, treatment implications, communication, legal reasons, financial considerations, and research.
The process of clinical assessment involves gathering information through the clinical interview, which is the most valuable diagnostic tool.

The clinical interview typically lasts around one hour and aims to assess current and past symptoms, observe signs, and obtain personal and family history.
It also gathers information about mental health history, treatments, and suitability for psychotherapy or referral to other professionals.

Information from family members, physicians, employers, medical charts, previous psychological testing, and case summaries is valuable in diagnosis.

Family history influences the risk of specific mental disorders such as anxiety disorders, bipolar disorder, schizophrenia, panic disorder, unipolar depression, and alcoholism.

Phenotypic diagnosis focuses on signs, symptoms, course, and outcome, while genotypic diagnosis focuses on causes, including genes, germs, and tissue abnormalities.
Endophenotypic diagnosis utilizes lab tests, biomarkers, and behavioral tests to identify subclinical signs.

The DSM-5-TR emphasizes phenotypic diagnosis, abandoning intra-psychic terms.
It features field-tested reliability, acknowledgement of medical and psychosocial factors, and a decision-tree approach.

Z-codes represent psychosocial situations that may affect treatment but are not mental disorders, including noncompliance with treatment, relational problems, abuse, neglect, occupational problems, and acculturation issues.

No single sign or symptom defines a mental disorder, meaning that diagnosis is based on a pattern of signs and symptoms.
The patterns of syndromes and courses of illness define the nosology of mental disorders.

Diagnoses are informed guesses based on the best fit between the patient's presentation and available information.
They are not set in stone and may change with new information or changes in the patient's presentation.
Mental disorders are frequently comorbid, meaning patients often require multiple diagnoses.