How can one accurately determine whether a person has a mental illness?

Methods for accurately diagnosing whether someone has a mental illness generally include professional medical evaluation through interviews, mental status examination, psychological scale assessments, physical disease screening, and observation of illness course and social functioning. A detailed analysis is as follows:

1. Professional Medical Interview Assessment: A psychiatrist conducts a detailed interview to understand the individual's medical history, family history of mental disorders, and recent emotional and behavioral changes. Information from family members or informed individuals may also be collected to provide foundational evidence for initial assessment.

2. Mental Status Examination: The doctor evaluates the individual through face-to-face communication, observing aspects such as perception, thought processes, mood, and volitional behavior. The presence of abnormalities such as hallucinations, delusions, disorganized speech, or extreme mood fluctuations is assessed to determine whether mental activity follows normal logical patterns.

3. Psychological Scale Assessment: Standardized psychological assessment tools—such as the Symptom Checklist (SCL-90) and the Minnesota Multiphasic Personality Inventory (MMPI)—are used to quantitatively evaluate an individual’s psychological state. These scores help clinicians identify the presence and severity of psychiatric symptoms.

4. Physical Disease Screening: Tests including complete blood count, biochemical panels, and brain imaging are performed to rule out physical conditions—such as thyroid dysfunction, brain lesions, or infections—that may cause psychiatric symptoms. This helps prevent misdiagnosing secondary psychiatric manifestations due to physical illnesses as primary mental disorders.

5. Observation of Illness Course and Social Functioning: The duration of abnormal behaviors is monitored. If symptoms persist beyond a certain period (e.g., more than two weeks) and significantly impair work, study, or interpersonal relationships, this, combined with other diagnostic findings, increases diagnostic accuracy.

When mental abnormalities are suspected, individuals should seek professional care at a licensed hospital’s psychiatry or psychology department, avoiding self-diagnosis or reliance on non-professional opinions. Once diagnosed, patients should follow medical treatment plans and receive support from family and society to aid in the recovery of social functioning.