What is the role of history, physical examination, and mental status examination in psychiatric evaluations?

Role of History, Physical Examination, and Mental Status Examination in Psychiatric Evaluations

History, physical examination, and vital signs are the cornerstone of psychiatric evaluation, with a pooled yield of 15.6% and 14.9% respectively for detecting clinically significant medical conditions—far superior to routine laboratory or radiographic testing (1.1% yield)—and should guide all subsequent diagnostic decisions. 1, 2

Primary Goals of the Psychiatric Evaluation

The psychiatric evaluation serves two critical functions that directly impact patient morbidity and mortality 1:

• Determine if psychiatric symptoms are caused or exacerbated by underlying medical conditions requiring acute treatment 1
• Identify comorbid medical conditions that could benefit from immediate intervention, even if unrelated to the psychiatric presentation 1, 2

The evaluation should establish "medical stability" (absence of medical conditions requiring acute evaluation/treatment) rather than attempting to "rule out all potential medical etiologies," which is clinically impossible 1

The History: Highest Yield Component

History has a pooled yield of 15.6% for detecting clinically significant conditions that change diagnosis or management—making it the single most valuable component of psychiatric evaluation 2

Key Historical Elements to Obtain

• Vital signs assessment: Abnormal vital signs are among the most important predictors of underlying medical pathology 1
• Onset and temporal pattern: New-onset or acute changes in psychiatric symptoms warrant more extensive medical evaluation 1
• Medication history: Including psychiatric medications, recent changes, and potential for withdrawal syndromes 1
• Substance use: Alcohol, amphetamines, barbiturates, benzodiazepines, cocaine, and other drugs of abuse 1
• Recent medical illnesses or treatments: Infections, metabolic disturbances, endocrine disorders 1
• Collateral information: From caregivers or others who know the patient's baseline, as patients frequently minimize symptoms 1

Interview Technique Considerations

• Interview patients and caregivers separately and together to obtain complete information 1
• Discuss confidentiality limits with adolescents to facilitate honest conversation 1
• Obtain information about psychosocial stressors: Family conflict, relationship problems, bullying, academic difficulties, legal troubles 1

Physical Examination: Second Highest Yield

Physical examination has a pooled yield of 14.9% for detecting conditions requiring management changes, with no significant difference whether performed by psychiatrists or non-psychiatrists 2

Critical Systems to Examine

The physical examination must prioritize three systems where life-threatening conditions commonly present as psychiatric symptoms 1:

• Neurologic system: Focal deficits, altered mental status, signs of increased intracranial pressure, meningismus 1
• Cardiac system: Arrhythmias, murmurs, signs of heart failure 1
• Respiratory system: Hypoxia, hypercarbia, respiratory distress 1

Additional Physical Examination Components

• Signs of self-injury or trauma: Particularly in suicidal patients 1
• Toxidromes: Pupil size, diaphoresis, tremor, vital sign abnormalities suggesting intoxication or withdrawal 1
• Signs of systemic illness: Jaundice, cyanosis, edema, skin lesions 1

Mental Status Examination: Essential Psychiatric Component

The mental status examination provides systematic assessment of psychiatric symptoms and cognitive function 1, 3

Core Components to Document

• Appearance and general behavior: Grooming, hygiene, eye contact, cooperation 1, 3
• Motor activity: Psychomotor agitation or retardation, abnormal movements 3, 4
• Speech: Rate, volume, fluency, coherence 3, 4
• Mood and affect: Patient's subjective emotional state and observed emotional expression 3, 4
• Thought process: Organization, flow, and logic of thinking 1, 3
• Thought content: Delusions, obsessions, suicidal or homicidal ideation 1, 3
• Perceptual disturbances: Hallucinations (auditory, visual, tactile) 1, 3
• Sensorium and cognition: Level of consciousness, orientation, attention, memory 3, 4
• Insight and judgment: Patient's understanding of their condition and decision-making capacity 3, 4

Tools like the Mini-Mental Status Examination can be useful adjuncts 1

Medical Conditions That Masquerade as Psychiatric Disorders

A vast array of medical conditions can present with primarily psychiatric symptoms, requiring vigilance 1:

Neurologic Causes

• Cerebrovascular: Stroke, TIA, intracerebral/subdural/subarachnoid/epidural hemorrhage, aneurysms, venous thrombosis 1
• Structural: CNS tumors, hydrocephalus, congenital malformations 1
• Infectious: Meningitis, encephalitis, brain abscess, HIV, syphilis 1
• Seizure disorders: Including post-ictal states 1
• Neurodegenerative: Multiple sclerosis, Huntington chorea 1
• Delirium: Including "ICU psychosis" 1

Metabolic and Endocrine Causes

• Electrolyte disturbances: Hyponatremia, hypocalcemia 1
• Glucose abnormalities: Hypoglycemia, hyperglycemia, ketoacidosis 1
• Renal/hepatic: Uremia, hyperammonemia, hepatic encephalopathy 1
• Thyroid: Hyperthyroidism, thyroid storm, hypothyroidism 1
• Adrenal: Addison disease, Cushing disease 1
• Pituitary/parathyroid disorders: Hypopituitarism, hypo/hyperparathyroidism 1
• Pheochromocytoma 1

Respiratory Causes

• Hypoxia and hypercarbia/hypercapnia 1
• Respiratory failure 1

Medication and Substance-Related Causes

• Drug withdrawal: Alcohol, amphetamines, barbiturates, benzodiazepines, cocaine, psychiatric medications 1
• Drug overdose or intoxication: Phencyclidine, heroin, cocaine, marijuana, MDMA 1

When to Obtain Laboratory and Radiographic Testing

Routine laboratory testing and brain imaging have extremely low yield (1.1%) and should NOT be performed routinely 1, 2

Indications for Targeted Testing

Laboratory and radiographic studies should be obtained ONLY when indicated by history and physical examination 1:

• Altered mental status not explained by primary psychiatric disorder 1
• Unexplained vital sign abnormalities 1
• New-onset or acute changes in psychiatric symptoms 1
• Abnormal neurologic findings on examination 1
• Specific historical or physical findings suggesting medical etiology 1

Evidence Against Routine Testing

• Routine urine toxicology screens: Only 5% positive in one study, with no changes in patient management 1
• Routine brain CT scans: In patients with new-onset psychosis and no focal neurologic findings, only 1.2% had clinically significant findings, with most abnormalities having no relevance to the patient's condition 1
• Routine laboratory panels: Less than 1 test in 50 results in clinically meaningful findings, with false-positives 8 times more common than true-positives 1

Higher-Risk Populations

Certain subgroups may benefit from more extensive evaluation 2:

• Disoriented or agitated patients 2
• Older patients (≥65 years) 1, 2
• Patients with drug/alcohol histories 1
• Lower socioeconomic status patients 1

Clinical Decision Algorithm

For clinically stable patients (alert, cooperative, normal vital signs, noncontributory history and physical examination): No routine laboratory or radiographic testing is needed 1

For patients with concerning findings: Obtain targeted testing based on specific abnormalities identified 1

When discrepancies arise between emergency and psychiatry clinicians: Direct communication between attending physicians is recommended 1

Common Pitfalls to Avoid

• Over-reliance on laboratory testing: History and physical examination are far superior for detecting clinically significant conditions 2
• Ordering "routine" test batteries: This approach is costly, low-yield, and increases false-positive results 1
• Failing to obtain collateral information: Patients frequently minimize symptoms or lack insight 1
• Inadequate attention to vital signs: Abnormal vital signs are critical predictors of medical pathology 1
• Neglecting the physical examination: Some clinicians inappropriately defer all medical assessment, but physical examination has 14.9% yield 2
• Unnecessary radiation exposure: Routine brain CT in pediatric patients is particularly concerning given long-term radiation risks 1