Medical Assessment of the Patient With Psychiatric Symptoms

ByMichael B. First, MD, Columbia University
Reviewed/Revised Oct 2024
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Medical assessment of patients with psychiatric symptoms seeks to identify 3 things:

  • General medical disorders mimicking psychiatric disorders

  • General medical disorders caused or exacerbated by psychiatric disorders or their treatment

  • General medical disorders accompanying psychiatric disorders

Numerous general medical disorders cause symptoms that mimic specific psychiatric disorders (see table Selected Psychiatric Symptoms Due to General Medical Disorders). Other general medical disorders may not mimic specific psychiatric syndromes but instead have an impact on mood or alertness.

Many medications can cause psychiatric symptoms; the most common classes of medication-related causes are

Numerous other medications and medication classes have also been implicated; they include some classes that may not ordinarily be considered (eg, antibiotics, antihypertensives). Substances such as alcohol, amphetamines, marijuana (cannabis), , hallucinogens, and phencyclidine (PCP), particularly with frequent use or higher doses, are also frequent causes of psychiatric symptoms. Withdrawal from alcohol, barbiturates, or benzodiazepines may cause psychiatric symptoms (eg, anxiety) in addition to symptoms of physical withdrawal.

Patients with a mental disorder may develop an unrelated physical disorder (eg, meningitis, diabetic ketoacidosis) that causes new or worsened mental symptoms. Thus, a clinician should not assume that all mental symptoms in patients with a known mental disorder are due to that disorder. The clinician may need to be proactive in addressing possible physical causes for mental symptoms, especially in patients unable to describe their physical health because they have psychosis or dementia.

Pearls & Pitfalls

  • Do not assume that all psychiatric symptoms in patients with a known psychiatric disorder are due to that disorder.

Patients presenting for psychiatric care occasionally have undiagnosed general medical disorders that are not the cause of their psychiatric symptoms but nonetheless require evaluation and treatment. Such disorders may be unrelated (eg, hypertension, angina) or caused by the psychiatric disorder (eg, undernutrition due to lack of motivation to eat resulting from chronic schizophrenia) or its treatment (eg, hypothyroidismhyperlipidemia secondary to use of atypical antipsychotics).

Table
Table

Evaluation

Assessment by history, physical examination, and sometimes laboratory testing or brain imaging (1) is required for patients with

  • New-onset psychiatric symptoms (ie, no prior history of similar symptoms)

  • Qualitatively different or unexpected symptoms in a patient with a known or stable psychiatric disorder

  • Psychiatric symptoms that are unusual based on patient characteristics (eg, begin at an unexpected age—new-onset psychosis in an older adult)

The goal of medical assessment is to diagnose underlying and concomitant general medical disorders rather than to make a specific psychiatric diagnosis.

History

History of present illness should note the nature of symptoms and their onset, particularly whether onset was sudden or gradual and whether symptoms followed any possible precipitants (eg, trauma, illness, starting or stopping of a recreational drug or substance). The clinician should ask whether patients have had previous episodes of similar symptoms, whether a mental disorder has been diagnosed and treated, and, if so, whether patients have stopped taking their drugs.

Review of systems seeks symptoms that suggest possible causes:

Past medical history should identify general medical disorders that can cause psychiatric symptoms (eg, thyroid, liver, or kidney disease; diabetes; HIV infection). All prescription and over-the-counter medications should be reviewed, and patients should be queried about alcohol and illicit substance use. Family history of disorders, particularly of thyroid disease and multiple sclerosis, is assessed. Risk factors for infection (eg, unprotected sex, needle sharing, recent hospitalization, residence in a group facility) are noted.

Physical examination

Vital signs are reviewed, particularly for fever, tachypnea, hypertension, and tachycardia. Mental status is assessed if there is a suspicion of altered level of consciousness.

A physical examination is done, targeted based on the type and severity of symptoms:

  • Signs of infection (eg, meningismus, lung congestion, flank tenderness)

  • The neurologic examination (including gait testing and weakness)

  • Funduscopy to detect signs of increased intracranial pressure (eg, papilledema, loss of venous pulsations)

Signs of liver disease (eg, jaundice, ascites, spider angiomas) should be noted. The skin is carefully inspected for self-inflicted wounds or other evidence of external trauma (eg, bruising).

Interpretation of findings

The findings from the history and physical examination help interpret possible causes and guide testing and treatment.

Confusion and inattention (reduced clarity of awareness of the environment, suggesting delirium), especially if of sudden onset, fluctuating, or both, indicate the presence of a general medical disorder. However, the converse is not true (ie, a clear sensorium does not confirm that the cause is a psychiatric disorder). Other findings that suggest a general medical condition include

  • Abnormal vital signs (eg, fever, tachycardia, tachypnea)

  • Meningeal signs and symptoms (eg, headache, photophobia, neck rigidity)

  • Abnormalities noted during the neurologic examination, including aphasia

  • Disturbance of gait, balance, or both

  • Urinary or fecal incontinence

Some findings help suggest a specific cause, especially when symptoms and signs are new or have changed from a long-standing baseline:

  • Dilated pupils (particularly if accompanied by flushed, hot, dry skin): Anticholinergic drug effects

  • Constricted pupils: Opioid effects or pontine hemorrhage

  • Rotary or vertical nystagmus: Phencyclidine intoxication

  • Horizontal nystagmus: Often accompanies diphenylhydantoin toxicity

  • Garbled speech or inability to produce speech: A brain lesion (eg, stroke)

  • A preceding history of relapsing-remitting neurologic symptoms, particularly when a variety of nerves appear to be involved: Multiple sclerosis or vasculitis

  • Stocking-glove paresthesias: Possibly thiamin or vitamin B12 deficiency

In patients with hallucinations, the type of hallucination is not particularly diagnostic, except that command hallucinations or voices commenting on the patient’s behavior probably represent a psychiatric disorder.

Symptoms that began shortly after significant physical trauma or after beginning a new medication may be due to those events. Alcohol or illicit drug use may or may not be the cause of psychiatric symptoms; about 10 to 45% of patients with a psychiatric disorder (varies by diagnosis) also have a substance use disorder (dual diagnosis) (2).

Pearls & Pitfalls

  • A substance use disorder may or may not be the cause of new psychiatric symptoms; about 10 to 45% of patients with a psychiatric disorder also have a substance use disorder.

Testing

Testing varies depending on signs and symptoms.

Patients with a known psychiatric disorder who have an exacerbation of their typical symptoms and no new physical symptoms, a normal mental status, normal physical examination (including vital signs and pulse oximetry), and normal fingerstick glucose testing, do not typically require further laboratory testing.

Although new-onset psychiatric symptoms or marked change in the nature of symptoms in patients with a known psychiatric disorder may be due to a medical rather than a psychiatric disorder, it is unclear how commonly such a medical disorder is asymptomatic, and there is no consensus on routine laboratory testing of medically asymptomatic patients. For patients with a known psychiatric disorder and new-onset psychiatric symptoms or marked change in the nature of symptoms, clinicians may do one or more of the following to screen for potential medical disorders:

  • Complete blood count

  • Electrolyte levels (including calcium and magnesium), blood urea nitrogen, and creatinine

  • Erythrocyte sedimentation rate or C-reactive protein

  • HIV testing

  • Urinalysis

Electrolyte and renal function tests may help inform subsequent medication management (eg, for medications that require adjustment in patients with renal insufficiency). Also, for some psychotropic medications, testing should be done to confirm a therapeutic level.

Patients with signs or symptoms of a general medical disorder should have testing appropriate to diagnose that disorder:

  • Head CT: Patients with new-onset psychiatric symptoms or with delirium, headache, history of recent physical trauma, or focal neurologic findings (eg, weakness of an extremity)

  • Lumbar puncture: Patients with meningeal signs or with normal head CT findings plus fever, headache, or delirium

  • > 40 years with new-onset psychiatric symptoms (particularly females or patients with a family history of thyroid disease)

  • Liver tests: Patients with symptoms or signs of liver disease, with a history of alcohol or substance use disorder, or with no obtainable history

Less often, findings may suggest testing for systemic lupus erythematosus, syphilis, demyelinating disorders, Lyme disease, or vitamin B12 or thiamin deficiency, especially in patients presenting with signs of dementia.

Toxicology screening (eg, urine drug screen, blood alcohol level) is done if the patient has a recent history of substance use disorder or physical signs suggesting intoxication or recent substance use (eg, needle marks).

Evaluation references

  1. 1. Anderson EL, Nordstrom K, Wilson MP, et al: American Association for Emergency Psychiatry Task Force on Medical Clearance of Adults: Part I: Introduction, review and evidence-based guidelines. West J Emerg Med 18(2):235–242, 2017. doi: 10.5811/westjem.2016.10.32258

  2. 2. Toftdahl NG, Nordentoft M, Hjorthøj C: Prevalence of substance use disorders in psychiatric patients: A nationwide Danish population-based study. Social psychiatry and psychiatric epidemiology. Soc Psychiatry Psychiatr Epidemiol 51(1):129-140, 2016. doi: 10.1007/s00127-015-1104-4

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