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Medical Assessment of the Patient With Mental Symptoms


Michael B. First

, MD, Columbia University

Last full review/revision Feb 2020| Content last modified Feb 2020
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Patients with mental complaints or concerns or disordered behavior present in a variety of clinical settings, including primary care and emergency treatment centers. Complaints or concerns may be new or a continuation of a history of mental problems. Complaints may be related to coping with a physical condition or be the direct effects of a physical condition on the brain. The method of assessment depends on whether the complaints constitute an emergency or are reported in a scheduled visit. In an emergency, a physician may have to focus on more immediate history, symptoms, and behavior to be able to make a management decision. In a scheduled visit, a more thorough assessment is appropriate.

Medical assessment of patients with mental symptoms seeks to identify 3 things:

  • Physical disorders mimicking mental disorders

  • Physical disorders caused by mental disorders or their treatment

  • Physical disorders accompanying mental disorders

Numerous physical disorders cause symptoms mimicking specific mental disorders (see table Selected Mental Symptoms Due to Physical Disorders). Other physical disorders may not mimic specific mental syndromes but instead change mood and energy.

Many drugs cause mental symptoms; the most common classes of drug causes are

Numerous other therapeutic drugs and drug classes have also been implicated; they include some classes that may not ordinarily be considered (eg, antibiotics, antihypertensives). Drugs of abuse, particularly alcohol, amphetamines, marijuana (cannabis), cocaine, hallucinogens, and phencyclidine (PCP), particularly in overdose, are also frequent causes of mental symptoms. Withdrawal from alcohol, barbiturates, or benzodiazepines may cause mental 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 mental symptoms in patients with a known mental disorder are due to that disorder.

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


Selected Mental Symptoms Due to Physical Disorders

Mental Symptom

Physical Disorder*

Confusion, delirium, disorientation

Cerebral arteritis, including that caused by SLE

CNS infection (eg, encephalitis, meningitis, toxoplasmosis)


Drug overdose, including prescription drug overdose

Electrolyte abnormalities

Mass lesion (eg, tumor, hematoma)

Thyroid disorders (eg, hypothyroidism)

Vascular infarct

Cognitive impairment, behavioral instability

Alzheimer disease and other degenerative cerebral disorders

Mass lesion


Thyroid disorders

Vascular infarct

Vitamin deficiency


Cancer treatments, including interferon

Dementing illnesses


Multiple sclerosis

Parkinson disease


Euphoria, mania

Brain tumor

CNS stimulant abuse

Cushing disease

Dementing illnesses

Huntington disease

Multiple sclerosis

Parkinson disease


Traumatic brain injury


Dyspnea or hypoxia



Multiple sclerosis

Memory impairment

Alcohol abuse

Cerebrovascular disease

Dementing illnesses


Huntington disease


Multiple sclerosis


Parkinson disease


Traumatic brain injury

Personality change

Cerebrovascular disease

Dementing illness






Mass lesion

Multiple sclerosis


Traumatic brain injury

Psychosis (eg,hallucinations, delusions)

Autoimmune encephalitis

Brain tumor

Cerebrovascular disease

CNS infections

Damage to the optic or vestibulocochlear nerve


Dementing illnesses


Fluid or electrolyte abnormalities

Huntington disease










Multiple sclerosis


Substance abuse


* In addition, numerous drugs and toxins may cause mental symptoms.

CNS = central nervous system; SLE = systemic lupus erythematosus.


Medical assessment by history, physical examination, and often brain imaging and laboratory testing (1) is required for patients with

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

  • Qualitatively different or unexpected symptoms (ie, in a patient with a known or stable mental disorder)

  • Mental symptoms that begin at an unexpected age

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


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, starting or stopping of a 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 known chronic physical disorders that can cause mental symptoms (eg, thyroid, liver, or kidney disease; diabetes; HIV infection). All prescription and over-the-counter drugs should be reviewed, and patients should be queried about any alcohol or illicit substance use (amount and duration). Family history of physical 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, particularly for signs of confusion or inattention.

A full physical examination is done, although the focus is on

  • 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 physical disorder. However, the converse is not true (ie, a clear sensorium does not confirm that the cause is a mental disorder). Other findings that suggest a physical cause include

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

  • Meningeal signs

  • Abnormalities noted during the neurologic examination, including aphasia

  • Disturbance of gait, balance, or both

  • 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 drug 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 mental disorder.

Symptoms that began shortly after significant trauma or after beginning a new drug may be due to those events. Drug or alcohol use may or may not be the cause of mental symptoms; about 40 to 50% of patients with a mental disorder also have a substance use disorder (dual diagnosis).


Patients typically should have

  • Pulse oximetry

  • Fingerstick glucose testing

  • Measurement of therapeutic drug levels

  • Urine drug screen

  • Blood alcohol level

  • Complete blood count

  • Urinalysis

If patients with a known mental disorder have an exacerbation of their typical symptoms and they have no medical complaints, a normal sensorium, and a normal physical examination (including vital signs, pulse oximetry, and fingerstick glucose testing), they do not typically require further laboratory testing.

Most other patients should have

Many clinicians also measure

  • Serum electrolytes (including calcium and magnesium), blood urea nitrogen, and creatinine

  • Erythrocyte sedimentation rate or C-reactive protein

Electrolyte and renal function tests may be diagnostic and help inform subsequent drug management (eg, for drugs that require adjustment in patients with renal insufficiency).

Other tests are commonly done based on specific findings:

  • Head CT: Patients with new-onset mental symptoms or with delirium, headache, history of recent 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

  • Thyroid function tests: Patients taking lithium, those with symptoms or signs of thyroid disease, and those > 40 years with new-onset mental symptoms (particularly females or patients with a family history of thyroid disease)

  • Chest x-ray: Patients with low oxygen saturation, fever, productive cough, or hemoptysis

  • Blood cultures: Seriously ill patients with fever

  • Liver tests: Patients with symptoms or signs of liver disease, with a history of alcohol or drug 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 is done if the patient has a recent history of substance abuse or physical signs suggesting intoxication or recent drug use (eg, needle marks).

Evaluation reference

  • 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.

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