Medical assessment of patients with mental symptoms seeks to identify 3 things:
Numerous physical disorders cause symptoms mimicking specific mental disorders (see Table 2: 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, 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 a 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.
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 inanition resulting from chronic psychosis) or its treatment (eg, hypothyroidism due to lithium, hyperlipidemia secondary to atypical antipsychotics).
Medical assessment by history, physical examination, and often brain imaging and laboratory testing is required for patients with
The goal 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 abused 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 OTC 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.
Vital signs are reviewed, particularly for fever, tachypnea, hypertension, and tachycardia. Mental status is assessed (see Examination of Mental Status), 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), and 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—see 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
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) suggest anticholinergic drug effects. Constricted pupils suggest opioid drug effects or pontine hemorrhage. Rotary or vertical nystagmus suggests PCP intoxication, and horizontal nystagmus often accompanies diphenylhydantoin toxicity. Garbled speech or inability to produce speech suggests a brain lesion (eg, stroke). A preceding history of relapsing-remitting neurologic symptoms, particularly when a variety of nerves appear to be involved, suggests multiple sclerosis or vasculitis. Stocking-glove paresthesias may indicate 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 abuse may or may not be the cause of mental symptoms; about 40 to 50% of patients with a mental disorder also have substance abuse (dual diagnosis).
Patients typically should have
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
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:
Less often, findings may suggest testing for SLE, syphilis, demyelinating disorders, Lyme disease, or vitamin B12 or thiamin deficiency, especially in patients presenting with signs of dementia.
Last full review/revision December 2012 by Caroline Carney Doebbeling, MD, MSc
updates.last-modified August 2013