Psychotic Patients

Diagnostic Evaluation

It cannot be stressed enough that the presence of psychotic symptoms does not always mean that a primary psychiatric disorder like schizophrenia is present. Therefore, the diagnostic assessment of a psychotic patient begins with a thorough consideration of toxic or medical conditions that can present with psychosis ( Table 12-1 ). A medical history, review of systems, family history, and physical examination are crucial elements of this process because most organic causes can be identified on this basis. A bedside examination of cognitive function should be performed. The Mini-Mental State Examination supplemented by the clock-drawing test will usually suffice as an initial cognitive screen. Serious deficits in attention, orientation, and memory suggest delirium or dementia rather than a primary psychotic illness. However, only more comprehensive neurocognitive testing will establish the more subtle yet functionally relevant cognitive difficulties with processing speed, working memory, verbal memory, and executive function that almost all patients with schizophrenia, including first-episode patients, experience to some degree. Careful delineation of the temporal course of psychotic symptoms is of particular diagnostic importance. History from family about the patient is often the most critical aspect for piecing together how the illness unfolded over time. One should consider whether the disorder is chronic, episodic, or of recent onset. A typical prodromal period of unspecific anxiety and depression for several months followed by attenuated psychotic symptoms and increasing role failure that eventually gives rise to psychosis at the syndromal level is a typical time course for beginning schizophrenia. The temporal relationship of psychotic symptoms to mood episodes, substance use, medication use, and medical or neurologic illness should be carefully reviewed. Substance misuse, such as intoxication with stimulants or synthetic cannabinoids, is potentially reversible and in the latter case an increasingly common cause of psychosis that leads to emergency room visits. Many other illegal drugs and legal medications have the potential to cause psychosis; unfortunately, causality is often difficult to prove ( Table 12-2 ). Such substance-induced psychoses should be considered if the psychosis is of new onset, if there is no personal history of psychosis, or if the psychosis starts in the hospital, particularly if a delirium is present. A urine toxicologic screening test might identify unsuspected drug use, but it would not rule out drug-induced psychosis if it were negative, nor would a positive toxicologic screening test necessarily establish a cause for the psychosis, because co-morbid substance use and abuse is common in psychotic disorders. Many designer drugs that are freely available over the Internet require specialized and dedicated testing that is usually not available. Routine laboratory testing includes determination of a sedimentation rate, a complete blood cell count, serum electrolytes, urinalysis, and levels of calcium, glucose, creatinine, and blood urea nitrogen. In addition, liver function tests, thyroid function tests, and syphilis serology (specific, such as the fluorescent treponemal antibody absorption test), are appropriate. Human immunodeficiency virus (HIV) testing should be recommended. Extended work-ups may include karyotyping for chromosomal abnormalities or urine testing for metabolic disorders. The diagnostic yield from neuroimaging of the brain (magnetic resonance imaging, MRI; or computed tomography, CT) is low in the absence of localizing neurologic findings. Neuroimaging should be obtained, however, in cases with atypical or unresponsive psychotic symptoms when psychotic symptoms first appear and should be considered even in cases with typical psychotic features, because the long-term costs and morbidity of this disorder are potentially quite high in relation to the expense of diagnostic procedures. The electroencephalogram (EEG) can be useful when evaluating a confused patient where a delirium is suspected or when a history of serious head trauma or symptoms suggestive of a seizure disorder are present. An EEG is rarely helpful if it is employed as a routine screening procedure. Similarly, a lumbar puncture is not necessary for a routine work-up, but it can be lifesaving if a treatable central nervous system (CNS) infection is suspected. NMDA receptor encephalitis is a newly delineated autoimmune disorder of particular concern to psychiatrists since patients might initially present with only psychiatric symptoms. Making this diagnosis quickly is critical to initiate immunotherapy and requires a lumbar puncture to detect NMDA receptor antibodies.

Several neuropsychiatric disorders in particular should be considered during the diagnostic work-up of a patient with psychosis. Huntington's disease is suggested by family history of Huntington's disease, dementia, and choreiform movements; psychotic symptoms may occur before motor and cognitive symptoms become prominent. Parkinson's disease also may present with psychosis, along with bradykinesia, tremor, rigidity, and a festinating gait. With disease progression, psychosis is common and can be the result of illness and not just of medications. The diagnosis of Parkinson's disease can be complicated by exposure to neuroleptics—review of the time course of neurologic symptoms in relation to the use of antipsychotics should clarify this diagnostic possibility. Wilson's disease may also present with psychotic symptoms, tremor, dysarthria, rigidity, and a gait disturbance. Kayser–Fleischer rings, which are golden-brown copper deposits that encircle the cornea, are pathognomonic for this disease. However, a slit-lamp exam is needed to detect them early on. The diagnosis can be confirmed by measuring concentrations of ceruloplasmin in the urine and serum. Finally, acute intermittent porphyria is characterized by acute episodes of abdominal pain, weakness, and peripheral neuropathy; this condition may be associated with psychosis. Because this is a hereditary (autosomal dominant) illness, a family history often points to this diagnosis. During acute attacks, levels of δ-aminolevulinic acid and porphobilinogen are elevated in the urine.

It is impractical and ill-advised to attempt to rule out all conceivable diseases that could cause psychosis. The more tests are ordered without clinical concern for a particular disease, the more false-positive test results will occur. Thankfully, a thoughtful approach that combines clinical history and a physical examination (including a neurologic examination) with selected laboratory tests will usually suffice to exclude treatable medical illnesses and provide a medical baseline for future reference. Table 12-3 suggests one screening battery that accomplishes these important initial diagnostic goals.

After an organic cause has been ruled out, the psychiatric differential diagnosis of psychosis flows from the diagnostic criteria contained in the “Psychotic Disorders” section of the Diagnostic and Statistical Manual of Mental Disorders , 5th edition (DSM-5). It should be emphasized, however, that these criteria are guidelines for diagnosis and a tool for a common language; they are to be used only in conjunction with a full understanding of the descriptions of the syndrome as described in textbooks ( Table 12-4 ). A clear, longitudinal view of the illness is necessary to identify affective episodes and to determine whether the patient's level of function has declined. In addition, the range and severity of psychotic and negative symptoms as well as the neurocognitive impairment must be determined. Psychotic patients are often unable to provide an accurate history; therefore information must be collected from as many sources as possible. In one study, information necessary for diagnosis, such as the presence of persecutory delusions, was missed more than 30% of the time when the assessment was based on the interview only. Concurrent substance abuse is also frequently missed in patients with schizophrenia if toxicologic screening is not performed.