Many tests and evaluation procedures are available that can be used to support and clarify initial diagnostic impressions.
Testing by a psychologist may measure intelligence and cognitive functioning; provide information about personality, feelings, psychodynamics, and psychopathology; and help differentiate functional problems from organic ones. The role of such tests is like that of other tests in medicine—helpful in diagnostic problems but may be an unnecessary expense and burden to the patient if the diagnosis is already clear.
These tests provide quantitative evaluation compared to standard norms.
The test most frequently used is the Wechsler Adult Intelligence Scale–Revised (WAIS-R). Intelligence tests often reveal more than IQ. The results, given expert interpretation, can quantify intellectual deterioration that has occurred.
B. MINNESOTA MULTIPHASIC PERSONALITY INVENTORY (MMPI-2)
The MMPI-2 is an empirically based test of personality assessment. The patient's scores are interpreted in comparison with data about others with the same response pattern to assess psychopathologic changes.
These tests include the Patient Health Questionnaire–9 (PHQ-9) and the Beck Depression Inventory (BDI), and Quick Inventory of Depressive Symptomatology-Self Report, 16 question (QIDS-SR16), self-administered diagnostic tools that can be used to screen for depression and can be useful in the primary care setting to inform and guide the need for further clinical assessment.
D. NEUROPSYCHOLOGICAL ASSESSMENT
Such an assessment is made when an organic deficit is present but information on extent and type of dysfunction is required.
These tests are unstructured, so that the patient responds in ways that reflect fantasies and individual modes of adaptation. They are particularly useful in identifying psychotic disorders and unconscious motivations.
A. RORSCHACH PSYCHODIAGNOSTICS
A type of projective test, this assessment utilizes ten inkblots to provide important information on psychodynamic themes and aberrations.
B. THEMATIC APPERCEPTION TEST (TAT)
This test uses 20 pictures of people in different situations to assess areas of interpersonal conflicts.
Consultation is often necessary and may include specialized tests. Brain imaging such as MRI, is used to detect potential structural abnormalities in the patient who presents with a nondefinitive history and examination (eg, dissociative episodes, unusual psychotic episodes not explained by drug abuse, or an acute change in mental status). Electroencephalography is useful for the diagnosis of seizure disorders and in differentiating delirium from depression or dementia. Typically, delirium is associated with generalized electroencephalographic slowing, while depression and dementia do not have this change. Single photon emission computed tomography (SPECT), functional MRI (fMRI), and positron emission tomography (PET) provide images of brain activity. These imaging modalities are used frequently in research and are opening new understandings of brain functioning.
C. General Laboratory Assessment
There are no well-established, specific laboratory assays for any psychiatric condition. However, the identification of specific biomarkers for neuropsychiatric conditions continues to evolve. There are commercially available assays that purport to facilitate the diagnosis of major depression and may help predict response to specific medications. For example, there are DNA cytochrome P450 tests available that are purported to increase the odds that a depressed patient will tolerate or respond to a given medication. However, additional studies, now underway, are needed to verify the usefulness of these laboratory tests.
There are many laboratory blood tests that are commonly used in medical practice that have an important role to play in the assessment and management of psychiatric conditions. In patients with depressive symptoms, a complete blood count and thyroid function tests may be indicated to determine whether anemia or hypothyroidism are contributing to symptoms of fatigue and malaise. Patients with schizophrenia taking antipsychotic agents generally need monitoring of blood glucose and lipid levels given the metabolic effects of these medications, while patients with bipolar disorder who receive lithium require monitoring of thyroid and kidney function on a regular basis.