The differential diagnosis is best approached by organizing the information obtained in the psychiatric evaluation into five domains of mental functioning according to the disturbances revealed by the evaluation. After organizing the in-formation into these five domains, the psychiatrist looks for the psychopathological syndromes and potential diagnoses that best account for the disturbances described. A complete diagnostic evaluation includes assessments on each of the five axes of DSM-IV-TR (Table 19.22).
Disturbances of consciousness, orientation and memory are most typically associated with delirium related to a general medical condition or a substance use disorder. Memory impair-ment and other cognitive disturbances are the hallmarks of de- etiology. It is important to elicit risk factors for HIV infection and, when they are present, to encourage voluntary HIV anti-body testing. Neuropsychological testing is particularly useful in the diagnosis of subcortical dementia, such as that caused by Huntington’s disease and HIV infection. Dissociative disorders and severe psychotic states may also present with disturbances in this domain without evidence of any medical etiology. Cognitive impairment caused by mental retardation is established by intel-ligence testing.
Disturbances of speech, thinking, perception and self-experience are common in psychotic states that can be seen in patients with such diagnoses as schizophrenia and mania, as well as in central nervous system dysfunction caused by substance use or a medical condition. Disturbances in self-experience are also common in dissociative disorders and certain anxiety, somato-form and eating disorders. Cluster A personality disorders may be associated with milder forms of disturbances in this domain (American Psychiatric Association, 2000).
Disturbances of emotion are most typical of affective and anxiety disorders. These disturbances may also be caused by substance use disorders and general medical conditions. Mood and affect disturbances accompany many personality disorders and may be especially pronounced in borderline personality disorder.
Physical signs and symptoms and any associated abnor-malities revealed by diagnostic medical tests and past medical history are used to establish the presence of general medical con-ditions, which are coded on Axis III. When a medical disorder is causally related to a psychiatric disorder, a statement of this re-lationship should appear on Axis I. Physical signs and symptoms may also suggest diagnoses of mood or anxiety disorders or states of substance intoxication or withdrawal. Physical symptoms for which no medical etiology can be demonstrated after thorough assessment suggest somatoform or factitious disorders or malin-gering, although the possibility of an as-yet-undiagnosed medical condition should still be kept in mind.
Information about behavior and adaptive functioning is useful for diagnosing personality disorders, documenting psychosocial and environmental problems on Axis IV, and as-sessing global functioning on Axis V. This information is also useful for diagnosing most psychiatric disorders, which typically include criteria related to abnormal behaviors and functional impairment.
When all information has been gathered and organized, it may be possible to reach definitive diagnoses, but sometimes this must await further evaluation and the development of the comprehensive treatment plan.
The initial treatment plan follows the case formulation, which has already established the nature of the current problem and a tenta-tive diagnosis. The plan distinguishes between what must be ac-complished now and what is postponed for the future. Treatment planning works best when it follows the biopsychosocial model.
This includes an immediate response to any life-threatening medical conditions and a plan for the treatment of other less acute physical disorders, including those that may contribute to an al-tered mental status. Prescription of psychotropic medications in accordance with the tentative diagnosis is the most common bio-logical intervention.
This includes immediate plans to prevent violent or suicidal be-havior and address adverse external circumstances. An overall strategy must be developed that is both realistic and responsive to the patient’s situation. Developing this strategy requires an awareness of the social support systems available to the patient; the financial resources of the patient; the availability of services in the area; the need to contact other agencies, such as child wel-fare or the police; and the need to ensure child care for dependent children.
The primary task of the initial disposition is to select the most ap-propriate level of care after completion of the psychiatric evalua-tion. Disposition is primarily focused on immediate goals. After referral, the patient and the treatment team develop longer term goals.
The first decision in any disposition plan is whether hospitaliza-tion is required to ensure safety. There are times when a patient presents with such severe risk of harm to self or others that hos-pitalization seems essential. In other cases, the patient could be managed outside the hospital, depending on the availability of other supports. This might include a family who can stay with the patient or a crisis team in the community able to treat the patient at home. The more comprehensive the system of services, the easier it is to avoid hospitalization. Because hospitalization is associated with extreme disruption of usual life activities and in and of itself can have many adverse consequences, plans to avoid hospitalization are usually appropriate as long as they do not compromise safety.
These interventions provide ongoing supervision but at a lower level than that available within the hospital. They are most often used to treat patients with alcohol and substance use disorders or severe mental illness. Crisis housing can be useful when a patient cannot safely return home, when caregivers need respite, and when the patient is homeless. Other forms of supervised hous-ing usually have a waiting period and may not be immediately available.
There are many different types of and names for day-long programming, including partial hospitalization, day treatment, psychiatric rehabilitation and psychosocial clubs. Depending on the nature of the program, it may provide stabilization, daily medication, training in social and vocational skills, and treatment of alcohol and substance use problems. Long-term day programs should generally be avoided if a patient is functioning successfully in a daytime role, such as in a job or as a homemaker. In these instances, referral to a day program may promote a lower level of functioning than the patient is capable of.
The most common referral after psychiatric evaluation is to psy-chotherapy and/or medication management. In office-based set-tings, the psychiatrist decides whether she or he has the time and expertise to treat the patient and makes referrals to other practi-tioners as appropriate. Hospital staff usually have a broad over-view of community resources and refer accordingly. There are high rates of dropout when patients are sent from one setting to another. These can be reduced by providing introductions to the treatment setting and/or conducting follow-up to ensure that the referral has been successful.
The psychiatric evaluation usually continues beyond the ini-tial disposition. The providers assuming responsibility for the patient, who may be inpatient staff, outpatient staff, or private practitioners, complete the evaluation and take responsibility for developing the comprehensive treatment plan. This plan covers the entire array of concerns that affect the course of the patient’s psychiatric problems. In hospital settings, the initial treatment plan is usually completed within 24 to 72 hours after admission, followed by comprehensive treatment plan after more extensive evaluation.
The comprehensive treatment plan usually includes more definitive diagnoses and a well-formulated management plan with central goals and objectives. For severely ill or hospitalized patients, every area is usually covered (Table 19.23 and 19.24). It is best for the patient and, as appropriate, the family, to have input into the plan. The comprehensive treatment plan guides and coor-dinates the direction of all treatment for an extended time, usually
months, and is periodically reviewed and updated. For more focal psychiatric problems (e.g., phobias, sexual dysfunctions) and more limited interventions (e.g., brief interpersonal, cognitive, and be-havioral therapies in office-based practices), the comprehensive treatment plan may focus on only several of the possible areas.