Even after training, experience, and self-reflection, the clinician’s reasoning is not perfectible. How can it be improved? No contemporary computer can match the skill of the expert clinician in recognizing and weighing cues and inferences, and assembling efficient patterns. However, computers excel at storing information, generating extensive arrays of hypotheses, calculating Bayesian probabilities, avoiding judgment biases, and ensuring that inquiry plans will be systematic. In the future, when base-rate probabilities are better understood, computers will become indispensable to accurate diagnosis and treatment planning. Self-report questionnaires, structured interviews, and search protocols could also enhance the reliability and comprehensiveness of data collection.
Flexible and efficient though diagnostic reasoning may be, it is subject to a number of errors that are a consequence of the fact that the human computer has inherent capacity limitations and is vulnerable to interference by intrinsic and extrinsic factors.
The Strategy of Clinical Reasoning
Diagnostic Reasoning is a feed-forward, feedback hypothetico-deductive process involving cue recognition, clinical inference, hypothesis testing, inquiry, planning, the search for evidence, the reaching of a diagnostic conclusion, and diagnostic formulation. In order to support the complexity of this process, the diagnostician must do several things (Table 9-3).
Research into Clinical Reasoning
There are three types of research into clinical reasoning: clinical judgment, decision theory, and process tracing. Clinical judgment research attempts to identify the criteria used by clinicians in making decisions. Decision theory explores the flaws and biases that deflect accurate clinical judgment. Process tracing elucidates the progressive steps of naturalistic reasoning. The first two types are statistical and prescriptive, the third is normative.
Clinical Reasoning & Actuarial Prediction
Diagnosis and treatment are risky ventures. They are fraught with the possibility of error that can have serious consequences. How can error be minimized? On the one hand are the clinicians who, having elicited information that is generally both incomplete and inferential, diagnose patients and use subjective probabilities to predict outcome. On the other hand are the psychological actuaries who regard natural clinical reasoning as so flawed as to be virtually obsolete and who seek to replace it with reliable statistical formulas.
Purpose of Clinical Reasoning
It is through clinical reasoning that clinicians collect, weigh, and combine the information required to reach diagnosis; decide which treatment is required; monitor treatment effectiveness; and change their plans if treatment does not work. The study of clinical reasoning, therefore, concerns the intellectual processes that underlie diagnosis and the planning and implementation of treatment.
Psychiatric Interview: Conclusion
The purpose of the psychiatric interview is to obtain information from the patient about the presenting problem and its precipitation and about previous disorders, predisposition, biopsychosocial strengths and limitations, reason for the current presentation, insight, and desire for help. The psychiatric history covers topics that range from identifying data to coping mechanisms. The four stages of the interview—inception, reconnaissance, detailed inquiry, and termination-are adapted to different topics.
Psychiatrists must increasingly rely on laboratory testing to confirm their diagnostic impressions, to detect medical or neurologic illness that may underlie or coexist with neuropsychiatric symptoms, and to ensure the safe and maximally effective use of certain psychotropic medications. Clinicians should understand the relevance of any laboratory test to the clinical problem presented by the patient and be ready to use the information obtained to enhance the findings of the psychiatric history and MSE.
Abnormalities of the Sense of Self
The normal person has a sense of selfhood composed of the following elements: a sense of existing and being involved in one’s own body and activity; a sense of personal continuity in time between past, present, and future; a sense of personal integrity; and a sense of distinction between self and outside world. In psychiatric disorders, any or several of these phenomena may be disturbed. For example, the individual may feel uninvolved in his or her own body or actions, like a spectator looking at another person (as in depersonalization); the individual’s sense of temporal continuity may be dislocated, with the past and future seeming remote and the present but a series of disconnected scenes; the individual’s ego may feel as though it is falling apart, shedding, fragmented, or split in two; or the difference between the self and other persons or objects may have become blurred.
Abnormal Preoccupations & Impulses
A phobia is a morbid and irrationally exaggerated dread that focuses on a particular object, situation, or act (see Chapter 22). Phobias differ from generalized anxiety in their focused quality; although a diffuse anxiety state sometimes precedes a phobic disorder. The patient is aware of the exaggerated, irrational nature of a phobia and regards it as symptomatic. The patient often tries to avoid the phobic situation or is compelled to perform actions (such as hand washing) in order to eradicate the object of the fear, or atone for tabooed action.
A delusion is a false belief that is not susceptible to argument and that is inconsistent with the subject’s sociocultural background. Bordering on delusion is the overvalued idea, a notion that may be eccentric rather than false but that becomes a governing force in the patient’s life.
It is not always easy to draw the line between an eccentric individual, somebody who holds unfamiliar views that are nevertheless consistent with a different sociocultural system, and a deluded person. Indeed, some people drift across the misty boundaries between these categories. An active delusion, however, is rigid, unshakable, and self-evident. It dominates the subject’s life, subordinating all other matters. It is private, idiosyncratic, ego-centered, and inconsistent with the common experience of people from the same background. A delusion, therefore, isolates the subject from others and alienates them from him or her.
Abnormalities of Thought Content
Several disorders are virtually defined by the presence of abnormalities of thought content. In many instances the patient will complain of these phenomena (eg, a phobia of heights); in other cases the patient appears to have accepted an eccentric idea (eg, the delusion of being a reincarnation of Christ) and to be acting accordingly. Abnormal thought may be divided into the following categories: abnormal perceptions, abnormal convictions, abnormal preoccupations and impulses, and abnormalities in the sense of self.
Components of the Mental Status Examination
Table 8-4 summarizes the areas to be covered in the MSE. The following sections describe these areas in more detail:
Types of Mental Status Examinations
Brief Screening Mental Status Examination
When a patient has been referred to an ambulatory clinic for a situational or personality problem, and none of the indications for a comprehensive screening examination pertain (see next section), a brief, informal screen is sufficient. The brief screening MSE is completed during the inception, reconnaissance, and detailed inquiry stages of the psychiatric interview.
Stages of the Psychiatric Interview
If the interviewer works in a clinic, at the opening of the psychiatric interview he or she goes to the waiting room, introduces himself or herself to the patient, accompanies the patient to the interview room, and shows him or her to a seat. After taking identifying data from the patient, the interviewer can tell the patient what he or she already knows. This approach avoids unnecessary mysteries and clears the way for action. Consider the following example: