Thinking Disorders Assessment

Introduction

Regardless of the instruments used, the clinical assessment of thought disorder must begin with clarification of the meaning of this illusive concept. ‘Thought disorder’ is a widely used and often misunderstood term with a history of confusion regarding the definition, underlying mechanisms, and diagnostic specificity. Following a presentation of a working definition of disordered thinking and a brief mention of various areas of conceptual confusion, I summarize categories of assessment instruments used to measure thinking disturbances.

Defining Thought Disorder

A comprehensive definition of thought disorder encompasses a broad perspective that includes not only traditional concepts such as impaired pace and flow of associations, but also such factors as [Page 1028]inefficient focusing and attentional processes; deviant word usage; errors in syntax and syllogistic reasoning; inappropriate levels of abstracting; failure to maintain conceptual boundaries; and a breakdown in the discrimination of internal perceptions from external ones. Such a definition captures the multidimensional nature of disturbances in thought organization (Kleiger, 1999).

Controversies, Problems, and Challenges

Measuring disordered thinking is beset with a number of controversies, potential problems, and challenges. Making inferences about an intangible variable such as thinking from overt speech is controversial and has led some to question the validity of the construct of ‘thought disorder’. Because the construct itself is called into question, instruments which purport to measure disordered thinking, instead of disordered speech, for example, are vulnerable to the criticism that they lack sufficient construct validity to justify claims of their effectiveness as diagnostic tools.

Another difficulty that plagues assessment effort is the lack of universal agreement over what constitutes disordered thought. There is general agreement that disordered thinking occurs in a variety of conditions, falls along a continuum of severity, and reflects a number of different anomalies in thinking. However, there is no absolute standard for classifying these anomalies of thought. Furthermore, different researchers often employ different techniques to assess different types of disturbed thinking. Although there may be overlap in many of the variables studied by different assessment methods, comparison between the various techniques is often difficult. Different assessment approaches may employ different names for similar variables or use the same name for essentially different types of disordered thinking.

Achieving sufficiently high inter-rater reliability or clinical sensitivity with the instruments is a challenge since many of the ratings or scoring systems themselves can be quiet intricate, difficult to learn, and subject to interpretation. Research on the most prominent scales and scoring systems demonstrates that significantly high inter-rater reliability is possible; however, learning some of these rating systems usually requires more than familiarizing oneself with the manuals. Often consultation with the researchers, who pioneered the ratings scales or scoring systems, is necessary in order to use the instruments competently.

The impact of phase of illness, medication, and context must be taken into consideration when assessing disordered thinking. The degree to which an individual's thinking is disorganized will depend on whether she/he is in an acute phase, or in a partial or complete remission. Valid measurement of disordered thinking also requires one to evaluate the subject's motivation, attitude, the context in which the idiosyncratic thinking is revealed. Is the subject aware of the bizarreness of his or her speech or ideas and, if so, what is their attitude toward it? Is idiosyncratic speech used to shock, control, or entertain? The presence of unusual ideas or odd speech does not constitute immediate grounds for inferring the incursion of a psychotic process.

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