Diagnostic Concepts in the Context of Clinical High Risk/Attenuated Psychosis Syndrome

There are several overlapping definitions of clinical high risk (CHR) that evolved from the application of schizophrenia prodrome concepts to early detection with the goal of secondary prevention of a psychotic disorder. The definitions vary in meaningful ways,¹ but each presumes that individuals so identified merit clinical care for current symptoms and impaired function. When the psychopathology progresses to full psychosis, the diagnosis may be clarified—usually in the schizophrenia spectrum in the studies to date.² For many people, however, the diagnostic picture is less clear at the outset. Individuals with CHR symptoms have a range of mental health concerns that extend beyond psychosis and warrant mental health services.^3–5 Given the range of potential outcomes, what is the appropriate clinical categorization for people who have not yet and may never progress to full psychosis? How is the range of psychopathology observed in these individuals to be conceptualized and classified?

Attenuated Psychosis Syndrome (APS) placed in Section 3 of Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V) for further study is one option. This, or one of the other CHR definitions, provides a “place holder” diagnostic category where ultimate diagnosis is expected to emerge overtime but where evidence-based detection and intervention are required in the present. It can be argued that clinical care should be provided to youth with CHR symptoms, but specifying “risk symptoms” does not meet obligations when a diagnostic code is required. Nor does it facilitate evidence-based care, and clinical trials to date show promise for symptom reduction and secondary prevention of full psychosis.⁶ The advantages of establishing a diagnostic class to capture CHR individuals has been presented^7,8 and counter arguments have also been provided.⁹

What, at present, are the viable alternatives for classification of patients with CHR symptoms? At least 4 approaches can be implemented in the context of current classification, each with strengths and limitations. First is to use a V code for “other conditions that may be a focus of clinical attention.” There are many V codes, each capturing a specific situation that fails to address central aspects of presenting psychopathology, and has no relationship to research developed with the CHR concept. Too much is known about CHR for this sort of pseudospecific classification. A second option is to use one of the existing disorder classes such as 300.02 Generalized Anxiety Disorder or 296.21 Major Depressive Disorder, but this approach fails to capture the specific risk symptoms central to the CHR concept. This approach will prove valid for some over time, but will miss important current symptomatology, and places the CHR concept in a diagnostic construct that is not compatible with the existing scientific evidence.² The established mood and anxiety disorders are intended to capture disorders, not temporary descriptors of symptoms that occur with many different disorders. A third approach may be to extend beyond a single diagnostic class to use co-morbid diagnoses in an attempt to capture the entire whole (eg, an anxiety disorder for anxiety, a sleep-wake disorder for disturbed sleep pattern, a depressive disorder for depressed mood). This option defines the various psychopathologies present in each individual as independent phenomena without a parsimonious or overarching concept and does not provide adequate consideration of the psychotic-like experiences. In psychotic disorders, for example, the presence of depression or anxiety is not considered an independent, comorbid disorder, but rather is expected and compatible with the overarching concept. These 3 options fail to give emphasis to the psychosis-like symptoms central to the CHR construct.

A fourth option provided in DSM-5 is within Other Specified Schizophrenia Spectrum and Other Psychotic Disorder 298.9, where Attenuated Psychosis Syndrome is listed as an example. This option has some advantages, but ultimately is part of a heterogeneous category where individuals outside the CHR concept would be included and would only be informative in circumstances where the APS is made explicit.

Three things seem evident:

• CHR is a heterogeneous syndrome and any diagnostic approach will result in later reclassification for most people;

• Clinical care must address psychopathology and function specific to each individual regardless of diagnosis; and

• Classification must facilitate translation of CHR research into clinical care of persons for whom the research is relevant.

Outside of the existing classification system, the idea of a new diagnostic category as a “place-holder” has appeal. Although not without its limitations, at a practical level, such a category can make explicit that individuals vary substantially in both present needs and ultimate diagnostic classification. At a conceptual level it can facilitate integration of information across psychopathology domains rather than viewing each symptom as independent.

Accepting that none of the potential approaches to CHR conceptualization is without problems, 4 considerations provide a basis for resolving this dilemma in favor of a new diagnostic class.

• 1. CHR research provides strong validation for classification with a range of variables where results are not compatible with alternative diagnostic classes.²

• 2. The initial treatment trials support interventions that reduce current symptoms, may improve function, and are effective in secondary prevention of psychosis.⁶ Translation of evidence-based care onto CHR individuals in general clinical practice requires a systematic approach to identification.

• 3. Regardless of diagnostic approach there will be many individuals who are on the path to psychosis, some with stable features overtime that meet criteria for other disorders (eg, mood, anxiety, and personality disorders), and others that may recover and the diagnostic issue is never clarified.

• 4. A place-holder diagnosis is explicit in requiring time for diagnostic clarification.

A sense of urgency is needed as the field approaches this issue. Clinical services are expanding rapidly and in advance of systematic application of science. There is an immediate need for the following:

• 1. A consensus view from experts as to diagnostic concept and criteria;

• 2. Documentation that diagnosis can be reliably accomplished in ordinary clinical settings and guidelines as to the necessary educational process to assure translation of research to clinical care; and

• 3. Clinical trials of interventions that relate broadly to psychopathology in order to establish optimal approaches to the range of symptoms, functional impairments, and quality of life as well as secondary prevention of psychosis.