Tools to Assess Negative Symptoms in Schizophrenia
John M. Kane, MD
Department of Psychiatry, The Zucker Hillside Hospital, Glen Oaks; the Department of Psychiatry, Hofstra North Shore-Long Island Jewish School of Medicine, Uniondale; and Behavior Health Services, North Shore-Long Island Jewish Health System, New Hyde Park, New York
Negative symptoms, such as anhedonia, asociality, avolition, affective flattening, and alogia, are a critical unmet need in the treatment of schizophrenia. Bobes et al1 found that almost 60% of treated patients with schizophrenia had 1 or more negative symptoms, of whom 13% had primary negative symptoms. Because of the proven impact of negative symptoms on patient functioning, clinicians need to be able to assess, diagnose, and address these symptoms. Unfortunately, antipsychotic agents are more effective in treating positive rather than negative symptoms. The lack of treatment options for negative symptoms can create a sense that measuring them is less important than measuring positive symptoms. However, accurate assessment can improve clinical care by aiding physicians in the following ways:
- fully evaluating and documenting the patient’s baseline level of illness severity to measure treatment response at follow-up
- providing treatment goals to work toward
- allowing for systematic outcome evaluations
- documenting quantitative assessments in a consistent and reliable fashion
AV 1. The Importance of Using Assessment Scales in Clinical Practice (00:36)
Achieving interrater reliability, or consistency among clinicians in performing an assessment, is challenging with negative symptoms because of their multidimensionality.2 Although the average clinician may not use quantitative assessment instruments in day-to-day clinical practice, the field should begin to move in that direction. Without quantitative assessments, making careful and informed clinical judgments is difficult ().
The following overview of current and future assessment tools provides a reference for clinicians to understand the complex dimensions of negative symptoms and how their categorization has changed over time. These tools are appropriate to use in clinical practice and are not too burdensome or time consuming to implement for each patient visit.
Current Assessment Tools
Clinical Global Impressions scale (CGI). Rather than being a symptom checklist, the widely used CGI3 is a brief clinician-rated instrument for overall assessment. The original version (CGI-S), which takes less than a minute, asks the clinician to rate the severity of the patient’s mental illness based on the clinician’s judgment.4 The CGI-I can be used to track patients’ global improvement resulting from treatment.5 Another element, the Efficacy Index, asks the clinician to rate the medication benefits in the context of adverse effects.
The CGI has been criticized for its lack of standard scoring definitions, but this gives the clinician flexibility to personalize each patient’s assessment.4 The CGI is sensitive to change and correlates well with more complex scales. Because the CGI is concise and simple, it has been used effectively in clinical practice and in schizophrenia studies.5
The CGI-SCH scale6 was developed to assess positive, negative, depressive, and cognitive symptoms and overall severity in schizophrenia. The CGI-SCH evaluates the severity of illness based on the previous week and the degree of change due to treatment as compared with the previous evaluation. Its simplicity and quick administration time make it appropriate for use in routine clinical practice and in observational studies.
Brief Psychiatric Rating Scale (BPRS). The BPRS7 was designed to assess symptomatic change during the course of treatment in psychiatric patients and to provide a description of the 16 major symptom characteristics of psychosis. The clinician rates each symptom on a 7-point Likert-type scale (from “not present” to “extremely severe”) based on clinical observation and patient report. The BPRS takes 2 to 3 minutes for the experienced clinician to administer the scale questions, following the recommended 18-minute patient interview. The BPRS addresses emotional withdrawal and blunted affect but fails to assess anhedonia and asociality.2
Positive and Negative Syndrome Scale (PANSS). The PANSS8 is a 30-item, 7-point rating scale based on 18 items from an updated BPRS and 12 items from the Psychopathology Rating Schedule. Designed to standardize positive and negative symptom assessment, the PANSS includes a detailed definition of each symptom item and its rating (from “absent” to “extreme”), takes 35 to 50 minutes to complete, and requires minimal training to conduct. The clinician compiles information from the patient interview and feedback from family members or primary care staff.
The PANSS includes a 7-item positive symptom subscale, a 7-item negative symptom subscale, and a 16-item general psychopathology subscale.8 The negative symptom subscale specifically assesses blunted affect, emotional and social withdrawal, and poor rapport; however, some items now appear to address cognitive functioning (eg, abstract thinking deficit, stereotyped thinking, and poverty of speech).9 The PANSS helps the clinician consider positive and negative symptoms relative to one another and to the general illness severity.
Scale for the Assessment of Negative Symptoms (SANS). The clinician-rated 20-item SANS10 globally evaluates affective flattening, anhedonia-asociality, attention, alogia, and avolition-apathy. To enhance reliability, these symptoms feature a general description and each domain is divided into observable behaviors (eg, lack of vocal inflections, physical anergia) and measured on a 6-point scale (from “none” to “severe”). The SANS is a valid and reliable tool to assist clinicians in assessing and separating negative symptoms from positive and depressive symptoms in patients with schizophrenia.11
The SANS has shown a moderate correlation with the negative symptom subscale of PANSS, indicating that both scales measure similar constructs of schizophrenia. Rabany et al11 supported the validity of the SANS factors, although they suggested relocating or omitting “poor eye contact” from the affective flattening subscale and moving “grooming and hygiene” from the avolition factor to the alogia factor to improve internal consistency.
16-Item Negative Symptom Assessment (NSA-16). The NSA-1612 uses a 5-factor model to describe negative symptoms: (1) communication, (2) emotion/affect, (3) social involvement, (4) motivation, and (5) retardation. These factors, assessed through a structured interview, are comprehensive and well-defined to help standardize assessment. As a truncated version of the 26-item NSA, the NSA-16 still captures the multidimensionality of negative symptoms but can be completed in about 15 to 20 minutes. Axelrod and Alphs12 discovered that raters unfamiliar with NSA-16 were able to assess negative symptoms at an expert level after one 30-minute training session. Standardized measurement of negative symptoms was also achieved in international trials, further supporting the validity of NSA-16.13
The SANS and the NSA-16 both provide a focused assessment of negative symptoms, but they must be used in conjunction with a positive symptom rating scale.
Future Assessment Tools
Two new tools for assessing negative symptoms, the CAINS and the BNSS, are being developed as a result of the NIMH-MATRICS Consensus Development Conference on Negative Symptoms. The Collaboration to Advance Negative Symptom Assessment in Schizophrenia (CANSAS) project14 is a multisite study that is developing and testing the following new scales.
Clinical Assessment Interview for Negative Symptoms (CAINS). The CAINS15 measures the severity of 5 consensus-based negative symptoms: asociality, avolition, anhedonia (consummatory and anticipatory), affective flattening, and alogia. The CAINS is a semi-structured, 7-point, 23-item interview with extensive prompts and follow-up questions to elicit reactions for each item, as well as clear anchors for ratings.15 To best understand behavioral deficits and make the most informed clinical assessment, the clinician considers behavior along with environmental context and patient self-reports.14
With a beta version of the CAINS, preliminary findings showed satisfactory internal consistency reliability and promising interrater agreement. Because this assessment tool is still undergoing analysis, the 5 domains could change, and the final structure could be different than the one presented here.
AV 2. Anhedonia Presentation in Patients With and Without Schizophrenia (00:31)
Brief Negative Symptom Scale (BNSS). The BNSS16 was created to address the same 5 negative symptom domains included in the CAINS as well as distress, but it is a concise instrument intended for use in clinical as well as treatment-trial settings. Thirteen items are organized into 6 subscales, and a clinician can administer the BNSS in about 15 minutes.16
The BNSS has a manual of instructions and definitions, a workbook to use when interviewing the patient, and a score sheet.
Like the CAINS, the BNSS incorporates the latest schizophrenia research, such as distinguishing between anticipatory versus consummatory aspects of anhedonia ()17 and internal experience versus behavior.
The BNSS total score was highly correlated with both the SANS and the PANSS negative symptom subscale scores, suggesting that this new instrument assesses a similar underlying construct.16 The BNSS also showed excellent interrater reliability with relatively brief training for the raters.
Compare the Assessment Tools
While assessment tools can help clinicians evaluate and track negative symptoms, clinicians need to determine whether the negative symptoms are primary or secondary. Negative symptoms can be secondary to positive symptoms, result from other conditions like depression or demoralization, or appear to be antipsychotic-induced extrapyramidal side effects.
A diagnostic tool called the Schedule for the Deficit Syndrome (SDS)18 provides specific criteria for assessing whether negative symptoms are primary or secondary. Through a semi-structured interview, the clinician determines the presence and duration of negative symptoms and then categorizes patients with schizophrenia into those with and those without the deficit syndrome.9 Patients with the deficit syndrome must have at least 2 negative symptoms, not caused by other conditions or drug effects, which have been continually present for 12 months.19 These patients require unique treatment, which makes the SDS relevant in assessing, diagnosing, and managing patients with schizophrenia.
For more information on negative symptom presentation, see the Psychlopedia activity by Stephen R. Marder, MD, “Clinician Perceptions, Expectations, and Management of Negative Symptoms in Schizophrenia.”
Many assessment tools are available for clinicians to document the baseline severity of negative symptoms and to systematically track symptomatic improvement and treatment response in their patients. The CGI is a useful starting point in obtaining the larger clinical picture, but it must be combined with more specific scales. The BPRS and the PANSS assess specific factors encompassing positive, negative, and cognitive symptoms. To measure just the negative symptoms of schizophrenia, the SANS and NSA-16 help the clinician track treatment progress and symptom severity. The CAINS and BNSS were created specifically for negative symptoms of schizophrenia and reflect recent consensus- and evidence-based research, but they are still in early development and are not yet available for clinical use. For help differentiating between primary and secondary negative symptoms, clinicians may use the SDS to assess and track the cause of negative symptoms.
Because some patients are unable to give an accurate account of their activities, clinicians should also try to obtain information from family members, friends, and/or caregivers. This additional perspective is a valuable resource for the clinician. By learning and using an appropriate assessment tool, clinicians will be better equipped to provide measurement- and evidence-based care to help patients achieve their goals.
- Choose an appropriate assessment scale to regularly track the severity and treatment response of negative symptoms in your patients with schizophrenia
- Obtain patient information from as many sources as possible, including caregivers, family members, and friends
- Rule out negative symptoms that are secondary to other conditions and medication side effects
BNSS = Brief Negative Symptom Scale, BPRS = Brief Psychiatric Rating Scale, CAINS = Clinical Assessment Interview for Negative Symptoms, CANSAS = Collaboration to Advance Negative Symptom Assessment in Schizophrenia, CGI = Clinical Global Impressions, CGI-I = CGI-Improvement, CGI-S = CGI-Severity, CGI-SCH = CGI-Schizophrenia, MATRICS = Measurement and Treatment Research to Improve Cognition in Schizophrenia, NSA = Negative Symptom Assessment, PANSS = Positive and Negative Syndrome Scale, SANS = Scale for the Assessment of Negative Symptoms, SDS = Schedule for the Deficit Syndrome
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