Dr. Lindenmayer is clinical professor in the Department of Psychiatry at New York University School of Medicine and clinical director of the Manhattan Psychiatric Center in New York City.
Disclosures: Dr Lindenmayer receives grant support from AstraZeneca, Azur, Bristol-Myers Squibb, Eli Lilly, the National Institute of Mental Health, Janssen, Organon, and Pfizer; and is consultant to Eli Lilly and Janssen. This manuscript was sponsored by Johnson & Johnson.
Please direct all correspondence to: Jean-Pierre Lindenmayer, MD, Clinical Director, Manhattan Psychiatric Center, New York, NY 10035; Tel: 646-672-6004; Fax: 646-672-6446; E-mail: Lindenmayer@NKI.RFMH.org.
• Impaired patient function is a core component of schizophrenia.
• Improving patient functioning is an important treatment goal.
• Scales that assess function should be used routinely in clinical practice.
Functional impairment is observed in the majority of patients with schizophrenia and is now considered a core diagnostic feature of the disorder. Nonetheless, patient function has been a neglected aspect of the burden of schizophrenia. Despite the availability of numerous assessment scales, patient functioning has not been routinely assessed in clinical practice or as a major outcome in clinical trials. This article highlights the independence of functioning from the psychopathologic features of schizophrenia and its interference with patient recovery even when effective symptom control is achieved. This article details the complexity of measuring patient functioning and the need for increased use of assessment scales in clinical practice, in particular those scales that can assess functioning independent of the symptoms of schizophrenia. The ease of use of such scales should also help to promote their routine use in the attainment of improving patient function and, therefore, improving the long-term prognosis for patients with schizophrenia.
Schizophrenia is a chronic disease encompassing a range of symptoms including hallucinations, delusions, social withdrawal, and anhedonia. Symptom control has been a major goal of schizophrenia treatment. Different measurement tools, such as the Positive and Negative Syndrome Scale (PANSS), the Clinical Global Impressions–Severity (CGI-S) scale, and the Brief Psychiatric Rating Scale (BPRS) are utilized to assess the symptoms of schizophrenia.
Schizophrenia symptoms have a measurable impact on many aspects of a patient’s life. Severe deficits in functioning are observed in daily living, family life, social interactions and employment. This article highlights both the importance of improving patient functioning as part of the overall treatment approach to schizophrenia and how the assessment of this aspect of the disease has been neglected in clinical practice and as a major outcome of clinical trials despite its importance in optimizing long-term prognosis. Also emphasized is the complexity of measuring patient functioning; its independence from and overlap with the psychopathologic features of the disease; and how the development of scales that can assess functioning independently of symptoms are necessary for the progression and assessment of new treatment options.
Improving Patient Functioning: An Important Treatment Goal
The importance of functioning in patients with schizophrenia was acknowledged in 1980 with its formal inclusion as one of the five axes of patient clinical status in the Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM-III)1 classification system, which was retained in the subsequent DSM-IV.2 Deficits in functioning are now described as one of the defining characteristics of schizophrenia in the DSM-IV-TR,3 broadly depicting changes in functioning in terms of work, interpersonal relations, and self care. Impairments in patient functioning can lead to decreased medication adherence, increased risk of hospitalization, and diminished ability to either engage in relationships or to maintain employment, which can further impact the disease progression. Moreover, schizophrenia is associated with considerable economic burden due to the loss in productivity as well as the costs of treatment, hospitalization, and rehabilitation.
Patient functioning is partly affected by the phase of the disease. Treatment expectations vary between individuals, but during the acute phase, they include improvement in the domains that impact basic functioning and everyday living (eg, aggressive behavior, paranoia, and the basics of self care). In stable phases, expectations of functional improvement encompass more autonomous social behavior, the ability to actively participate in rehabilitative therapy, and better functioning at work. Improvement in these domains may enable the patient to partake in relationships and increase employment opportunities.
Assessment of functioning is complex and has been a neglected aspect of the stable phase of schizophrenia. However, with each successive relapse the likelihood of patients regaining their previous level of functioning is compromised. Conversely, with persistent symptom control there is the potential for functional improvement. However, there is recognition that impairment in the symptom domains of schizophrenia is not always related to decreases in functioning. Indeed, there is increased awareness that functioning must be assessed independently of and in addition to the symptoms of schizophrenia to improve long-term treatment outcomes for the patient.
Specific functional deficits have been linked to various symptom domains of the disease, such as negative symptoms and certain cognitive impairments (eg, nonverbal social perception, attention and memory, executive functioning, and concept formation). Specifically, some studies have shown that negative symptoms have consistent associations with social problem solving and inconsistent relationships with community functioning but not with skill acquisition.4 It has been suggested that the level of cognitive functioning may predict subsequent functional outcome in the community setting, and that there may be links between cognitive deficits, autonomous living, and sustained employment.5 However, the overall concept of functioning as an outcome of schizophrenia can be independent of the psychopathology of the disease; the relationship between psychotic symptoms and social functioning is not linear and improvements in symptoms do not always result in functional improvements.4
Assessment of Patient Functioning in Schizophrenia
How Can We Routinely Assess Functioning in Schizophrenia?
Clinical trials that have assessed patients’ functioning have utilized various scales, including those based on the DSM-IV, and have measured different aspects/domains of functioning. Many have not been validated in schizophrenia and were not designed for use in this population. Quality of life (QOL) is generally considered an important outcome measure in schizophrenia, and scales for the assessment of QOL have been used as a measure of functioning in many studies, even though many of these scales are not considered sensitive to the specific impact of schizophrenia on functioning.6 Scales include the Lehman Quality of Life Interview,7,8 Social Function Scale,9 Strauss-Carpenter Level of Functioning scale (SLOF),10 Quality of Well-being Scale,11 the Medical Outcomes Study Short Form-36,12 Independent Living Skills Inventory,13 and the University of California, San Diego Performance-based Skills Assessment.14
The measurement of functioning is complicated by the type of assessment used. Patient-reported assessments are regarded as necessary to provide an accurate representation of the outcome. This is especially relevant in terms of the subjective impact of treatment, particularly with respect to functioning. However, self-assessments have been shown to be unrelated to observer-rated symptom scale assessment in patients with schizophrenia. Nevertheless, patients have rated improvement in functioning as an important outcome in their treatment expectations, confirming that their opinion is valuable and should be taken into consideration. It may be argued that subject-rated outcomes are not necessarily reliable, as patients might not be able to assess or accurately report their condition owing to the inherent nature of the symptoms, including psychosis, cognitive deficits, and reduced insight. Additionally, little evidence exists in the literature regarding the reliability and validity of self-reports from patients with acute schizophrenia. Clinician-rated scales, although considered more accurate due to rating by a trained professional and generally validated, also have disadvantages: training for application of the scale is required and there is the possibility of some subjectivity of scoring by the clinician. Another complication in the assessment is the need to have an outside source available to obtain information the clinician may not have direct access to, such as work functioning, peer functioning in settings outside the clinician office, and performance of activities of daily living. This information can often only be obtained by a person who is very familiar with the day-to-day functioning of the patient. However, it may be difficult to have family members, case workers, or staff from board and care homes available at the time of the assessment by the clinician in the outpatient setting, which may be another reason why assessments of functioning are not always part of routine clinical practice.
Scales for Assessment of Patient Functioning in Schizophrenia
Given the present interest on those assessment instruments, which may be particularly helpful for clinical practice, this evaluation will be limited to instruments with a more global scope. Of these scales available to measure functioning in schizophrenia, those based on the DSM-IV criteria are considered to be the most clinically meaningful to clinicians and researchers and will, therefore, be the focus of this article. These clinician-rated instruments include the Global Assessment of Functioning (GAF) scale, the Social and Occupational Functioning Assessment Scale (SOFAS), and the Personal and Social Performance (PSP) scale.
The GAF has demonstrated good sensitivity to change and disorders with higher complexity; higher levels of severity are associated with lower scale scores. As one of the most frequently used scales, the GAF only assesses global functioning in terms of a single rating of overall psychological, social, and occupational functioning,15 and consequently, interpretation of specific aspects of patient functioning is difficult. The revised GAF has demonstrated improved inter-rater reliability as compared with the original GAF but considers only social and occupational functioning. There is evidence that this revised scale is more strongly related to psychiatric symptoms than to the functional capacity of the patient.16
The SOFAS, developed by the American Psychiatric Association for the DSM-IV to operationalize functioning, improved on the GAF by incorporating the impact of psychological and general medical symptoms on patient functioning.17 Although this expanded the assessment beyond a single axis and improved the ability to measure functioning independent of the severity of psychiatric symptoms, the SOFAS has been criticized for poor linguistic distinction of terms such as “serious” and “major” impairment.
The newer PSP scale18-20 has been developed as a further improvement over the GAF and SOFAS, demonstrating good reliability and validity in patients with severe mental illness in an inpatient rehabilitation program and a stable outpatient population. Unlike the SOFAS, the PSP scale specifies four areas to be rated, enabling the clinician to specifically identify where patients are impaired within the spectrum of these four functional domains that are representative of the spectrum of functioning in schizophrenia (Table).2,15-21 A single-scale rating based on these four domains can also be independently assessed. Unlike the GAF and SOFAS, the PSP scale has demonstrated an ability to measure a functional construct of the disease, showing greater correlation with SLOF than the moderate correlations with the symptom-oriented PANSS or CGI-S scale.18 Furthermore, sensitivity to change of the PSP scale has been demonstrated after treatment interventions. A change on the PSP scale has been correlated with changes in symptomatology on the CGI-S and PANSS total scales pointing to some degree of relationship between this measure of functioning and psychotic symptoms. No significant psychometric limitations of the scale have been identified, although validation assessment was only conducted over a 7-day period and, therefore, longer-term validation studies are required. Additionally, studies are necessary to determine the effect of differing amounts of information provided by patients and clinicians on PSP ratings. User-friendly training materials for the PSP scale should be developed to increase its use by non-research clinicians and practitioners.
Although used increasingly in clinical trials, scales of functioning are not routinely used in clinical practice for the assessment of schizophrenia. While some clinicians are beginning to use symptom rating scales such as the CGI-S or the BPRS, the use of scales such as the PANSS may be limited due to their demanding and time-consuming nature. Consistent use of functional assessment scales in clinical practice remains suboptimal.
In order to facilitate achieving more wide-reaching outcomes in schizophrenia, scales that assess patient functioning relatively independent of the disease psychopathology should be more routinely included in clinical practice. The development of schizophrenia-specific measures that reflect the improved understanding of the impact of functional deficits on the patient and the phase of the disease could provide the basis for such scales to become more widely used, allowing assessment of functioning as the disease progresses or patients improve. This will allow practitioners to focus on and to include treatment interventions that specifically target domains of impaired functioning that otherwise might be neglected. In today’s busy clinical practices, shorter and simpler scales that can be administered by different treatment team members beyond the treating psychiatrist will be more likely to be adopted for routine use. This will allow the treatment team to assess whether functional treatment goals are being reached, ultimately raising expectations for long-term prognosis and potentially promoting a more widespread acceptance of such measures.
The impaired functioning exhibited by patients with schizophrenia can impact many aspects of life. Thus, for antipsychotic and rehabilitative treatments to be considered fully effective, they should not only target symptom improvement, but also improvements in patient functioning that may be independent of the psychopathology of the disease. The routine measurement of functioning with accessible scales should increase awareness of patients’ levels of functioning and improvements following treatment. User-friendly scales shown to reliably assess functional domains independent of disease symptoms should have optimal utility and be useful across all phases of schizophrenia. The ease of use of such scales should also help to promote their routine use with the aim of focusing and improving patient function and, therefore, advancing the long-term prognoses for patients with schizophrenia. Ultimately, this should help raise expectations of treatment outcomes. PP
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