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Brazilian Journal of Psychiatry

versão impressa ISSN 1516-4446versão On-line ISSN 1809-452X

Rev. Bras. Psiquiatr. vol.37 no.3 São Paulo jul./set. 2015

https://doi.org/10.1590/1516-4446-2014-1551 

Update Article

Functional capacity: a new framework for the assessment of everyday functioning in schizophrenia

Lucas M. Mantovani1  2 

Antônio L. Teixeira1  3 

João V. Salgado1  2  4 

1Graduate Program in Neurosciences, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil

2Instituto Raul Soares, Fundação Hospitalar do Estado de Minas Gerais (FHEMIG), Belo Horizonte, MG, Brazil

3Department of Internal Medicine, School of Medicina, UFMG, Belo Horizonte, MG, Brazil

4Department of Morphology, Instituto de Ciências Biológicas, UFMG, Belo Horizonte, MG, Brazil


ABSTRACT

Historically, measures of everyday functioning have focused exclusively on real-world performance. Despite the unquestionable value of “real-world functioning”, it has become clear that instruments for its assessment might not be as accurate as desirable. Functional capacity is a domain of everyday functioning that can be assessed through performance-based measures. In the last decade, functional capacity has become a cornerstone for the assessment of everyday functioning, since, alongside measures of real-world functioning, it provides a much more comprehensive picture of functional outcomes than any measurement alone. Functional capacity is more stable and less vulnerable to influence from environmental factors than other domains, and its correlation with cognitive functions has encouraged the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) project to suggest that a performance-based measure of functional capacity be included as a co-primary assessment of cognition in clinical trials. Functional capacity assessment instruments may be also useful in the evaluation of remission in schizophrenia. Validation of these instruments in different countries is desirable, and should always include cross-cultural adaptation; within large countries, adjustment for regional variations should be considered.

Key words: Schizophrenia; disability; everyday functioning; functional capacity; real-world functioning

Introduction

Schizophrenia is one of the most disabling conditions affecting young people around the world.1 It is currently defined by the presence of two or more of the following manifestations, lasting at least 1 month: delusions, hallucinations, disorganized thinking, grossly disorganized behavior, and negative symptoms.2

Subjects presenting with signs and symptoms of psychosis should be assessed along eight dimensions: the five aforementioned domains, cognition, depression, and mania.3 Schizophrenia also involves impairment in one or more major areas of functioning, with attenuated signs or symptoms of the disturbance persisting for at least 6 months.2 Despite the early descriptions of dementia praecox by Emil Kraepelin and of the fundamental symptoms of schizophrenia described by Eugen Bleuler4 in the early 20th century, assessment of the cognitive and functional impact of this disorder only became possible after pharmacological treatments were made available, allowing patients to live in the community and face the challenges of this environment. Furthermore, the fact that remission of psychotic symptoms does not usually entail improvement in social and occupational functioning was only recognized – and led to a shift in the focus on outcomes in schizophrenia – in the past 20 years.5

Achievement of the typical milestones of adulthood, such as keeping a job, raising a family, or maintaining a home, is strongly dependent on performance in the activities of daily living.6 The abilities to interact properly with others (social functioning), to deal with problems and issues at work (vocational functioning), and to perform activities such as paying bills or riding a bus (community functioning) constitute three of the main domains of what is known as everyday functioning. Patients with schizophrenia are less likely to achieve these functional goals than the general population.7

There are many reasons why someone may or may not succeed in the activities of everyday functioning. For instance, a lack of motivation to search for a job may be caused by several factors, including sociodemographic or environmental factors (such as high unemployment rates), slack financial resources, or even a reliance on disability benefits. Evidence also supports that high levels of negative8 and depressive9 symptoms in patients with schizophrenia have a negative impact on interpersonal skills. However, the best single predictor of functional outcome (everyday functioning or life milestones) seems to be cognition, which is especially impaired in schizophrenia.10

When studying the determinants of everyday functioning, it is very important to consider the difference between what a person is able to do (competence) and what they actually do (performance). The former is referred to as functional capacity, while the latter is known as real-world functioning. These constructs may be differently impacted by the determinants of everyday functioning outlined above. In recent years, a growing number of studies have focused on functional capacity,8,11-15 as this variable appears to be less dependent on nonspecific environmental factors and, as such, be more sensitive to therapeutic interventions. Hence, functional recovery after treatment in schizophrenia is more likely to be readily observed through measures of functional capacity than through real-world functioning, since changes in the latter domain usually take longer to manifest. Additionally, functional capacity is evaluated by the direct observation of patient performance in simulated real-life situations, and, as such, is less dependent on patient or caregiver reports and more closely related to patient cognition itself.16 The aim of this article is to review the topic of everyday functioning in schizophrenia, with an emphasis on the concept of functional capacity, its development, relevance, applicability to clinical trials, and utility in clinical practice.

Assessment of everyday functioning

Real-world functioning

Historically, measurements of everyday functioning have focused on the endpoint of real-world performance, in an attempt to classify level of disability on the basis of daily activities carried out improperly or not at all. The inclusion of one such instrument, the Global Assessment of Functioning (GAF), in the DSM-III-R17 illustrates the relevance of this topic in psychiatry at the end of the 20th century. Many instruments are currently available for the assessment of functioning.18 Some of these were designed to improve existing scoring patterns, while others refined the concept of functioning by dividing it into several subdomains. The Personal and Social Functioning (PSP)19 scale, for instance, measures four areas of functioning (socially useful activities; personal and social relationships; self-care; disturbing and aggressive behaviors) and, unlike the GAF, evaluates these domains independently from clinical symptoms. The Independent Living Skills Survey (ILSS)20 is composed of nine subdomains which focus on and describe specific issues relevant to real-world functioning, such as care of possessions, leisure activities, and transportation and job skills. Given that each of these instruments has distinct aims and evaluation criteria, a recent study sought to identify the most effective method for measuring functioning in clinical trials. This investigation, known as the Validation of Everyday Real-world Outcomes (VALERO)18 study, suggested that the six-domain Specific Level of Functioning (SLOF)21 scale provides the best assessment of real-world functioning in terms of reliability and sensitivity to change.

Despite the unquestionable value of “real-world functioning” measurements, the process of their assessment may not be as accurate as desirable, leading to wrong and incomplete conclusions concerning everyday functioning. Direct observation of behavior is still the optimal means of assessing functioning16,22; however, the time and expense required to observe subjects in all possible life situations makes it unfeasible. Collecting data from informants is a very useful and much more cost-effective procedure, and some instruments have versions designed specifically for this purpose, such as the ILSS.20 However, as many as one-third of patients do not have anyone who could serve as an informant,23 and not all informants, even among those considered “high contact,” seem equally informative.24 Self-report is probably the simplest way of assessing everyday functioning. As expected, however, poor insight,25 impaired cognitive functioning, and the presence of negative and depressive symptoms14 all contribute to poor self-evaluation and inaccuracy of the information provided.

Functional capacity

Performance-based measures are an ingenious strategy for the assessment of everyday functioning, and have several methodological advantages over measures of real-world functioning. Performance-based instruments were first developed for use in populations with cognitive impairment, such as those with Alzheimer’s disease.22 These tools evaluate functional behavior through role-playing tasks in a controlled environment, and, as such, are independent of patient insight and do not require the presence of an informant.16 As they are performed in controlled environments that may not correspond to the patient’s actual life demands, performance-based instruments are considered measures of functional capacity. In addition to predicting real-world functioning, these instruments provide a much more comprehensive assessment of everyday functioning than any single measure alone. Moreover, although there is no “gold-standard” measure of functioning, performance-based instruments appear to be more accurate than self-report measures in predicting important milestones, such as living independently or staying employed.26

Several performance-based assessments of functional capacity are currently available. The first such measure designed specifically for patients with schizophrenia was the University of California, San Diego, Performance-based Skills Assessment (UPSA),22 which encompasses five domains of community functioning: planning recreational activities, managing money, communicating, using public transportation, and household chores (preparing a shopping list). Subjects are asked to use props, such as real money or an unplugged telephone set, to demonstrate how they would perform each of these activities if they needed to in real life.

Since the UCSD was made available, many other instruments have been developed. The Social Skills Performance Assessment (SSPA)27 and the Maryland Assessment of Social Competence (MASC)28 rate social skills on the basis of performance in standardized role-plays – for instance, one requiring assertive communication with a landlord and another prompting the respondent to initiate a conversation with new co-workers. Competence to manage daily medication may be evaluated with the Medication Management Ability Assessment (MMAA).29 In this instrument, patients are given instructions as to the appropriate use of each of their medications and, after an interval, are asked to demonstrate the proper dosage and administration of each medication in a role-play scenario. The adaptive functioning domain can also be evaluated by performance-based measures, such as the Test of Adaptive Behavior in Schizophrenia (TABS).30 This instrument was designed to assess the patient’s ability to identify problems during the execution of a given task and change their strategy to achieve a proposed outcome. As in other similar instruments, this measure rates participant behavior during role-play situations. The Independent Living Scales (ILS) measure the cognitive skills required for independent living by assessing performance in five areas: memory/orientation, money management, managing home and transportation, health and safety, and social adjustment. In this instrument, subjects are asked to solve problems, demonstrate knowledge, or carry out specific tasks31 (Table 1).

Table 1 Performance-based measures of functional capacity 

Instrument Domain Props Administration time (minutes)
University of California, San Diego, Performance-based Skills Assessment (UPSA) Community activities Yes, many 30
Test of Adaptive Behavior in Schizophrenia (TABS) Adaptive behavior in community activities Yes, many 30
Independent Living Scales (ILS) Instrumental activities of daily living Yes, many 45
Social Skills Performance Assessment (SSPA) Social skills Yes, few 10
Maryland Assessment of Social Competence (MASC) Social skills Yes, few 30
Medication Management Ability Assessment (MMAA) Medication management Yes, some 15

The UPSA is the most widely used measure of functional capacity in the U.S., likely because it has good psychometric properties,12,32 is comprehensive, and requires no special training for administration or interpretation. The UPSA has already been adapted and validated for use in many countries around the world.33-38 A brief version of this instrument (UPSA-B), including two of the five original domains, has also been developed and demonstrated adequate psychometric properties.39

Over the last 10 years, the role of functional capacity in the complex process that leads to functional outcomes has been increasingly investigated. The significant association of functional capacity with cognitive function and its ability to predict real-world functional outcomes were taken into consideration by members of the NIMH-MATRICS project panel, who suggested that a performance-based measure of functional capacity and an interview-based measure of cognition be included as co-primary measures in their clinical trials.40 This proposal was clearly in agreement with Food and Drug Administration (FDA) requirements for the approval of any potential “cognitive-enhancing” drug, which were initially applied to studies of drugs seeking an indication for Alzheimer’s disease, but are now also mandatory for schizophrenia.

According to the FDA, changes in cognitive measures, as assessed by neuropsychological tests, must be accompanied by improvements which are relevant to both clinicians and consumers, thus demonstrating “face validity”. Real-world functioning measures were not taken into account, despite their high potential face validity, because changes in functioning may take too long to be detected in clinical trials. Additionally, demographic variables (e.g., disability benefits) may prevent any change at all in functional outcome, even when cognitive improvement is evident.41 In a study conducted to identify candidate instruments for this co-primary assessment, both the UPSA and MASC demonstrated good psychometric properties and were considered acceptable for this purpose, along with two interview-based scales.42 Ultimately, the MATRICS Co-Primary and Translation (MATRICS-CT) consortium launched the Validation of Intermediate Measures (VIM) Study, which selected the UPSA as the leading co-primary measure of functional capacity for use in clinical trials.43

Performance-based instruments are also being used in the validation process of many new interview-based cognition scales. The UPSA, for instance, was used in construct validation of the Schizophrenia Cognition Rating Scale (SCoRS)44 and, more recently, in the validation process of the Cognitive Assessment Interview (CAI), alongside the TABS.45 The VALERO study,18 conducted to evaluate functional rating scales, also included a measure of functional capacity (UPSA-B) in an attempt to identify the scale or scales most robustly related to performance-based measures of cognition and everyday living skills.

Relationship between functional capacity, everyday functioning, and related variables

Functional capacity has become a vitally important subdomain of everyday functioning, because of the growing body of evidence supporting its relationship with cognitive performance and real-world functioning, which it probably mediates to some extent.

Data on functional capacity support its strong correlation with cognitive function.46 More specifically, studies have found processing speed, episodic memory, and executive functions to be associated with community activities (as measured by UPSA), while working memory, episodic memory, and verbal fluency have been found to be more strongly associated with social competence (SSPA).47 Overall, it seems that working memory is the strongest single predictor of functional capacity, as measured by UPSA-B.15

Demographic factors such as age, gender, education, and ethnicity are significantly associated with performance-based measures of everyday functioning. Age and education, in particular, have been found to be strongly related to social competence, as evaluated by the SSPA.48 Subdomains of social cognition, such as theory of mind49 and the perception of negative emotions,50 also appear to mediate the relationship between cognitive functions and functional capacity, especially social skills (MASC).

Some evidence suggests that negative symptoms contribute directly to functional capacity,51 with negative impacts on the community (UPSA), social (SSPA), and medication management (MMAA) domains. The influence of negative symptoms on functional capacity has been found to be partially mediated by processing speed.52 Better abstract reasoning capacity is associated with higher scores in measures of functional capacity.53 This may be attributable to methodological factors, since performance-based instruments are essentially role-playing exercises.

Community skills, as measured by the UPSA, have been found to be associated with and predict with good accuracy the ability of patients with schizophrenia to live independently in the community.12 More specifically, UPSA score appears to be a good predictor of community responsibility, which includes activities such as household duties or paid employment, in community-dwelling patients.13,54

Functional capacity, as assessed by the UPSA, correlates moderately with real-world functioning,44 but there is good evidence to suggest that it may actually be a mediator between real-world functioning and neuropsychological factors.8,11 However, while everyday living skills appear to be the most important predictor of home functioning,12 blunted affect and passive-apathetic social withdrawal accounted for all variance in real-world social outcomes in a recent study,55 suggesting that these domains may be differently impacted by external factors.

Finally, an important corollary of these observations is that competence does not always translate into performance, even when cognition and skills are preserved. As expected, negative symptoms contribute to the gap between competence and performance,56 especially through subtle traits such as defeatist beliefs and lack of motivation.57 It appears that the dysfunctional attitudes56 described in cognitive theory, as well as low self-efficacy58 and depressive symptoms,7 also contribute negatively to the conversion of capacity into functioning.

The use of functional capacity measures in clinical trials

A PubMed search conducted by our research group in July 2014 using the keywords “functional capacity,” “functional competence” OR “functional ability” AND “schizophrenia” retrieved 164 articles, of which 10 reported on clinical trials of cognitive or functional enhancement using functional capacity scores as an outcome.59-68 While the first report meeting these criteria was published in 2006, most of the remaining articles were published in the last 3 years, probably after the aforementioned recommendations were implemented by the FDA. Five of these trials were designed to evaluate the effects of drug therapy with atypical antipsychotics (risperidone, quetiapine, lurasidone), a neuropeptide (davunetide), or other potential cognition-enhancing drugs. The remaining studies evaluated cognitive and functional remediation programs involving exercises for planning, problem-solving, and functioning skills, as well as cognitive training itself. The design and results of these clinical trials are summarized in Table 2.

Table 2 Summary of the experimental design and results of clinical trials having functional capacity as outcome 

Study Intervention Target variable of interest Design n Duration Patient diagnosis Measure of FC Conclusions
Bowie59 CR Functional competence Early vs. long- term course 39 12 weeks Schizophrenia SSPA, UPSA, and MMAA Treatment feasibility: both groups Clinical meaningful: early > long-term
Harvey60 DT Neurocognitive performance and functional capacity Lurasidone vs. quetiapine vs. placebo (DB) 267 6 weeks, 3 months, and 6 months Schizophrenia UPSA-B 6 weeks: no differences 3 months/6 months: lurasidone > quetiapine = placebo
Twamley61 CT Domains of cognition PhT alone vs. PhT + CT (RC) 69 12 weeks DSM-IV primary psychotic disorders UPSA Effects on attention, verbal memory and functional capacity: PhT + CT > PhT alone
Bowie62 CR Functional competence and real-world functioning CR vs. FAST vs. CR + FAST (RC) 107 12 weeks Schizophrenia SSPA and UPSA CR strongly enhanced neurocognition Improvements in functional competence: CR + FAST > CR or FAST alone
Javitt63 DT Cognition and functional capacity Davunetide vs. placebo (MC, DB, RC) 63 12 weeks Schizophrenia UPSA Effects on cognition: davunetide = placebo Effect on UPSA: davunetide > placebo
Velligan64 DT (AZD3490) Cognition AZD3490 vs. placebo (RC) 440 12 weeks Schizophrenia UPSA Effect on cognition and functional capacity: AZD3490 = placebo
Rodewald65 PPST or TBC Functional capacity PPST (computer- assisted) vs. TBC 89 10 sessions Schizophrenia O-AFP* Effect on functional capacity: PPST = TBC
Vesterager66 CT Cognitive and everyday functional capacity TaU vs. TaU + CT (MC, DB, RC) Enrollment ongoing Ongoing First-episode psychosis within F2 spectrum in ICD-10 UPSA-B Description of the development of a study protocol: results not yet published
Buchanan67 DT Cognitive impairment MK-0777 vs. placebo (MC, DB, RC) 60 4 weeks DSM-IV Schizophrenia UPSA Effects on cognitive impairment: MK-0777 > placebo (small effect)
Harvey68 DT Social competence and neuropsychological performance Quetiapine vs. risperidone (MC, DB, RC) 673 8 weeks Schizophrenia SSPA Improvements in social competence: quetiapine = risperidone Social competence correlates with neuropsychological measures

CR = cognitive remediation; CT = cognitive training; DB = double-blind; DT = drug trial; FAST = Functional Adaptation Skills Training; FC = functional capacity; MC = multicenter; MMAA = Medication Management Ability Assessment; O-AFP = Osnabrücker Arbeitsfähigkeiten Profil; PhT = pharmacotherapy; PPST = Planning and Problem-solving Training; RC = randomized controlled; SSPA = Social Skills Performance Assessment; TaU = treatment as usual; TBC = Training addressing Basic Cognitive functions; UPSA = University of California San Diego Performance-based Skills Assessment; UPSA-B = University of California San Diego Performance-based Skills Assessment, brief version.

*This instrument is only available in German and was therefore not mentioned in this review.

Future perspectives

Researchers and psychiatrists must make a serious effort to go beyond the relief of delusions and hallucinations in the treatment of schizophrenia, since this is a relevant, but insufficient outcome. True remission, in the current approach, should also include functional and cognitive outcomes.69 However, despite the availability and continued development of modern antipsychotics, psychosocial interventions, and cognitive training programs, there remains an enormous difference between the actual outcomes of “remitted” patients and what they could achieve based on their premorbid potential. Currently, real-world functioning may be problematic as a marker of recovery in schizophrenia, as many environmental factors may have a negative influence on and delay remission. Nevertheless, functional capacity instruments could address this issue and provide a safer, more readily assessed measure of clinical remission that takes everyday functioning into account.

The likely emergence of new drugs with effects on specific cognitive domains and their associated functional outcomes will require additional instruments validated for assessment of these domains. As it is unlikely that any single instrument will be able to cover all aspects of functioning impacted by clinical trials, researchers must choose the instrument that best matches their aims and hypothesis. Clinical trials of specific interventions for cognitive and functional remediation will also require functional assessment tools which are sensitive to change. As noted above, both existing and new versions of performance-based measures of functional capacity will certainly play a key role in this process.

All performance-based instruments available to date were developed in major cities of high-income, developed countries, i.e, the United States. The demands of everyday life in this setting and the skills required to meet them may differ from those experienced in smaller cities or rural areas, even within the United States itself. The UPSA, for instance, evaluates communication and transportation skills through proper use of a telephone set and interpretation of bus routes on a map. People living in small towns are unlikely to be familiar with bus maps, simply because this mode of transport is not a part of their everyday lives. Additionally, differences in cultural and educational background between subjects from developed and developing countries may also hinder translation during the validation process. Therefore, cultural adaptation is an essential part of the cross-cultural validation of functional capacity instruments, and should even be considered in the case of large countries with regional cultural variations.70,71 To our knowledge, the only developing country that has published data on the validation of a performance-based measure of functional capacity (UPSA) has been China. The strong influence of variations in educational levels across the sample led to a careful interpretation of scores on complex functional skills, such as banking and telephone usage, even among healthy participants.36

A recent review72 maintained that functional impairment is a candidate endophenotype for severe mental illness. The authors argued that measures of functional capacity are strongly related to neuropsychological performance and real-world outcomes, minimally affected by confounders such as symptoms and environmental features, and show similar scores across diverse populations and even different countries, such as the U.S. and Sweden.34 However, research into functional capacity and its genetic correlates in the prodromal stage of schizophrenia is still incipient, and no studies have investigated the familial nature of functional impairment.

In summary, over the past decade, functional capacity has become an essential domain for assessment of everyday functioning. Alongside actual real-world functioning, it provides a comprehensive picture not only of “what” patients can and cannot do, but also of “how” and “why”. The emergence of new treatment strategies targeting cognitive remediation will have a clear impact on functional capacity. The inclusion of a performance-based measure of functional capacity as a co-primary measure of cognition in the MATRICS batteries is a result of this conceptual change, and should encourage continuous improvement of the psychometric properties of existing instruments as well as the development of new and more specific measures and their validation for use in different settings and cultures. Lastly, the current approach of remission in schizophrenia demands the assessment of everyday functioning during the course of clinical follow-up, and functional capacity measures seem to be appropriate tools for this purpose.

References

1. World Health Organization (WHO). World Report on Disability [Internet]. 2011 [cited 2015 Feb 10]. http://www.who.int/disabilities/world_report/2011/report.pdfLinks ]

2. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Arlington: American Psychiatric Publishing; 2013. [ Links ]

3. Heckers S, Barch DM, Bustillo J, Gaebel W, Gur R, Malaspina D, et al. Structure of the psychotic disorders classification in DSM-5. Schizophr Res. 2013;150:11–4. [ Links ]

4. Andreasen NC. The evolving concept of schizophrenia: from Kraepelin to the present and future. Schizophr Res. 1997;28:105–9. [ Links ]

5. Harvey PD, Velligan DI, Bellack AS. Performance-based measures of functional skills: usefulness in clinical treatment studies. Schizophr Bull. 2007;33:1138–48. [ Links ]

6. Leung WW, Bowie CR, Harvey PD. Functional implications of neuropsychological normality and symptom remission in older outpatients diagnosed with schizophrenia: a cross-sectional study. J Int Neuropsychol Soc. 2008;14:479–88. [ Links ]

7. Sharma T, Antonova L. Cognitive function in schizophrenia Deficits, functional consequences, and future treatment. Psychiatr Clin North Am. 2003;26:25–40. [ Links ]

8. Bowie CR, Reichenberg A, Patterson TL, Heaton RK, Harvey PD. Determinants of real-world functional performance in schizophrenia subjects: correlations with cognition, functional capacity, and symptoms. Am J Psychiatry. 2006;163:418–25. [ Links ]

9. Rieckmann N, Reichenberg A, Bowie CR, Parrella M, White L, Friedman JI, et al. Depressed mood and its functional correlates in institutionalized schizophrenia patients. Schizophr Res. 2005;77:179–87. [ Links ]

10. Green MF, Kern RS, Braff DL, Mintz J. Neurocognitive deficits and functional outcome in schizophrenia: are we measuring the “right stuff”? Schizophr Bull. 2000;26:119–36. [ Links ]

11. Bowie CR, Leung WW, Reichenberg A, McClure MM, Patterson TL, Heaton RK, et al. Predicting schizophrenia patients' real-world behavior with specific neuropsychological and functional capacity measures. Biol Psychiatry. 2008;63:505–11. [ Links ]

12. Mausbach BT, Bowie CR, Harvey PD, Twamley EW, Goldman SR, Jeste DV, et al. Usefulness of the UCSD Performance-based Skills Assessment (UPSA) for predicting residential independence in patients with chronic schizophrenia. J Psychiatr Res. 2008;42:320–7. [ Links ]

13. Mausbach BT, Depp CA, Cardenas V, Jeste DV, Patterson TL. Relationship between functional capacity and community responsibility in patients with schizophrenia: differences between independent and assisted living settings. Community Ment Health J. 2008;44:385–91. [ Links ]

14. Sabbag S, Twamley EW, Vella L, Heaton RK, Patterson TL, Harvey PD. Predictors of the accuracy of self assessment of everyday functioning in people with schizophrenia. Schizophr Res. 2012;137:190–5. [ Links ]

15. Vesterager L, Christensen TØ, Olsen BB, Krarup G, Melau M, Forchhammer HB, et al. Cognitive and clinical predictors of functional capacity in patients with first episode schizophrenia. Schizophr Res. 2012;141:251–6. [ Links ]

16. McKibbin CL, Brekke JS, Sires D, Jeste DV, Patterson TL. Direct assessment of functional abilities: relevance to persons with schizophrenia. Schizophr Res. 2004;72:53–67. [ Links ]

17. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Third Revised Edition (DSM-III-R). Washington: American Psychiatric Association; 1987. [ Links ]

18. Harvey PD, Raykov T, Twamley EW, Vella L, Heaton RK, Patterson TL. Validating the measurement of real-world functional outcomes: phase I results of the VALERO study. Am J Psychiatry. 2011;168:1195–201. [ Links ]

19. Morosini PL, Magliano L, Brambilla L, Ugolini S, Pioli R. Development, reliability and acceptability of a new version of the DSM-IV Social and Occupational Functioning Assessment Scale (SOFAS) to assess routine social functioning. Acta Psychiatr Scand. 2000;101:323–9. [ Links ]

20. Wallace CJ, Liberman RP, Tauber R, Wallace J. The independent living skills survey: a comprehensive measure of the community functioning of severely and persistently mentally ill individuals. Schizophr Bull. 2000;26:631–58. [ Links ]

21. Schneider LC, Struening EL. SLOF: a behavioral rating scale for assessing the mentally ill. Soc Work Res Abstr. 1983;19:9–21. [ Links ]

22. Patterson TL, Qoldman S, McKibbin CL, Hughs T, Jeste DV. UCSD Performance-Based Skills Assessment: development of a new measure of everyday functioning for severely mentally ill adults. Schizophr Bull. 2001;27:235–45. [ Links ]

23. Patterson TL, Semple SJ, Shaw WS, Grant I, Jeste DV. Researching the caregiver: family members who care for older psychotic patients. Psychiatr Ann. 1996;26:772–84. [ Links ]

24. Sabbag S, Twamley EM, Vella L, Heaton RK, Patterson TL, Harvey PD. Assessing everyday functioning in schizophrenia: not all informants seem equally informative. Schizophr Res. 2011;131:250–5. [ Links ]

25. Gould F, Sabbag S, Durand D, Patterson TL, Harvey PD. Self-assessment of functional ability in schizophrenia: milestone achievement and its relationship to accuracy of self-evaluation. Psychiatry Res. 2013;207:19–24. [ Links ]

26. Mausbach BT, Moore R, Bowie C, Cardenas V, Patterson TL. A review of instruments for measuring functional recovery in those diagnosed with psychosis. Schizophr Bull. 2009;35:307–18. [ Links ]

27. Patterson TL, Moscona S, McKibbin CL, Davidson K, Jeste DV. Social skills performance assessment among older patients with schizophrenia. Schizophr Res. 2001;48:351–60. [ Links ]

28. Bellack AS, Brown CH, Thomas-Lohrman S. Psychometric characteristics of role play assessments of social skill in schizophrenia. Behav Ther. 2006;37:339–52. [ Links ]

29. Patterson TL, Lacro J, McKibbin CL, Moscona S, Hughs T, Jeste DV. Medication management ability assessment: results from a performance-based measure in older outpatients with schizophrenia. J Clin Psychopharmacol. 2002;22:11–9. [ Links ]

30. Velligan DI, Diamond P, Glahn DC, Ritch J, Maples N, Castillo D, et al. The reliability and validity of the Test of Adaptive Behavior in Schizophrenia (TABS). Psychiatry Res. 2007;151:55–66. [ Links ]

31. Revheim N, Medalia A. The independent living scales as a measure of functional outcome for schizophrenia. Psychiatr Serv. 2004;55:1052–4. [ Links ]

32. Leifker FR, Patterson TL, Bowie CR, Mausbach BT, Harvey PD. Psychometric properties of performance-based measurements of functional capacity: test-retest reliability, practice effects, and potential sensitivity to change. Schizophr Res. 2010;119:246–52. [ Links ]

33. Heinrichs RW, Statucka M, Goldberg J, McDermid Vaz S. The University of California Performance Skills Assessment (UPSA) in schizophrenia. Schizophr Res. 2006;88:135–41. [ Links ]

34. Harvey PD, Helldin L, Bowie CR, Heaton RK, Olsson AK, Hjärthag F, et al. Performance-based measurement of functional disability in schizophrenia: a cross-national study in the United States and Sweden. Am J Psychiatry. 2009;166:821–7. [ Links ]

35. Kaneda Y, Ueoka Y, Sumiyoshi T, Yasui-Furukori N, Ito T, Higuchi Y, et al. [Schizophrenia Cognition Rating Scale Japanese version (SCoRS-J) as a co-primary measure assessing cognitive function in schizophrenia]. Nihon Shinkei Seishin Yakurigaku Zasshi. 2011;31:259–62. [ Links ]

36. McIntosh BJ, Zhang XY, Kosten T, Tan SP, Xiu MH, Rakofsky J, et al. Performance-based assessment of functional skills in severe mental illness: results of a large-scale study in China. J Psychiatr Res. 2011;45:1089–94. [ Links ]

37. Helldin L, Cavallaro R, Galderisi S. A functional comparison of patients with schizophrenia between the North and South of Europe. Eur Psychiatry. 2012:27:442–4. [ Links ]

38. Garcia-Portilla MP, Gomar JJ, Bobes-Bascaran MT, Menendez-Miranda I, Saiz PA, Muãiz J, et al. Validation of a European Spanish-version of the University of California performance Skills Assessment (Sp-UPSA) in patients with schizophrenia and bipolar disorder. Schizophr Res. 2013;150:421–6. [ Links ]

39. Mausbach BT, Harvey PD, Goldman SR, Jeste DV, Patterson TL. Development of a brief scale of everyday functioning in persons with serious mental illness. Schizophr Bull. 2007;33:1364–72. [ Links ]

40. Buchanan RW, Davis M, Goff M, Green MF, Keefe RSE, Leon AC, et al. A summary of the FDA-NIMH-MATRICS workshop on clinical trial design for neurocognitive drugs for schizophrenia. Schizophr Bull. 2005;31:5–19. [ Links ]

41. Rosenheck R, Leslie D, Keefe R, McEvoy J, Swartz M, Perkins D, et al. Barriers to employment for people with schizophrenia. Am J Psychiatry. 2006;162:411–7. [ Links ]

42. Green MF, Nuechterlein KH, Kern RS, Baade LE, Fenton WS, Gold JM, et al. Functional co-primary measures for clinical trials in schizophrenia: results from the MATRICS Psychometric and Standardization Study. Am J Psychiatry. 2008;165:221–8. [ Links ]

43. Green MF, Schooler NR, Kern RS, Frese FJ, Granberry W, Harvey PD, et al. Evaluation of functionally meaningful measures for clinical trials of cognition enhancement in schizophrenia. Am J Psychiatry. 2011;168:400–7. [ Links ]

44. Keefe RS, Poe M, Walker TM, Kang JW, Harvey PD. The Schizophrenia Cognition Rating Scale: an interview-based assessment and its relationship to cognition, real-world functioning, and functional capacity. Am J Psychiatry. 2006;163:426–32. [ Links ]

45. Ventura J, Reise SP, Keefe RS, Hurford IM, Wood RC, Bilder RM. The Cognitive Assessment Interview (CAI): reliability and validity of a brief interview-based measure of cognition. Schizophr Bull. 2013;39:583–91. [ Links ]

46. Keefe RS, Poe M, Walker TM, Harvey PD. The relationship of the Brief Assessment of Cognition in Schizophrenia (BACS) to functional capacity and real-world functional outcome. J Clin Exp Neuropsychol. 2006;28:260–9. [ Links ]

47. McClure MM, Bowie CR, Patterson TL, Heaton RK, Weaver C, Anderson H, et al. Correlations of functional capacity and neuropsychological performance in older patients with schizophrenia: evidence for specificity of relationships? Schizophr Res. 2007;89:330–8. [ Links ]

48. Gould F, Bowie CR, Harvey PD. The influence of demographic factors on functional capacity and everyday functional outcomes in schizophrenia. J Clin Exp Neuropsychol. 2012;34:467–75. [ Links ]

49. Couture SM, Granholm EL, Fish SC. A path model investigation of neurocognition, theory of mind, social competence, negative symptoms and real-world functioning in schizophrenia. Schizophr Res. 2011;125:152–60. [ Links ]

50. Abram SV, Karpouzian TM, Reilly JL, Derntl B, Habel U, Smith MJ. Accurate perception of negative emotions predicts functional capacity in schizophrenia. Psychiatry Res. 2014;216:6–11. [ Links ]

51. Roseman AS, Kasckow J, Fellows I, Osatuke K, Patterson TL, Mohamed S, et al. Insight, quality of life, and functional capacity in middle-aged and older adults with schizophrenia. Int J Geriatr Psychiatry. 2008;23:760–5. [ Links ]

52. McDowd J, Tang TC, Tsai PC, Wang SY, Su CY. The association between verbal memory, processing speed, negative symptoms and functional capacity in schizophrenia. Psychiatry Res. 2011;187:329–34. [ Links ]

53. Savla GN, Twamley EW, Delis DC, Roesch SC, Jeste DV, Palmer BW. Dimensions of executive functioning in schizophrenia and their relationship with processing speed. Schizophr Bull. 2012;38:760–8. [ Links ]

54. Cardenas V, Mausbach BT, Barrio C, Bucardo J, Jeste D, Patterson T. The relationship between functional capacity and community responsibilities in middle-aged and older Latinos of Mexican origin with chronic psychosis. Schizophr Res. 2008;98:209–16. [ Links ]

55. Leifker FR, Bowie CR, Harvey PD. Determinants of everyday outcomes in schizophrenia: the influences of cognitive impairment, functional capacity, and symptoms. Schizophr Res. 2009;115:82–7. [ Links ]

56. Horan WP, Rassovsky Y, Kern RS, Lee J, Wynn JK, Green MF. Further support for the role of dysfunctional attitudes in models of real-world functioning in schizophrenia. J Psychiatr Res. 2010;44:499–505. [ Links ]

57. Green MF, Hellemann G, Horan WP, Lee J, Wynn JK. From perception to functional outcome in schizophrenia: modeling the role of ability and motivation. Arch Gen Psychiatry. 2012;69:1216–24. [ Links ]

58. Cardenas V, Abel S, Bowie CR, Tiznado D, Depp CA, Patterson TL, et al. When functional capacity and real-world functioning converge: the role of self-efficacy. Schizophr Bull. 2013;39:908–16. [ Links ]

59. Bowie CR, Grossman M, Gupta M, Oyewumi LK, Harvey PD. Cognitive remediation in schizophrenia: efficacy and effectiveness in patients with early versus long-term course of illness. Early Interv Psychiatry. 2014;8:32–8. [ Links ]

60. Harvey PD, Siu CO, Hsu J, Cucchiaro J, Maruff P, Loebel A. Effect of lurasidone on neurocognitive performance in patients with schizophrenia: a short-term placebo- and active-controlled study followed by a 6-month double-blind extension. Eur Neuropsychopharmacol. 2013;23:1373–82. [ Links ]

61. Twamley EW, Vella L, Burton CZ, Heaton RK, Jeste DV. Compensatory cognitive training for psychosis: effects in a randomized controlled trial. J Clin Psychiatry. 2012;73:1212–9. [ Links ]

62. Bowie CR, McGurk SR, Mausbach B, Patterson TL, Harvey PD. Combined cognitive remediation and functional skills training for schizophrenia: effects on cognition, functional competence, and real-world behavior. Am J Psychiatry. 2012;169:710–8. [ Links ]

63. Javitt DC, Buchanan RW, Keefe RS, Kern R, McMahon RP, Green MF, et al. Effect of the neuroprotective peptide davunetide (AL-108) on cognition and functional capacity in schizophrenia. Schizophr Res. 2012;136:25–31. [ Links ]

64. Velligan D, Brenner R, Sicuro F, Walling D, Riesenberg R, Sfera A, et al. Assessment of the effects of AZD3480 on cognitive function in patients with schizophrenia. Schizophr Res. 2012;134:59–64. [ Links ]

65. Rodewald K, Rentrop M, Holt DV, Roesch-Ely D, Backenstrass M, Funke J, et al. Planning and problem-solving training for patients with schizophrenia: a randomized controlled trial. BMC Psychiatry. 2011;11:73. [ Links ]

66. Vesterager L, Christensen TØ, Olsen BB, Krarup G, Forchhammer HB, Melau M, et al. Cognitive training plus a comprehensive psychosocial programme (OPUS) versus the comprehensive psychosocial programme alone for patients with first-episode schizophrenia (the NEUROCOM trial): a study protocol for a centrally randomised, observer-blinded multi-centre clinical trial. Trials. 2011;12:35. [ Links ]

67. Buchanan RW, Keefe RS, Lieberman JA, Barch DM, Csernansky JG, Goff DC, et al. A randomized clinical trial of MK-0777 for the treatment of cognitive impairments in people with schizophrenia. Biol Psychiatry. 2011;69:442–9. [ Links ]

68. Harvey PD, Patterson TL, Potter LS, Zhong K, Brecher M. Improvement in social competence with short-term atypical antipsychotic treatment: a randomized, double-blind comparison of quetiapine versus risperidone for social competence, social cognition, and neuropsychological functioning. Am J Psychiatry. 2006;163:1918–25. [ Links ]

69. Andreasen NC, Carpenter WT Jr, Kane JM, Lasser RA, Marder SR, Weinberger DR. Remission in schizophrenia: proposed criteria and rationale for consensus. Am J Psychiatry. 2005:162:441–9. [ Links ]

70. Harvey PD, Velligan DI. International assessment of functional skills in people with schizophrenia. Innov Clin Neurosci. 2011;8:15–8. [ Links ]

71. Velligan DI, Rubin M, Fredrick MM, Mintz J, Nuechterlein KH, Schooler NR, et al. The cultural adaptability of intermediate measures of functional outcome in schizophrenia. Schizophr Bull. 2012:38:630–41. [ Links ]

72. Harvey PD, McClure MM, Patterson TL, McGrath JA, Pulver AE, Bowie CR, et al. Impairment in functional capacity as an endophenotype candidate in severe mental illness. Schizophr Bull. 2012;38:1318–26. [ Links ]

Received: September 1, 2014; Accepted: January 14, 2015

Correspondence: Lucas M. Mantovani, Av. do Contorno, 3017, Santa Efigênia, CEP 30110-080, Belo Horizonte, MG, Brazil.E-mail: lmmantovani@gmail.com

Disclosure The authors report no conflicts of interest.

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