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The Importance of Cognition in the Conceptualization of both Dementia and Severe Mental Illness in Older People
EDITORIAL
The Importance of Cognition in the Conceptualization of both Dementia and Severe Mental Illness in Older People Elizabeth W. Twamley, Ph.D., Philip D. Harvey, Ph.D.
I
n the July/August 2004 issue of the American Journal of Geriatric Psychiatry, Dr. Barton Palmer’s introduction to the theme of Neuropsychology discussed the expanding role of neuropsychology in geriatric psychiatry.1 This issue’s theme is Cognition, which focuses less on the localization of cognitive impairment in the brain and more on the importance of cognition in understanding disease states. Cognitive impairment has long been understood as the hallmark of degenerative dementias such as Alzheimer disease, of course, but our understanding of the cognitive components of severe mental illness is still developing, as is our appreciation of the nature and strength of the linkage between cognition and the functional outcomes that are important to patients and their families. Psychiatric disorders, brain disorders that they are, are increasingly being conceptualized as having significant cognitive components. The empirical articles in the American Journal of Geriatric Psychiatry during 2005, for example, addressed cognition not only in Alzheimer disease, but also in stroke2 and anxiety and depression.3,4,5,6 The impact of cognition on function in both healthy elders and psychiatric populations also was highlighted.7,8,9 All of the severe mental illnesses appear to feature significant cognitive impairment along with psychiatric symptoms. Interestingly, these cognitive impairments are generally not a function of the other aspects of the illness, as striking as these features may be. Schizophrenia has increasingly been conceptualized as a cognitive disorder producing psychosis, rather than a psychotic disorder affecting cognition.10
The neuropsychological deficits of schizophrenia occur in multiple domains, including attention, working memory, learning, memory, processing speed, and executive functioning, and are relatively stable over time.11,12,13 The cognitive impairments seen in affective disorders, too, are increasingly being viewed as central to the illness, rather than mere epiphenomena.14 Bipolar disorder patients, even when in euthymic states, have cognitive deficits that are qualitatively and quantitatively similar to those seen in schizophrenia.15 Depression, too, has long been associated with cognitive dysfunction comparable to that seen in both bipolar disorder and schizophrenia.16 In one study of stable outpatients, schizophrenia and bipolar subjects did not differ on 9 of 10 neuropsychological tests administered17; in another study of chronically institutionalized patients, there were no overall differences between patients with schizophrenia, unipolar depression, and bipolar disorder on an 11-test cognitive assessment, while 18/30 PANSS items differed between the groups.18 As is the case in bipolar disorder and schizophrenia, the cognitive impairments of depression are seen even in stable outpatients.19 Both unipolar depressed and bipolar patients show deficits in verbal learning and memory consistent with an encoding deficit.14,20,21 The public health significance of cognitive functioning in older people cannot be understated. Better recognition of Alzheimer disease in its earliest state, for example, would have profound social and financial effects. Cognitive impairment also is a leading cause of disability in severe mental illness, often even
From the Department of Psychiatry, University of California, San Diego, San Diego, California (EWT); and the Department of Psychiatry, Mount Sinai School of Medicine, New York, New York (PDH). © 2006 American Association for Geriatric Psychiatry
Am J Geriatr Psychiatry 14:5, May 2006
387
Editorial more so than psychiatric symptoms.22,23,24 Further, functional recovery is much rarer than development of sustained symptomatic remission, with cognitive deficits predicting persistent functional disability. The articles in this special theme issue on Cognition are varied in their emphasis on basic versus clinical research and in their populations of study. The topics range from phenomenology to diagnosis, treatment, and prognosis. The uniting theme of Cognition, however, highlights the importance of understanding cognitive ability in order to fully understand both dementia and severe mental illness in older people. In the first article in this theme section, Moore and colleagues25 investigated the cognitive underpinnings of persecutory delusions in very late onset schizophrenia-like psychosis (SLP). Using both a probabilistic reasoning task and two tasks of social cognition, they found that patients with SLP differed from comparison subjects only on a task involving detection of deception by other people. They did not show deficits on the probabilistic reasoning task, assessing the tendency to jump to conclusions, or a pattern of externalizing blame for negative events (both common in younger schizophrenia patients). These findings illuminate the types of thinking errors that might lead to a fairly circumscribed symptom picture of persecutory delusions in SLP. Tatsch and colleagues26 investigated neuropsychiatric symptoms in a community-based sample of Brazilian elders with Alzheimer disease or Cognitive Impairment No Dementia (CIND). Both groups had significant levels of neuropsychiatric symptoms, including sleep disturbance, anxiety, and depression. However, over half of the Alzheimer disease group had significant apathy, whereas only 12% of the CIND group did. Furthermore, as cognitive impairment (as rated by the Clinical Dementia Rating scale) increased among the Alzheimer disease subjects, apathy became increasingly prominent. Thus, apathy and cognitive impairment may share a common substrate, perhaps frontal system impairment, in Alzheimer disease. The following article, by Brodaty and colleagues,27 concerns dementia screening in primary care. Early detection of Alzheimer disease, the most common cause of dementia, could result in earlier pharmacologic treatment and delayed nursing home placement, thus reducing the cost of Alzheimer disease care (currently estimated at $100 billion per year in
388
the US28). Additionally, early and accurate diagnoses aid patients and family members in health care decision-making. It makes sense that large-scale screening for Alzheimer disease will be necessary as the population grows older; such screening will most effectively take place in primary care settings. Brodaty and colleagues reviewed several brief, simple screening instruments that could be used by primary care physicians. Although they identified no perfect measure, they recommended the General Practitioner Assessment of Cognition (GPCOG), Mini-Cog, and Memory Impairment Screen (MIS) as being the three best. All three measures were comparable to the MMSE in terms of classification accuracy, but take less than five minutes to administer. Continuing the Alzheimer disease story, van Dyck and colleagues29 examined different definitions of treatment response in the context of a 24-week randomized controlled trial of memantine in moderateto-severe stage Alzheimer disease patients who were stabilized on donepezil. In this secondary analysis of the Tariot et al. trial,30 van Dyck and colleagues considered three definitions of treatment response: 1) cognitive improvement from baseline, 2) improvement or lack of decline in one of the primary outcomes (cognition, independence in activities of daily living, clinician’s impression of change, and neuropsychiatric symptoms), and 3) improvement or lack of decline in multiple primary outcomes. Compared to placebo, memantine treatment resulted in significantly higher response rates using the first two definitions of treatment response, and was statistically superior to placebo on six of the possible 10 combinations of multiple outcomes. The final two articles present complementary longitudinal investigations of cognitive impairment and late-life depression, and address important questions of prognosis in this population. Using comprehensive neuropsychological assessments, Bhalla and colleagues31 found that 30% of their unipolar depressed patients were cognitively impaired at baseline. Of this 30%, 94% continued to be cognitively impaired one year later, although their depression was remitted. Thus, cognition did not improve even with effective treatment of depression. They also found that among the 70% of patients who were cognitively intact at baseline, 23% were cognitively impaired at one-year follow-up, even though their depression was remitted. Thus, depression without cognitive
Am J Geriatr Psychiatry 14:5, May 2006
Twamley and Harvey impairment was a risk factor for future cognitive impairment one year later. In the final article of the Cognition section, Steffens and colleagues32 reported data from a large-scale, two-year, multisite trial addressing the question of cognition and treatment outcomes in late-life depression. Memory impairment, measured by three-item recall and three orientation questions, was present in 35% of the patients. Baseline memory impairment did not affect depression treatment outcomes, but memory decline during the two-year trial resulted in worse depression treatment outcomes. Both articles on cognitive impairment in late-life depression suggest that both conditions should be treated simulta-
neously in order to prevent further cognitive decline and to improve depression outcomes. The six articles comprising this special section on Cognition illustrate just a few of the ways in which cognition is relevant in geriatric psychiatry. The growing understanding of cognition as a “rate limiting step” in functional improvement with treatments of these illnesses makes imperative the further study of cognition not only in dementia, but also in other severe mental illnesses. Thus, further interdisciplinary research involving the fields of neuropsychology, cognitive neuroscience, and geriatric psychiatry will continue to illuminate diagnosis and treatment issues in geriatric psychiatry.
References 1. Palmer BW: The expanding role of neuropsychology in geriatric psychiatry. Am J Geriatr Psychiatry 2004; 12:338–341 2. Vataja R, Pohjasvaara T, Ma¨ntyla¨ R, et al: Depression–Executive Dysfunction Syndrome in stroke patients. Am J Geriatr Psychiatry 2005; 13:99–107 3. Bierman EJM, Comijs HC, Jonker C, et al: Effects of anxiety versus depression on cognition in later life. Am J Geriatr Psychiatry 2005; 13:686–693 4. Kiosses DN, Alexopoulos GS: IADL functions, cognitive deficits, and severity of depression: a preliminary study. Am J Geriatr Psychiatry 2005; 13:244–249 5. Mast BM: Impact of cognitive impairment on the phenomenology of geriatric depression. Am J Geriatr Psychiatry 2005; 13:694–700 6. Sachs-Ericsson N, Joiner T, Plant EA, et al: The influence of depression on cognitive decline in community-dwelling elderly persons. Am J Geriatr Psychiatry 2005; 13:402–408 7. Buckley TM, Schatzberg AF: Aging and the role of the HPA axis and rhythm in sleep and memory-consolidation. Am J Geriatr Psychiatry 2005; 13:344–352 8. De Ronchi D, Bellini F, Berardi D, et al: Cognitive status, depressive symptoms, and health status as predictors of functional disability among elderly persons with low-to-moderate education: the Faenza community aging study. Am J Geriatr Psychiatry 2005; 13:672–685 9. Rapp MA, Beeri MS, Schmeidler J, et al: Relationship of neuropsychological performance to functional status in nursing home residents and community-dwelling older adults. Am J Geriatr Psychiatry 2005; 13:450–459 10. Heinrichs RW: The primacy of cognition in schizophrenia. Am Psychol 2005; 60:229–242 11. Heaton RK, Paulsen J, McAdams LA, et al: Neuropsychological deficits in schizophrenia: Relationship to age, chronicity and dementia. Arch Gen Psychiatry 1994; 51:469–476 12. Heaton RK, Gladsjo JA, Palmer B, et al: The stability and course of neuropsychological deficits in schizophrenia. Arch Gen Psychiatry 2001; 58:24–32 13. Saykin AJ, Gur RC, Gur RE, et al: Neuropsychological function in schizophrenia. Selective impairment in memory and learning. Arch Gen Psychiatry 1991; 48:618–624 14. Austin MP, Mitchell P, Goodwin GM: Cognitive deficits in depression: possible implications for functional neuropathology. Br J Psychiatry 2001; 178:200–206
Am J Geriatr Psychiatry 14:5, May 2006
15. Bearden CE, Hoffman KM, Cannon TD: The neuropsychology and neuroanatomy of bipolar affective disorder: a critical review. Bipolar Disord 2001; 3:106–150 16. Miller WR: Psychological deficit in depression. Psychol Bull 1975; 82:238–260 17. Dickerson FB, Sommerville J, Origoni AE, et al: Outpatients with schizophrenia and bipolar I disorder: do they differ in their cognitive and social functioning? Psychiatry Res 2001; 102:21–27 18. Harvey PD, Powchik P, Parrella M, et al: Symptom severity and cognitive impairment in chronically hospitalised geriatric patients with affective disorders. Br J Psychiatry 1997; 170:369–374 19. Marvel CL, Paradiso S: Cognitive and neurological impairment in mood disorders. Psychiatr Clin North Am 2004; 27:19–36 20. Wolfe J, Granholm E, Butters N, et al: Verbal memory deficits associated with major affective disorders: a comparison of unipolar and bipolar patients. J Affect Disord 1987; 13:83–92 21. Van Gorp WG, Altshuler L, Theberge DC, et al: Cognitive impairment in euthymic bipolar patients with and without prior alcohol dependence. A preliminary study. Arch Gen Psychiatry 1998; 55:41–46 22. Green MF, Kern RS, Braff DL, et al: Neurocognitive deficits and functional outcome in schizophrenia: Are we measuring the “right stuff”? Schizophr Bull 2000; 26:119–136 23. Twamley EW, Doshi RR, Nayak GV, et al: Generalized cognitive impairments, ability to perform everyday tasks, and level of independence in community living situations of older patients with psychosis. Am J Psychiatry 2002; 159:2013–2020 24. Zarate CA, Tohen M, Land M, et al: Functional impairment and cognition in bipolar disorder. Psychiatr Q 2000; 71:309–329 25. Moore R, Blackwood N, Corcoran R, et al: Misunderstanding the intentions of others: An exploratory study of the cognitive aetiology of persecutory delusions in very late-onset schizophrenialike psychosis. Am J Geriatr Psychiatry 2006; 14:410–418 26. Tatsch MF, Bottino CMC, Azevedo D, et al: Neuropsychiatric symptoms in Alzheimer’s disease and cognitively impaired not demented elderly from a community-based sample in Brazil: Prevalence and relationship with dementia severity. Am J Geriatr Psychiatry 2006; 14:438–445 27. Brodaty H, Low L, Gibson L, et al: What is the best dementia screening instrument for general practitioners to use? Cognitive
389
Editorial screening in primary care. Am J Geriatr Psychiatry 2006; 14:391– 400 28. DeKosky ST, Orgogozo JM: Alzheimer disease: Diagnosis, costs, and dimensions of treatment. Alzheimer’s Disease and Associated Disorders 2001; 15:S3–S7 29. van Dyck CH, Schmitt FA, Olin JT. A responder analysis of memantine treatment in Alzheimer’s disease patients maintained on donepezil. Am J Geriatr Psychiatry 2006; 14:428–437 30. Tariot PN, Farlow MR, Grossberg GT, et al: Memantine treatment
390
in patients with moderate to severe Alzheimer disease already receiving donepezil: a randomized controlled trial. JAMA 2004; 291:317–324 31. Bhalla RK, Butters MA, Mulsant BH, et al: Persistence of neuropsychological deficits in the remitted state of late-life depression. Am J Geriatr Psychiatry. 2006; 14:419–427 32. Steffens DC, Snowden M, Fan M, et al: Cognitive impairment and depression outcomes in the IMPACT study. Am J Geriatr Psychiatry 2006; 14:401–409
Am J Geriatr Psychiatry 14:5, May 2006
The Importance of Cognition in the Conceptualization of both Dementia and Severe Mental Illness in Older People Elizabeth W. Twamley, Ph.D., Philip D. Harvey, Ph.D.
I
n the July/August 2004 issue of the American Journal of Geriatric Psychiatry, Dr. Barton Palmer’s introduction to the theme of Neuropsychology discussed the expanding role of neuropsychology in geriatric psychiatry.1 This issue’s theme is Cognition, which focuses less on the localization of cognitive impairment in the brain and more on the importance of cognition in understanding disease states. Cognitive impairment has long been understood as the hallmark of degenerative dementias such as Alzheimer disease, of course, but our understanding of the cognitive components of severe mental illness is still developing, as is our appreciation of the nature and strength of the linkage between cognition and the functional outcomes that are important to patients and their families. Psychiatric disorders, brain disorders that they are, are increasingly being conceptualized as having significant cognitive components. The empirical articles in the American Journal of Geriatric Psychiatry during 2005, for example, addressed cognition not only in Alzheimer disease, but also in stroke2 and anxiety and depression.3,4,5,6 The impact of cognition on function in both healthy elders and psychiatric populations also was highlighted.7,8,9 All of the severe mental illnesses appear to feature significant cognitive impairment along with psychiatric symptoms. Interestingly, these cognitive impairments are generally not a function of the other aspects of the illness, as striking as these features may be. Schizophrenia has increasingly been conceptualized as a cognitive disorder producing psychosis, rather than a psychotic disorder affecting cognition.10
The neuropsychological deficits of schizophrenia occur in multiple domains, including attention, working memory, learning, memory, processing speed, and executive functioning, and are relatively stable over time.11,12,13 The cognitive impairments seen in affective disorders, too, are increasingly being viewed as central to the illness, rather than mere epiphenomena.14 Bipolar disorder patients, even when in euthymic states, have cognitive deficits that are qualitatively and quantitatively similar to those seen in schizophrenia.15 Depression, too, has long been associated with cognitive dysfunction comparable to that seen in both bipolar disorder and schizophrenia.16 In one study of stable outpatients, schizophrenia and bipolar subjects did not differ on 9 of 10 neuropsychological tests administered17; in another study of chronically institutionalized patients, there were no overall differences between patients with schizophrenia, unipolar depression, and bipolar disorder on an 11-test cognitive assessment, while 18/30 PANSS items differed between the groups.18 As is the case in bipolar disorder and schizophrenia, the cognitive impairments of depression are seen even in stable outpatients.19 Both unipolar depressed and bipolar patients show deficits in verbal learning and memory consistent with an encoding deficit.14,20,21 The public health significance of cognitive functioning in older people cannot be understated. Better recognition of Alzheimer disease in its earliest state, for example, would have profound social and financial effects. Cognitive impairment also is a leading cause of disability in severe mental illness, often even
From the Department of Psychiatry, University of California, San Diego, San Diego, California (EWT); and the Department of Psychiatry, Mount Sinai School of Medicine, New York, New York (PDH). © 2006 American Association for Geriatric Psychiatry
Am J Geriatr Psychiatry 14:5, May 2006
387
Editorial more so than psychiatric symptoms.22,23,24 Further, functional recovery is much rarer than development of sustained symptomatic remission, with cognitive deficits predicting persistent functional disability. The articles in this special theme issue on Cognition are varied in their emphasis on basic versus clinical research and in their populations of study. The topics range from phenomenology to diagnosis, treatment, and prognosis. The uniting theme of Cognition, however, highlights the importance of understanding cognitive ability in order to fully understand both dementia and severe mental illness in older people. In the first article in this theme section, Moore and colleagues25 investigated the cognitive underpinnings of persecutory delusions in very late onset schizophrenia-like psychosis (SLP). Using both a probabilistic reasoning task and two tasks of social cognition, they found that patients with SLP differed from comparison subjects only on a task involving detection of deception by other people. They did not show deficits on the probabilistic reasoning task, assessing the tendency to jump to conclusions, or a pattern of externalizing blame for negative events (both common in younger schizophrenia patients). These findings illuminate the types of thinking errors that might lead to a fairly circumscribed symptom picture of persecutory delusions in SLP. Tatsch and colleagues26 investigated neuropsychiatric symptoms in a community-based sample of Brazilian elders with Alzheimer disease or Cognitive Impairment No Dementia (CIND). Both groups had significant levels of neuropsychiatric symptoms, including sleep disturbance, anxiety, and depression. However, over half of the Alzheimer disease group had significant apathy, whereas only 12% of the CIND group did. Furthermore, as cognitive impairment (as rated by the Clinical Dementia Rating scale) increased among the Alzheimer disease subjects, apathy became increasingly prominent. Thus, apathy and cognitive impairment may share a common substrate, perhaps frontal system impairment, in Alzheimer disease. The following article, by Brodaty and colleagues,27 concerns dementia screening in primary care. Early detection of Alzheimer disease, the most common cause of dementia, could result in earlier pharmacologic treatment and delayed nursing home placement, thus reducing the cost of Alzheimer disease care (currently estimated at $100 billion per year in
388
the US28). Additionally, early and accurate diagnoses aid patients and family members in health care decision-making. It makes sense that large-scale screening for Alzheimer disease will be necessary as the population grows older; such screening will most effectively take place in primary care settings. Brodaty and colleagues reviewed several brief, simple screening instruments that could be used by primary care physicians. Although they identified no perfect measure, they recommended the General Practitioner Assessment of Cognition (GPCOG), Mini-Cog, and Memory Impairment Screen (MIS) as being the three best. All three measures were comparable to the MMSE in terms of classification accuracy, but take less than five minutes to administer. Continuing the Alzheimer disease story, van Dyck and colleagues29 examined different definitions of treatment response in the context of a 24-week randomized controlled trial of memantine in moderateto-severe stage Alzheimer disease patients who were stabilized on donepezil. In this secondary analysis of the Tariot et al. trial,30 van Dyck and colleagues considered three definitions of treatment response: 1) cognitive improvement from baseline, 2) improvement or lack of decline in one of the primary outcomes (cognition, independence in activities of daily living, clinician’s impression of change, and neuropsychiatric symptoms), and 3) improvement or lack of decline in multiple primary outcomes. Compared to placebo, memantine treatment resulted in significantly higher response rates using the first two definitions of treatment response, and was statistically superior to placebo on six of the possible 10 combinations of multiple outcomes. The final two articles present complementary longitudinal investigations of cognitive impairment and late-life depression, and address important questions of prognosis in this population. Using comprehensive neuropsychological assessments, Bhalla and colleagues31 found that 30% of their unipolar depressed patients were cognitively impaired at baseline. Of this 30%, 94% continued to be cognitively impaired one year later, although their depression was remitted. Thus, cognition did not improve even with effective treatment of depression. They also found that among the 70% of patients who were cognitively intact at baseline, 23% were cognitively impaired at one-year follow-up, even though their depression was remitted. Thus, depression without cognitive
Am J Geriatr Psychiatry 14:5, May 2006
Twamley and Harvey impairment was a risk factor for future cognitive impairment one year later. In the final article of the Cognition section, Steffens and colleagues32 reported data from a large-scale, two-year, multisite trial addressing the question of cognition and treatment outcomes in late-life depression. Memory impairment, measured by three-item recall and three orientation questions, was present in 35% of the patients. Baseline memory impairment did not affect depression treatment outcomes, but memory decline during the two-year trial resulted in worse depression treatment outcomes. Both articles on cognitive impairment in late-life depression suggest that both conditions should be treated simulta-
neously in order to prevent further cognitive decline and to improve depression outcomes. The six articles comprising this special section on Cognition illustrate just a few of the ways in which cognition is relevant in geriatric psychiatry. The growing understanding of cognition as a “rate limiting step” in functional improvement with treatments of these illnesses makes imperative the further study of cognition not only in dementia, but also in other severe mental illnesses. Thus, further interdisciplinary research involving the fields of neuropsychology, cognitive neuroscience, and geriatric psychiatry will continue to illuminate diagnosis and treatment issues in geriatric psychiatry.
References 1. Palmer BW: The expanding role of neuropsychology in geriatric psychiatry. Am J Geriatr Psychiatry 2004; 12:338–341 2. Vataja R, Pohjasvaara T, Ma¨ntyla¨ R, et al: Depression–Executive Dysfunction Syndrome in stroke patients. Am J Geriatr Psychiatry 2005; 13:99–107 3. Bierman EJM, Comijs HC, Jonker C, et al: Effects of anxiety versus depression on cognition in later life. Am J Geriatr Psychiatry 2005; 13:686–693 4. Kiosses DN, Alexopoulos GS: IADL functions, cognitive deficits, and severity of depression: a preliminary study. Am J Geriatr Psychiatry 2005; 13:244–249 5. Mast BM: Impact of cognitive impairment on the phenomenology of geriatric depression. Am J Geriatr Psychiatry 2005; 13:694–700 6. Sachs-Ericsson N, Joiner T, Plant EA, et al: The influence of depression on cognitive decline in community-dwelling elderly persons. Am J Geriatr Psychiatry 2005; 13:402–408 7. Buckley TM, Schatzberg AF: Aging and the role of the HPA axis and rhythm in sleep and memory-consolidation. Am J Geriatr Psychiatry 2005; 13:344–352 8. De Ronchi D, Bellini F, Berardi D, et al: Cognitive status, depressive symptoms, and health status as predictors of functional disability among elderly persons with low-to-moderate education: the Faenza community aging study. Am J Geriatr Psychiatry 2005; 13:672–685 9. Rapp MA, Beeri MS, Schmeidler J, et al: Relationship of neuropsychological performance to functional status in nursing home residents and community-dwelling older adults. Am J Geriatr Psychiatry 2005; 13:450–459 10. Heinrichs RW: The primacy of cognition in schizophrenia. Am Psychol 2005; 60:229–242 11. Heaton RK, Paulsen J, McAdams LA, et al: Neuropsychological deficits in schizophrenia: Relationship to age, chronicity and dementia. Arch Gen Psychiatry 1994; 51:469–476 12. Heaton RK, Gladsjo JA, Palmer B, et al: The stability and course of neuropsychological deficits in schizophrenia. Arch Gen Psychiatry 2001; 58:24–32 13. Saykin AJ, Gur RC, Gur RE, et al: Neuropsychological function in schizophrenia. Selective impairment in memory and learning. Arch Gen Psychiatry 1991; 48:618–624 14. Austin MP, Mitchell P, Goodwin GM: Cognitive deficits in depression: possible implications for functional neuropathology. Br J Psychiatry 2001; 178:200–206
Am J Geriatr Psychiatry 14:5, May 2006
15. Bearden CE, Hoffman KM, Cannon TD: The neuropsychology and neuroanatomy of bipolar affective disorder: a critical review. Bipolar Disord 2001; 3:106–150 16. Miller WR: Psychological deficit in depression. Psychol Bull 1975; 82:238–260 17. Dickerson FB, Sommerville J, Origoni AE, et al: Outpatients with schizophrenia and bipolar I disorder: do they differ in their cognitive and social functioning? Psychiatry Res 2001; 102:21–27 18. Harvey PD, Powchik P, Parrella M, et al: Symptom severity and cognitive impairment in chronically hospitalised geriatric patients with affective disorders. Br J Psychiatry 1997; 170:369–374 19. Marvel CL, Paradiso S: Cognitive and neurological impairment in mood disorders. Psychiatr Clin North Am 2004; 27:19–36 20. Wolfe J, Granholm E, Butters N, et al: Verbal memory deficits associated with major affective disorders: a comparison of unipolar and bipolar patients. J Affect Disord 1987; 13:83–92 21. Van Gorp WG, Altshuler L, Theberge DC, et al: Cognitive impairment in euthymic bipolar patients with and without prior alcohol dependence. A preliminary study. Arch Gen Psychiatry 1998; 55:41–46 22. Green MF, Kern RS, Braff DL, et al: Neurocognitive deficits and functional outcome in schizophrenia: Are we measuring the “right stuff”? Schizophr Bull 2000; 26:119–136 23. Twamley EW, Doshi RR, Nayak GV, et al: Generalized cognitive impairments, ability to perform everyday tasks, and level of independence in community living situations of older patients with psychosis. Am J Psychiatry 2002; 159:2013–2020 24. Zarate CA, Tohen M, Land M, et al: Functional impairment and cognition in bipolar disorder. Psychiatr Q 2000; 71:309–329 25. Moore R, Blackwood N, Corcoran R, et al: Misunderstanding the intentions of others: An exploratory study of the cognitive aetiology of persecutory delusions in very late-onset schizophrenialike psychosis. Am J Geriatr Psychiatry 2006; 14:410–418 26. Tatsch MF, Bottino CMC, Azevedo D, et al: Neuropsychiatric symptoms in Alzheimer’s disease and cognitively impaired not demented elderly from a community-based sample in Brazil: Prevalence and relationship with dementia severity. Am J Geriatr Psychiatry 2006; 14:438–445 27. Brodaty H, Low L, Gibson L, et al: What is the best dementia screening instrument for general practitioners to use? Cognitive
389
Editorial screening in primary care. Am J Geriatr Psychiatry 2006; 14:391– 400 28. DeKosky ST, Orgogozo JM: Alzheimer disease: Diagnosis, costs, and dimensions of treatment. Alzheimer’s Disease and Associated Disorders 2001; 15:S3–S7 29. van Dyck CH, Schmitt FA, Olin JT. A responder analysis of memantine treatment in Alzheimer’s disease patients maintained on donepezil. Am J Geriatr Psychiatry 2006; 14:428–437 30. Tariot PN, Farlow MR, Grossberg GT, et al: Memantine treatment
390
in patients with moderate to severe Alzheimer disease already receiving donepezil: a randomized controlled trial. JAMA 2004; 291:317–324 31. Bhalla RK, Butters MA, Mulsant BH, et al: Persistence of neuropsychological deficits in the remitted state of late-life depression. Am J Geriatr Psychiatry. 2006; 14:419–427 32. Steffens DC, Snowden M, Fan M, et al: Cognitive impairment and depression outcomes in the IMPACT study. Am J Geriatr Psychiatry 2006; 14:401–409
Am J Geriatr Psychiatry 14:5, May 2006