dementia causes a high burden of suffering for patients and their families ( boustani et al 2003a ) . for patients , in addition to cognitive and functional deterioration , dementia leads to behavioral and psychological complications , increased use of health and social services , complicated clinical management of other comorbid conditions , and increased risk for medical complications such as delirium , falls , motor vehicle crashes , incontinence , fractures , and infections . for family caregivers , dementia can lead to higher levels of anxiety , depression , use of psychotropic medications , sleep problems , and chronic fatigue ( boustani et al 2003a ) ( see table 1 ) . in 2003 , dementia constituted 11% of total years lived with disability in people aged 60 years and older . this is more than cancer , stroke or cardiovascular disease ( ferris et al 2005 ) . currently , medicare recipients with dementia account for 34% of medicare spending , even though they constitute only 13% of the total medicare beneficiaries . by 2050 , medicare will be spending over $ 1 trillion on beneficiaries with this syndrome ( the lewin group , 2004 ) . the majority of patients with dementia receive their care within a primary care system ( boustani et al 2005 ; callahan et al 2006 ) . in this health care setting , dementia prevalence is 2% among patients aged 65 to 69 years , 7% among those aged 70 to 79 years , and 17% among older adults aged 80 and older ( boustani et al 2005 ) . research studies found that less than a third of these patients are recognized by the primary care system as having dementia ( boustani et al 2003a , 2005 ) . patients with dementia suffer from numerous chronic medical conditions , receive multiple prescriptions including psychotropic drugs , display a wide range of behavioral and psychological symptoms , and extensively utilize the health care system ( boustani et al 2003a ; callahan et al 2006 ; schubert et al 2006 ) ( see table 2 ) . more than 20% of these patients with dementia are exposed to at least one definite anticholinergic medication and less than 10% are prescribed cholinesterase inhibitors ( schubert et al 2006 ) . unfortunately , the complicated medical and psychiatric needs of demented patients affect not only their own care but also the health of their informal caregivers ( guerriero austrom et al 2004 ; callahan et al 2006 ; schubert et al 2006 ) . thus , enhancing the primary care of patients with dementia will require additional financial , educational and social resources ( boustani et al 2005 ; callahan et al 2006 ) . dementia is characterized by a complex interaction of cognitive , functional , behavioral and psychological symptoms that decrease the quality of life for both the patient and the caregiver . the scope of such integrated management must include pharmacological therapies and psychosocial interventions that target the entire spectrum of dementia symptomatology . an efficacious management would most likely stabilize or slow the cognitive decline ; stabilize or prevent additional functional disability ; and decrease the severity or delay the emergence of behavioral and psychological symptoms of dementia ( bpsd ) ( see table 3 ) . to date , the united states federal drug agency ( fda ) and the european union drug evaluation agency have approved two classes of medications for the treatment of ad , cholinesterase inhibitors ( cheis ) ( donepezil , rivastigmine , galantamine ) and a nmda receptor antagonist ( memantine ) . recently , the two agencies approved the use of rivastigmine , a chei , for patients with parkinson disease dementia . cheis are generally considered the first line treatment , especially in mild dementia . in comparison to placebo , 6-month therapy with a chei has demonstrated statistically significant positive effects on cognition ( boustani , m et al 2003a ; 2003b ) . the level of improvement shown was approximately equivalent to a 5- to 10-month delay in the progression of the disease . memantine is approved for the treatment of patients with moderate to severe ad ( mini mental status examination < 18 ) . in comparison to placebo , memantine produces a similar effect to cheis on patients cognition with a mean difference of 4 points on the severe impairment battery ( sib ) ( sib range is 0 to 100 points ) ( areosa sastre a et al 2006 ) . moreover , memantine has also been evaluated as an add - on ( combined ) therapy to cheis among patients with moderate to severe dementia and has led to a significant cognitive difference of 3 points on the sib ( areosa sastre et al 2006 ) . treatment with cheis and memantine may , however , lead to adverse effects such as nausea , vomiting , and diarrhea for cheis and headache , confusion and constipation for memantine ( boustani m et al 2003a , 2003b ; areosa sastre a et al 2006 ) . since there is a lack of universally accepted measures to evaluate the impact of cheis and memantine on the functional performance of patients with ad and other dementias , it is difficult to appreciate the day to day impact of these medications on functional disability . in general , the effect of chei and memantine on daily function appears minimal ( boustani et al 2003a , 2003b ; livingston and katona 2004 ; areosa sastre et al 2006 ) . however , using time to functional decline as an outcome measure and in comparison to placebo , donepezil demonstrated a 5-month delay in such a decline ( boustani et al 2003a , 2003b ) . furthermore , 34% of patients with moderate to severe ad did not decline functionally after 6 months of treatment with memantine versus 20% of those receiving placebo ( livingston and katona 2004 ) . the non - cognitive behavioral and psychological symptoms in dementia ( bpsd ) can be defined as verbal , vocal , or motor behavior that is inappropriate for the setting , and reflects inadequate ability to cope with internal and/or environmental stressors . more than 90% of patients with dementia will experience bpsd at some point during the course of their illness ( finkel et al 2000 ) . aggression is the most serious symptom and seems to be present in 30% of patients with dementia attending primary care clinics ( haupt et al 2000 ) . the current management of aggression is , at best , moderately successful , even in controlled trials . one reason for the limited effectiveness of aggression management is the current focus on pharmacologic interventions used in the setting of an acute crisis . the traditional pharmacological management of bpsd in general and aggression in particular includes the use of typical and atypical neuroleptics , antidepressants , anticonvulsants , hypnotics , and cheis . however , these pharmacologic interventions have not been approved by the fda for such therapy , their efficacy is limited , and they produce numerous side effects ( schneider et al 2005 ; sink et al 2005 ; schneider et al 2006 ) . neuroleptics in particular can lead to the development of extra - pyramidal signs , gait abnormalities , sedation , increased incidence of cerebrovascular events , and higher mortality rates ( schneider et al 2005 , 2006 ; sink et al 2005 ) . to date , the united states federal drug agency ( fda ) and the european union drug evaluation agency have approved two classes of medications for the treatment of ad , cholinesterase inhibitors ( cheis ) ( donepezil , rivastigmine , galantamine ) and a nmda receptor antagonist ( memantine ) . recently , the two agencies approved the use of rivastigmine , a chei , for patients with parkinson disease dementia . cheis are generally considered the first line treatment , especially in mild dementia . in comparison to placebo , 6-month therapy with a chei has demonstrated statistically significant positive effects on cognition ( boustani , m et al 2003a ; 2003b ) . the level of improvement shown was approximately equivalent to a 5- to 10-month delay in the progression of the disease . memantine is approved for the treatment of patients with moderate to severe ad ( mini mental status examination < 18 ) . in comparison to placebo , memantine produces a similar effect to cheis on patients cognition with a mean difference of 4 points on the severe impairment battery ( sib ) ( sib range is 0 to 100 points ) ( areosa sastre a et al 2006 ) . moreover , memantine has also been evaluated as an add - on ( combined ) therapy to cheis among patients with moderate to severe dementia and has led to a significant cognitive difference of 3 points on the sib ( areosa sastre et al 2006 ) . treatment with cheis and memantine may , however , lead to adverse effects such as nausea , vomiting , and diarrhea for cheis and headache , confusion and constipation for memantine ( boustani m et al 2003a , 2003b ; areosa sastre a et al 2006 ) . since there is a lack of universally accepted measures to evaluate the impact of cheis and memantine on the functional performance of patients with ad and other dementias , it is difficult to appreciate the day to day impact of these medications on functional disability . in general , the effect of chei and memantine on daily function appears minimal ( boustani et al 2003a , 2003b ; livingston and katona 2004 ; areosa sastre et al 2006 ) . however , using time to functional decline as an outcome measure and in comparison to placebo , donepezil demonstrated a 5-month delay in such a decline ( boustani et al 2003a , 2003b ) . furthermore , 34% of patients with moderate to severe ad did not decline functionally after 6 months of treatment with memantine versus 20% of those receiving placebo ( livingston and katona 2004 ) . the non - cognitive behavioral and psychological symptoms in dementia ( bpsd ) can be defined as verbal , vocal , or motor behavior that is inappropriate for the setting , and reflects inadequate ability to cope with internal and/or environmental stressors . more than 90% of patients with dementia will experience bpsd at some point during the course of their illness ( finkel et al 2000 ) . aggression is the most serious symptom and seems to be present in 30% of patients with dementia attending primary care clinics ( haupt et al 2000 ) . the current management of aggression is , at best , moderately successful , even in controlled trials . one reason for the limited effectiveness of aggression management is the current focus on pharmacologic interventions used in the setting of an acute crisis . the traditional pharmacological management of bpsd in general and aggression in particular includes the use of typical and atypical neuroleptics , antidepressants , anticonvulsants , hypnotics , and cheis . however , these pharmacologic interventions have not been approved by the fda for such therapy , their efficacy is limited , and they produce numerous side effects ( schneider et al 2005 ; sink et al 2005 ; schneider et al 2006 ) . neuroleptics in particular can lead to the development of extra - pyramidal signs , gait abnormalities , sedation , increased incidence of cerebrovascular events , and higher mortality rates ( schneider et al 2005 , 2006 ; sink et al 2005 ) . complex adaptive system ( cas ) is an open , dynamic and flexible network that is considered complex due to its composition of numerous interconnected , semi - autonomous , competing and collaborating members ( mcdaniel et al 2003 ; stoebel et al 2005 ) . the members of cas can be individuals , teams , functional groups , social institutions , or organizational processes . the cas is considered adaptive due to its capability of learning from its previous experiences and its flexibility to accommodate change in the connecting pattern of its members ( mcdaniel et al 2003 ; stoebel et al 2005 ) . cas is characterized ( see table 4 ) by emergent behaviors as opposed to predetermined ones and self - organized control instead of hierarchical pyramid - based central control ( mcdaniel et al 2003 ; stoebel et al 2005 ) . health care delivery organizations such as primary care clinics are an example of cas ( stroebel et al 2005 ) . these clinics usually include administrative assistants , clinic managers , nursing staff , clinical providers , billing specialists and other individuals who each bring their own perspectives , skills , experiences , and goals to patient care . these clinic members interact constantly in a nonlinear way and are continually faced with external and internal changes , such as patient s medical status , insurance requirements , regulations , new research findings , member turnover and legal issues . primary care clinics have been described as complex adaptive systems with local critical nonlinear relationships that produce unpredictable behavioral patterns or dynamics ( mcdaniel et al 2003 ; stoebel et al 2005 ) . any attempt to rigidly control this cas may increase problems by paralyzing the members ability to learn and take action to affect outcomes ( mcdaniel et al 2003 ; stoebel et al 2005 ) . although the current system of primary care does not have the resources to provide the appropriate diagnosis , evaluation , education , and complex management required for patients with dementia ( gueerriero austrom et al 2004 ; boustani et al 2005 ; callahan et al 2006 ; schubert et al 2006 ) , understanding primary care clinics as a cas may enhance our capacity to develop a flexible process of minimally standardized approaches to assess and manage patients with dementia . such a process would have the best probability of surviving the unknowable future challenges that will face these primary care clinics . over the past decade , indiana university center for aging research used the lens of cas to develop such a collaborative and minimally standardized approach to assess and manage patients with dementia within a primary care system called prevent - memory loss ( boustani et al 2005 ; callahan et al 2006 ; guerriero austrom et al 2004 ) . the efficacy of prevent program was evaluated in a randomized controlled trial that enrolled 153 older adults with alzheimer disease and included their caregivers ( callahan et al 2006 ) . the prevent program included the following minimally specified components : ( 1 ) dementia care manager ( dcm ) ; ( 2 ) electronic tracking of patients status ; ( 3 ) interdisciplinary dementia management resources ; ( 4 ) collaborative work with the patients primary care provider ; and ( 5 ) caregiver support ( see figure 1 ) . the patients were enrolled in prevent via a screening and diagnosis program for all patients aged 65 and older presenting to their primary care physician with or without dementia related symptoms . the dcm provided each dyad of patient and caregiver with educational material related to the nature of alzheimer disease and community resources . this dcm trained the patient s caregiver in problem solving skills related to patients functional disability and behavioral and psychological symptoms ; the dcm was also available to the caregivers over the phone or for face - to - face visits at the primary care clinic or the patient s home for any dementia related crisis , such as aggressive behaviors and caregiver burden . moreover , the dcm coordinated a monthly care - giver support meeting that included an exercise program for the patients . in addition to consideration for enhancing the patient s cholinergic system via stopping any definite anticholinergic medication and initiating treatment with cholinesterase inhibitors , the prevent interdisciplinary resource team developed standard pharmacological and non - pharmacological protocols to identify , monitor , and treat behavioral and psychological symptoms of dementia ( guerriero austrom et al 2004 ) . in comparison to patients randomized to the usual care , prevent patients had significantly fewer bpsd ( 43% vs 71% with p < 0.05 ) ( callahan et al 2006 ) . such improvement in bpsd was not related to higher use of neuroleptics ( 13% vs 7% , p = 0.3 ) or sedatives ( 10% vs 9.5% , p = 1.0 ) . however , prevent patients were more likely to receive cheis ( 80% vs 55% , p < 0.01 ) and antidepressants ( 45% vs 28% , p < 0.05 ) . despite its impact on bpsd and caregiver stress , prevent program did not affect the patients cognition , activities of daily living , or rates of hospitalization , nursing home placement or death . the management of patients with dementia in primary care is a challenge to our current health care delivery . redesigning our health care system using the lens of cas to accommodate a program such as prevent would address this challenge . healthcare delivery programs such as prevent enhance the current primary care system by integrating a dementia recognition process within a dementia management system . to succeed , this program must be coordinated by a clinician liaison trained in dementia management and supported with access to community resources and interdisciplinary specialists in dementia care , such as geriatricians , geriatric psychiatrists , geriatric neurologists and geriatric psychologists .