Mood and motor trajectories in Parkinson's disease: multivariate latent growth curve modeling

Cross-Sectional and Longitudinal Association of Clinical and Neurocognitive Factors With Apathy in Patients With Parkinson Disease

BACKGROUND AND OBJECTIVES

A robust understanding of the natural history of apathy in Parkinson disease (PD) is foundational for developing effective clinical management tools. However, large longitudinal studies are lacking while the literature is inconsistent about even cross-sectional associations. We aimed to determine the longitudinal predictors of apathy development in a large cohort of people with PD and its cross-sectional associations and trajectories over time, using sophisticated Bayesian modeling techniques.

METHODS

People with PD followed up in the longitudinal New Zealand Parkinson's progression project were included. Apathy was defined using the neuropsychiatric inventory subscale ≥4, and analyses were also repeated using a less stringent cutoff of ≥1. Both MoCA and comprehensive neuropsychological testing were used as appropriate to the model. Depression was assessed using the hospital anxiety and depression scale. Cross-sectional Bayesian regressions were conducted, and a multistate predictive model was used to identify factors that predict the initial onset of apathy in nonapathetic PD, while also accounting for the competing risk of death. The relationship between apathy presence and mortality was also investigated.

RESULTS

Three hundred forty-six people with PD followed up for up to 14 years across a total of 1,392 sessions were included. Apathy occurrence did not vary significantly across the disease course (disease duration odds ratio [OR] = 0.55, [95% CI 0.28-1.12], affecting approximately 11% or 22% of people at any time depending on the NPI cutoff used. Its presence was associated with a significantly higher risk of death after controlling for all other factors (hazard ratio [HR] = 2.92 [1.50-5.66]). Lower cognition, higher depression levels, and greater motor severity predicted apathy development in those without motivational deficits (HR [cognition] = 0.66 [0.48-0.90], HR [depression] = 1.45 [1.04-2.02], HR [motor severity] = 1.37 [1.01-1.86]). Cognition and depression were also associated with apathy cross-sectionally, along with male sex and possibly lower dopaminergic therapy level, but apathy still occurred across the full spectrum of each variable (OR [cognition] = 0.58 [0.44-0.76], OR [depression] = 1.43 [1.04-1.97], OR [female sex] = 0.45 [0.22-0.92], and OR [levodopa equivalent dose] = 0.78 [0.59-1.04].

DISCUSSION

Apathy occurs across the PD time course and is associated with higher mortality. Depressive symptoms and cognitive impairment in particular predict its future development in those with normal motivation.

Motor dysfunction in Parkinson's patients: depression differences in a latent growth model

Objective

This study aims to utilize latent growth model (LGM) to explore the developmental trajectory of motor dysfunction in Parkinson's disease (PD) patients and investigate the relationship between depression and motor dysfunction.

Methods

Four-year follow-up data from 389 PD patients were collected through the Parkinson's Progression Marker Initiative (PPMI). Firstly, a univariate LGM was employed to examine the developmental trajectory of motor dysfunction in PD patients. Subsequently, depression levels were introduced as covariates into the model, and depression was further treated as a parallel growth latent variable to study the longitudinal relationship between motor dysfunction and depression.

Results

In the trajectory analysis of motor dysfunction, the fit indices for the quadratic growth LGM model were χ2 = 7.419, df = 6, CFI = 0.998, TLI = 0.997, SRMR = 0.019, and RMSEA = 0.025, indicating that the growth trend of motor dysfunction follows a quadratic curve rather than a simple linear pattern. Introducing depression symptoms as time-varying covariates to explore their effect on motor dysfunction revealed significant positive correlations (β = 0.383, p = 0.026; β = 0.675, p < 0.001; β = 0.385, p = 0.019; β = 0.415, p = 0.014; β = 0.614, p = 0.003), suggesting that as depression levels increase, motor dysfunction scores also increase. Treating depression as a parallel developmental process in the LGM, the regression coefficients for depression intercept on motor dysfunction intercept, depression slope on motor dysfunction slope, and depression quadratic factor on motor dysfunction quadratic factor were 0.448 (p = 0.046), 1.316 (p = 0.003), and 1.496 (p = 0.038), respectively. These significant regression coefficients indicate a complex relationship between depression and motor dysfunction, involving not only initial level associations but also growth trends over time and possible quadratic effects.

Conclusion

This study indicates a quadratic growth trajectory for motor dysfunction in PD, suggesting a continuous increase in severity with a gradual deceleration in growth rate. The relationship between depression and motor dysfunction is complex, involving initial associations, evolving trends over time, and potential quadratic effects. Exacerbation of depressive symptoms may coincide with motor function deterioration.

Apathy-like behaviour in tau mouse models of Alzheimer's disease and frontotemporal dementia

Apathy is the most common behavioural and psychological symptom in Alzheimer's disease (AD) and other neurodegenerative diseases including frontotemporal dementia (FTD) and Parkinson's disease (PD). In patients, apathy can include symptoms of loss of motivation, initiative, and interest, listlessness, and indifference, flattening of emotions, absence of drive and passion. Researchers have later refined this to a reduction in goal direct behaviours. In animals, specific symptoms of apathy-like behaviour have been modelled including goal directed or nest-building behaviour which are seen as indicative of proxies for motivation and daily activities. In the present study a nest-building protocol was established using four different inbred mouse strains (CD1, BALB/c, C57Bl/6J, C3H) before assessing AD and FTD tau transgenic mice of Line 1 (L1) and Line 66 (L66) in this paradigm. Female mice aged 5 - 6 months were assessed in the home cage over a period of 7 days with nest-building behaviour scored by three independent experimenters at intervals of 1-, 2- and 7-days post nestlet introduction. Inbred mouse strains displayed different levels of nesting behaviour. BALB/c mice were more proficient than CD1 and C3H mice, while all strains displayed similar nest-building behaviour by day 7. In the tau mouse models, L66 presented with impaired nesting compared to wild-type on days 1 and 2 (not day 7), whereas L1 performed like wild-type on all days. Anhedonia measured in a sucrose preference test was only observed in L66. Anhedonia and low nesting scores in L66 mice are indicative of apathy-like phenotypes. Differences evident between the L1 and L66 tau transgenic mouse models are likely due to the different human tau species expressed in these mice.

Future directions in psychiatric neurosurgery: Proceedings of the 2022 American Society for Stereotactic and Functional Neurosurgery meeting on surgical neuromodulation for psychiatric disorders

OBJECTIVE

Despite advances in the treatment of psychiatric diseases, currently available therapies do not provide sufficient and durable relief for as many as 30-40% of patients. Neuromodulation, including deep brain stimulation (DBS), has emerged as a potential therapy for persistent disabling disease, however it has not yet gained widespread adoption. In 2016, the American Society for Stereotactic and Functional Neurosurgery (ASSFN) convened a meeting with leaders in the field to discuss a roadmap for the path forward. A follow-up meeting in 2022 aimed to review the current state of the field and to identify critical barriers and milestones for progress.

DESIGN

The ASSFN convened a meeting on June 3, 2022 in Atlanta, Georgia and included leaders from the fields of neurology, neurosurgery, and psychiatry along with colleagues from industry, government, ethics, and law. The goal was to review the current state of the field, assess for advances or setbacks in the interim six years, and suggest a future path forward. The participants focused on five areas of interest: interdisciplinary engagement, regulatory pathways and trial design, disease biomarkers, ethics of psychiatric surgery, and resource allocation/prioritization. The proceedings are summarized here.

CONCLUSION

The field of surgical psychiatry has made significant progress since our last expert meeting. Although weakness and threats to the development of novel surgical therapies exist, the identified strengths and opportunities promise to move the field through methodically rigorous and biologically-based approaches. The experts agree that ethics, law, patient engagement, and multidisciplinary teams will be critical to any potential growth in this area.

The Profile and Evolution of Neuropsychiatric Symptoms in Multiple System Atrophy: Self- and Caregiver Report

OBJECTIVE

Recent research shows that patients with multiple system atrophy (MSA) have significant cognitive and neuropsychiatric comorbidities that can color the clinical presentation of the disease and affect their quality of life. The aims of this study were to determine the neuropsychiatric profile in a cohort of patients with the parkinsonian type of MSA (MSA-P) and their dynamic changes over a 1-year follow-up period and to compare rates of neuropsychiatric symptoms (NPSs) reported by caregivers and the patients themselves.

METHODS

Forty-seven patients were assessed at baseline; of these, 25 were assessed again after 1 year. NPS assessment tools included the Neuropsychiatric Inventory (NPI), the Beck Depression Inventory, the Hamilton Depression Rating Scale, the Hamilton Anxiety Rating Scale, and the Apathy Evaluation Scale.

RESULTS

The prevalence of NPSs in patients with MSA-P was very high, with depression, sleep disturbances, apathy, and anxiety being the most frequently occurring features. The evolution of NPSs was found to be independent of motor, autonomic, and cognitive symptoms. None of the scales measuring NPSs, including the NPI, were capable of detecting changes over the 1-year follow-up period. Although the overall prevalence of depression, apathy, and anxiety obtained from caregivers and the patients themselves was similar, reports from these two sources cannot be considered interchangeable.

CONCLUSIONS

The progression of neuropsychiatric symptoms was not a subject of rapid change in MSA-P, in contrast to the observed motor, autonomic, and cognitive deterioration. These findings suggest the need to investigate the utility of available instruments in capturing the evolution of NPSs in MSA over time.

Evolution of Apathy in Early Parkinson's Disease: A 4-Years Prospective Cohort Study

Objective: We investigated the prevalence, evolution, associated factors, and risk factors of apathy in a cohort of patients with early-stage Parkinson's disease (PD), who underwent a 4-years prospective follow-up. Methods: This study included 188 patients with PD (baseline disease duration <3 years) who underwent an annual evaluation using the Lille Apathy Rating Scale (LARS). Based on the cut-off value of -21 observed on the LARS, patients were categorized as PD with and without apathy. The generalized estimating equations (GEE) model was utilized to determine the factors associated with apathy, and the Cox proportional-hazards regression model was used to determine the predictors of apathy. Results: Apathy increased from a baseline rate of 18.6-28.8% after 4 years; notably, this rate was not persistent across patients' visits. The LARS score was independently associated with the male sex (B 8.131, p = 0.009), low Frontal Assessment Battery (FAB) scores (B 0.567, p = 0.011), low attention scores on the Montreal Cognitive Assessment (MOCA) test (B 0.217, p = 0.026), high Hamilton Depression Rating Scale (HDRS) scores (B 1.362, p < 0.001), high Unified Parkinson's Disease Rating Scale (UPDRS) part III scores (B 1.147, p < 0.001), and prolonged follow-up time (B 1.785, p = 0.048). A high HDRS score was the only predictor of apathy in PD [hazard ratio (HR) 1.043, p = 0.026]. Conclusions: The risk of apathy is higher in men with progressive PD accompanied by disease-specific motor and non-motor symptoms. Depression during early-stage PD is a primary risk factor for apathy in PD.

Targeting neurons in the gastrointestinal tract to treat Parkinson's disease

Background

Parkinson's disease (PD) is associated with α-synuclein (αS) aggregation within the enteric nervous system (ENS) and constipation. Squalamine displaces proteins that are electrostatically bound to intracellular membranes and through this mechanism suppresses aggregation of αS monomers into neurotoxic oligomers.

Objective

We sought to evaluate the safety of ENT-01 oral tablets (a synthetic squalamine salt), its pharmacokinetics, and its effect on bowel function in PD patients with constipation.

Methods

In Stage 1, 10 patients received escalating single doses from 25 to 200 mg/day or maximum tolerated dose (MTD). In Stage 2, 34 patients received daily doses escalating from 75 to a maximum of 250 mg/day, a dose that induced change in bowel function or MTD, followed by a fixed dose for 7 days, and a 2-week washout. Primary efficacy endpoint was defined as an increase of 1 complete spontaneous bowel movement (CSBM)/week, or 3 CSBM/week over the baseline period, as defined by FDA guidelines for prokinetic agents. Safety was also assessed.

Results

Over 80% of patients achieved the primary efficacy endpoint, with the mean number of CSBM/week increasing from 1.2 at baseline to 3.6 during fixed dosing (p = 1.2 × 10⁻⁷). Common adverse events included nausea in 21/44 (47%) and diarrhea in 18/44 (40%) patients. Systemic absorption was <0.3%.

Conclusions

Orally administered ENT-01 was safe and significantly improved bowel function in PD, suggesting that the ENS is not irreversibly damaged in PD. Minimal systemic absorption suggests that improvements result from local stimulation of the ENS. A double-blind, placebo-controlled study is now ongoing.

Inventory of real world data sources in Parkinson's disease

Background

Real world data have an important role to play in the evaluation of epidemiology and burden of disease; and in assisting health-care decision-makers, especially related to coverage and payment decisions. However, there is currently no overview of the existing longitudinal real world data sources in Parkinson’s disease (PD) in the USA. Such an assessment can be very helpful, to support a future effort to harmonize real world data collection and use the available resources in an optimal way.

Methods

The objective of this comprehensive literature review is to systematically identify and describe the longitudinal, real world data sources in PD in the USA, and to provide a summary of their measurements (categorized into 8 main dimensions: motor and neurological functions, cognition, psychiatry, activities of daily living, sleep, quality of life, autonomic symptoms and other). The literature search was performed using MEDLINE, EMBASE and internet key word search.

Results

Of the 53 data sources identified between May and August 2016, 16 were still ongoing. Current medications (81%) and comorbidities (79%) were frequently collected, in comparison to medical imaging (36%), genetic information (30%), caregiver burden (11%) and healthcare costs (2%). Many different measurements (n = 108) were performed and an interesting variability among used measurements was revealed.

Conclusions

Many longitudinal real world data sources on PD exist. Different types of measurements have been performed over time. To allow comparison and pooling of these multiple data sources, it will be essential to harmonize practices in terms of types of measurements.

Preliminary Evidence of Apathetic-Like Behavior in Aged Vesicular Monoamine Transporter 2 Deficient Mice

Apathy is considered to be a core feature of Parkinson’s disease (PD) and has been associated with a variety of states and symptoms of the disease, such as increased severity of motor symptoms, impaired cognition, executive dysfunction and dementia. Apart from the high prevalence of apathy in PD, which is estimated to be about 40%, the underlying pathophysiology remains poorly understood and current treatment approaches are unspecific and proved to be only partially effective. In animal models, apathy has been sub-optimally modeled, mostly by means of pharmacological and stress-induced methods, whereby concomitant depressive-like symptoms could not be ruled out. In the context of PD only a few studies on toxin-based models (i.e., 6-hydroxydopamine (6-OHDA) or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)) claimed to have determined apathetic symptoms in animals. The assessment of apathetic symptoms in more elaborated and multifaceted genetic animal models of PD could help to understand the pathophysiological development of apathy in PD and eventually advance specific treatments for afflicted patients. Here we report the presence of behavioral signs of apathy in 12 months old mice that express only ~5% of the vesicular monoamine transporter 2 (VMAT2). Apathetic-like behavior in VMAT2 deficient (LO) mice was evidenced by impaired burrowing and nest building skills, and a reduced preference for sweet solution in the saccharin preference test, while the performance in the forced swimming test was normal. Our preliminary results suggest that VMAT2 deficient mice show an apathetic-like phenotype that might be independent of depressive-like symptoms. Therefore VMAT2 LO mice could be a useful tool to study the pathophysiological substrates of apathy and to test novel treatment strategies for apathy in the context of PD.

Mood Differences Among Parkinson's Disease Patients With Mild Cognitive Impairment

Studies with healthy elderly adults suggest that apathy, depression, and anxiety are more common among individuals with mild cognitive impairment (MCI). This study examined differences in mood/amotivational symptoms among patients with Parkinson's disease (PD) with and without MCI. Patients with PD (N=214) underwent neurocognitive evaluations including assessment of apathy (Apathy Scale), depression (Beck Depression Inventory-II), and trait anxiety (State-Trait Anxiety Inventory trait scale). Trait anxiety and depression were more severe in patients with PD with MCI. Delineation of MCI into amnestic and nonamnestic subtypes revealed greater depression, apathy, and anxiety among patients with PD with amnestic MCI relative to cognitively intact patients with PD. Patients with PD and MCI report greater mood symptoms compared to patients with PD who are cognitively intact.

Baseline predictors of worsening apathy in Parkinson's disease: A prospective longitudinal study

INTRODUCTION

Apathy is one of the most common behavioural disorders in Parkinson's disease (PD) and contributes significantly to a reduced quality of life in PD patients.

METHODS

We conducted a prospective longitudinal study of 89 mild PD patients over 18 months, measuring apathy symptoms at 6-monthly intervals using the Starkstein Apathy Scale, as well as measures of motor and non-motor symptoms, cognitive function, and functional disability at baseline. Mixed-effects models were used to characterise the individual trajectories of apathy symptom severity, and linear regression with stepwise elimination procedure was used to select significant baseline predictors.

RESULTS

Clinically significant levels of apathy were present in 42.7% of our sample at baseline, with symptom severity remaining relatively stable on average over the course of 18 months. Male gender, lower educational attainment, higher depression symptom severity, more severe functional disability, and the presence of dyskinesias at study entry predicted increasing apathy over the subsequent 18 months.

CONCLUSIONS

Patients with these factors are at risk for progression of apathy, which may be prevented by treating depression and functional disability. Further studies are needed to address both the specific neurobiological pathways and psychosocial factors underpinning apathy in PD.

Depression and anxiety are co-morbid but dissociable in mild Parkinson's disease: A prospective longitudinal study of patterns and predictors

BACKGROUND

Depression and anxiety are common in Parkinson's disease (PD) and contribute significantly to a reduced quality of life in PD patients. Though they often co-exist, it is unclear whether depression and anxiety result from a shared pathological process. We studied the longitudinal course and determinants of depression and anxiety in PD in order to understand which factors contribute to the development of these symptoms.

METHODS

We conducted a prospective longitudinal study of 89 mild PD patients over 18 months, measuring depressive and anxiety symptoms at 6 monthly intervals using the Geriatric Depression Scale and Hospital Anxiety and Depression Scale--'Anxiety' subscale. Univariate and multivariate Generalised Estimating Equations were used to investigate the course of depression and anxiety and their association with demographic factors, motor measures, non-motor symptoms, and pharmacological factors.

RESULTS

Depression and anxiety were co-morbid in 13.5% of the sample. Depressive symptoms remained relatively stable while anxiety symptoms improved over the course of 18 months. Severity of depressive symptoms was associated with female gender, motor fluctuations, apathy, and anxiety, while severity of anxiety was associated with older age, higher educational attainment, shorter disease duration, younger age of disease onset, and excessive daytime sleepiness.

CONCLUSIONS

Although depression and anxiety are frequently co-morbid in PD, they were dissociable from each other. They had distinct trajectories and different longitudinal relationships with demographic, motor, and non-motor factors that were unique to each disorder.

Motivational engagement in Parkinson's disease: Preparation for motivated action

The current study investigated whether motivational dysfunction in Parkinson's patients is related to a deficit in preparing for motivated behavior. Based on previous studies, it was hypothesized that PD patients would show reduced preparation for action specifically when faced with threat (of loss) and that reduced action preparation would relate to self-report of apathy symptoms. The study measured an electrocortical correlate of preparation for action (CNV amplitude) in PD patients and healthy controls, as well as defensive and appetitive activation during emotional perception (LPP amplitude). The sample included 18 non-demented PD patients (tested on dopaminergic medications) and 15 healthy controls who responded as quickly as possible to cues signaling threat of loss or reward, in which the speed of the response determined the outcome. Results indicated that, whereas PD patients showed similar enhanced action preparation with the addition of incentives to controls, PD patients showed generally reduced action preparation, evidenced by reduced CNV amplitude overall. Results suggest that PD patients may have behavioral issues due to globally impaired action preparation but that this deficit is not emotion-specific, and movement preparation may be aided by incentive in PD patients.

Longitudinal relationships between Alzheimer disease progression and psychosis, depressed mood, and agitation/aggression

OBJECTIVES

Behavioral and psychological symptoms of dementia (BPSD) are prevalent in Alzheimer disease (AD) and are related to poor outcomes such as nursing home placement. No study has examined the impact of individual BPSD on dependence, a clinically important feature that reflects changing patient needs and their effect on caregivers. The current study characterized independent cross-sectional and longitudinal relationships between three BPSD (psychosis, depressed mood, and agitation/aggression), cognition, and dependence to better understand the interplay between these symptoms over time.

DESIGN

The Predictors Study measured changes in BPSD, cognition, and dependence every 6 months in patients with AD. Cross-sectional and longitudinal relationships between individual BPSD, cognition, and dependence over 6 years were characterized by using multivariate latent growth curve modeling. This approach characterizes independent changes in multiple outcome measures over time.

SETTING

Four memory clinics in the United States and Europe.

PARTICIPANTS

A total of 517 patients with probable AD.

MEASUREMENTS

Columbia University Scale for Psychopathology, modified Mini-Mental State Examination, and Dependence Scale.

RESULTS

Both psychosis and depressed mood at study entry were associated with worse subsequent cognitive decline. Independent of cognitive decline, initial psychosis was associated with worse subsequent increases in dependence. Rates of increase in agitation/aggression separately correlated with rates of declines in both cognition and independence.

CONCLUSIONS

Although purely observational, our findings support the poor prognosis associated with psychosis and depression in AD. Results also show that agitation/aggression tracks declines in cognition and independence independently over time. Targeted intervention for individual BPSD, particularly psychosis, could have broad effects not only on patient well-being but also on care costs and family burden.

Latent growth-curve analysis reveals that worsening Parkinson's disease quality of life is driven by depression

OBJECTIVE

Parkinson's disease (PD) is a neurodegenerative disorder resulting in a wide variety of symptoms. The current study examined the influence of apathy, depression and motor symptoms on quality of life (QoL) in PD patients. Information was drawn from an 18-month period.

METHOD

Participants (N = 397) were assessed for apathy (Apathy Scale; Starkstein et al., 1992), depression (Beck Depression Inventory-II; Beck, Steer, Ball & Ranieri, 1996), motor severity (Unified Parkinson's Disease Rating Scale, Part III; UPDRS; Fahn, Elton & Committee, 1987), and QoL (Parkinson's Disease Questionnaire-39; Jenkinson, Fitzpatrick, Peto, Greenhall, & Hyman,1997) at 3 time points: an initial clinical evaluation (baseline), a 6-month follow-up, and an 18-month follow-up. Latent growth-curve models were used to determine the influence of apathy, depression, and motor symptoms on QoL trajectories.

RESULTS

Greater difficulties with QoL at baseline showed the strongest relationship to more severe depression symptoms, followed by more severe motor symptoms, younger age, and less education (all p values < .001). Worsening of QoL over the 18-month period was only predicted by a worsening of depression (p = .003). The relationship between QoL and depression symptoms remained significant in a subsample of nondepressed PD patients.

CONCLUSION

Overall, findings from the current study suggest that self-reported QoL among PD patients is primarily related to depression. Future efforts to improving clinical care of PD patients may benefit by focusing on improving psychosocial adjustment or treatments targeting depression.

Social cognition in Alzheimer's disease: a separate construct contributing to dependence

The extent to which social cognitive changes reflect a discrete constellation of symptoms dissociable from general cognitive changes in Alzheimer's disease (AD) is unclear. Moreover, whether social cognitive symptoms contribute to disease severity and progression is unknown. The current multicenter study investigated cross-sectional and longitudinal associations between social cognition measured with six items from the Blessed Dementia Rating Scale, general cognition, and dependence in 517 participants with probable AD. Participants were monitored every 6 months for 5.5 years. Results from multivariate latent growth curve models adjusted for sex, age, education, depression, and recruitment site revealed that social cognition and general cognition were unrelated cross-sectionally and throughout time. However, baseline levels of each were related independently to dependence, and change values of each were related independently to change in dependence. These findings highlight the separability of social and general cognition in AD. Results underscore the relevance of considering social cognition when modeling disease and estimating clinical outcomes related to patient disability.

Apathy correlates with cognitive performance, functional disability, and HIV RNA plasma levels in HIV-positive individuals

We examined the relationship of apathy with neurocognitive performance, age, disease markers, and functional disability in 116 HIV-infected individuals. Apathy was assessed with the Apathy Evaluation Scale and was significantly associated with highest HIV plasma level, functional disability, and neurocognitive performance. Individuals with higher apathy levels demonstrated a stronger association between age and processing speed performance. Our findings suggest that apathy is related to poor neuropsychological functioning, HIV plasma levels, and increased functional disability in individuals with HIV. Additionally, to our knowledge, this is the first study to demonstrate an interactive effect of age and apathy on neuropsychological performance in HIV.

Coupled cognitive and functional change in Alzheimer's disease and the influence of depressive symptoms

In Alzheimer's disease (AD), cognition and function are only moderately correlated in cross-sectional studies, and studies of their longitudinal association are less common. One potential non-cognitive contributor to function is depression, which has been associated with poorer clinical outcomes. The current study investigated longitudinal associations between functional abilities, cognitive status, and depressive symptoms in AD. 517 patients diagnosed with probable AD and enrolled in The Multicenter Study of Predictors of Disease Course in Alzheimer's Disease were included. Patients were followed at 6-month intervals over 5.5 years. Longitudinal changes in the Blessed Dementia Rating Scale, modified Mini-Mental State Exam, and the depression subscale of the Columbia University Scale for Psychopathology in AD were examined in a multivariate latent growth curve model that controlled for gender, age, education, and recruitment site. Results showed that cognition and function worsened over the study period, whereas depressive symptoms were largely stable. Rates of change in cognition and function were correlated across participants and coupled within participants, indicating that they travel together over time. Worse initial cognitive status was associated with faster subsequent functional decline, and vice versa. Higher level of depressive symptoms was associated with worse initial functioning and faster subsequent cognitive and functional decline. These findings highlight the importance of both cognitive and psychiatric assessment for functional prognosis. Targeting both cognitive and depressive symptoms in the clinical treatment of AD may have incremental benefit on functional abilities.