Updating Apathy: Using Research Domain Criteria to Inform Clinical Assessment and Diagnosis of Disorders of Motivation

A transdiagnostic review of neuroimaging studies of apathy and disinhibition in dementia

Apathy and disinhibition are common and highly distressing neuropsychiatric symptoms associated with negative outcomes in persons with dementia. This paper is a critical review of functional and structural neuroimaging studies of these symptoms transdiagnostically in dementia of the Alzheimer type, which is characterized by prominent amnesia early in the disease course, and behavioural variant frontotemporal dementia, characterized by early social-comportmental deficits. We describe the prevalence and clinical correlates of these symptoms and describe methodological issues, including difficulties with symptom definition and different measurement instruments. We highlight the heterogeneity of findings, noting however, a striking similarity of the set of brain regions implicated across clinical diagnoses and symptoms. These regions involve several key nodes of the salience network, and we describe the functions and anatomical connectivity of these brain areas, as well as present a new theoretical account of disinhibition in dementia. Future avenues for research are discussed, including the importance of transdiagnostic studies, measuring subdomains of apathy and disinhibition, and examining different units of analysis for deepening our understanding of the networks and mechanisms underlying these extremely distressing symptoms.

Revisiting Apathy in Alzheimer's Disease: From Conceptualization to Therapeutic Approaches

Apathy is a neurobehavioral syndrome characterized by impaired motivation for goal-directed behaviors and cognitive activity, alongside blunted affect. Apathy is a common neuropsychiatric syndrome in Alzheimer's disease (AD), with a 5-year prevalence over 70%. Apathy also serves as a prognostic indicator, correlating with the progression of AD. Despite advances in its conceptualization and understanding of its neural basis, there is very limited empirical evidence to support the available strategies for the treatment of apathy in AD. Given its complex pathophysiology, including distinct substrates for different apathy dimensions (affective, cognitive, and behavioral), it is unlikely that a single pharmacological or nonpharmacological strategy will be effective for all cases of apathy in AD. High-quality evidence research is needed to better understand the role of specific strategies aiming at a personalized approach.

Diagnostic criteria for apathy in neurocognitive disorders

INTRODUCTION

Apathy is common in neurocognitive disorders (NCD) but NCD-specific diagnostic criteria are needed.

METHODS

The International Society for CNS Clinical Trials Methodology Apathy Work Group convened an expert group and sought input from academia, health-care, industry, and regulatory bodies. A modified Delphi methodology was followed, and included an extensive literature review, two surveys, and two meetings at international conferences, culminating in a consensus meeting in 2019.

RESULTS

The final criteria reached consensus with more than 80% agreement on all parts and included: limited to people with NCD; symptoms persistent or frequently recurrent over at least 4 weeks, a change from the patient's usual behavior, and including one of the following: diminished initiative, diminished interest, or diminished emotional expression/responsiveness; causing significant functional impairment and not exclusively explained by other etiologies.

DISCUSSION

These criteria provide a framework for defining apathy as a unique clinical construct in NCD for diagnosis and further research.

Apathy and neurocognitive correlates: review from the perspective of 'precision psychiatry'

PURPOSE OF REVIEW

From the perspective of motivated behaviour and the so-called 'precision psychiatry', we try to identify recent advances in the neurocognitive and biological correlates of apathy.

RECENT FINDINGS

New evidence supports the notion that apathy is a common transdiagnostic and heterogeneous clinical syndrome, now conceptualized as a reduction in 'goal-directed' activity. Similarly, abundant evidence has been found related to neurocognitive correlates of apathy and the associations between clinical apathy and the processes primarily responsible for mediating motivational drive and effort-based decision making.Notwithstanding that the neurobiological basis is still poorly understood, there is some agreement in recent articles about a common system-level mechanism underlying apathy, pointing at specific medial frontal cortex and subcortical structures, including anterior cingulate cortex, medial orbitofrontal cortex and ventral striatum and related circuitry.

SUMMARY

Although difficulties in interpreting the results of these studies are apparent, because of different concepts of apathy used and methodological shortcomings identified, we have found consistent advances in the neurocognitive and biological correlates of apathy, relevant for the deep phenotyping proposed by the 'precision psychiatry' approach. This framework may eventually facilitate the identification of predictive-risk models and new specific therapeutic targets in psychiatry.

The emotional disorders associated with multiple sclerosis

Multiple sclerosis (MS) is associated with a high prevalence of emotional and mood disorders. Emotional disorders may worsen during illness progression and affect the quality of life of patients and their families. MS is often associated with depression, with an increased risk of suicide, poor adherence to treatment, decreased functional status, and quality of life. The diagnosis and treatment of emotional and mood disorders in these patients is often challenging since several symptoms of these disorders overlap with those of MS. Other prevalent emotional disorders in MS include bipolar disorder, anxiety disorders, emotional blunting (apathy), and pseudobulbar affect. Early recognition and treatment of these comorbidities could contribute to the reduction of disability and even to decreased mortality. The aim of this chapter is to provide an up-to-date review of mood and emotional disorders that are often associated with MS, focusing on their epidemiology, clinical features, pathogenesis, assessment, and treatment. The interplay between the psychosocial impact of the chronic disability and the demyelinating structural lesions of the brain in precipitating emotional and mood disorders is discussed, as well as its implications for diagnosis and treatment.

A central role for apathy in the effectiveness of interventions for cancer-related fatigue

OBJECTIVE

Cancer-related fatigue (CRF) affects a substantial number of cancer patients and survivors. Recommendations for CRF treatments are largely based on results of randomized controlled trials. The interpretability of such results is limited to patients eligible and willing to participate in these trials. We aimed to address this limitation in a retrospective study of patients seen at a CRF clinic in a comprehensive cancer center. The objectives were to (a) determine the effectiveness of clinician-initiated interventions for CRF and identify their mediators and (b) describe the frequency and effectiveness of patient-initiated physical activity (PA) behavior for alleviating CRF and identify determinants of this PA.

METHODS

Data (patient-reported somatic and mood symptoms; clinical data; clinician-documented changes in medication and behavior) from n = 213 patients collected as part of the clinic's standard of care at initial clinical consult and follow-up 4 to 11 weeks later were included. Effects of clinician-initiated interventions and patient-initiated PA on change in fatigue were analyzed using linear models.

RESULTS

Of all clinician-initiated interventions, only psychostimulant start was recorded frequent enough for further investigation and was associated with reduced fatigue; this association was mediated by a reduction in apathy. PA was also associated with reduced fatigue severity. PA initiation/increase after consult was associated with lower apathy at consult.

CONCLUSIONS

These results demonstrate a major role for patient apathy in the effectiveness and initiation of CRF-targeting interventions. Behavioral therapies focusing on reduction in apathy should be considered as initial treatment of CRF in those with substantial apathy.

Clinical and demographic correlates of apathy in Parkinson's disease

OBJECTIVE

To better understand the demographic, neuropsychiatric, cognitive, and motor predictors of apathy in Parkinson's disease (PD).

METHOD

112 participants (M_age = 68.53 years; M_{disease duration} = 6.17 years) were administered the Apathy Scale (AS), Beck Depression Inventory-II (BDI-II), Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Trail Making Test (TMT), Wechsler Adult Intelligence Scale-IV Matrix Reasoning subtest, letter (F-A-S) and category (Animals) fluency, and Hopkins Verbal Learning Test-Revised. Psychosis was assessed. A stepwise logistic regression analysis was performed to investigate the ability of demographic factors and clinical assessments to predict nonapathetic (AS ≤ 13) versus apathetic (AS > 13) group membership.

RESULTS

The regression analysis yielded a robust model in which older age, less education, elevated BDI-II, current psychosis, higher MDS-UPDRS Part III (motor score), and slower TMT-B performance predicted membership in the apathetic group, with a correct classification rate of 77.5% (Nagelkerke R² = 0.48, p < .001). Depression (OR = 9.20, p < .001) and education (OR = 0.66, p = 0.002) contributed significantly to the overall model. A linear regression with AS score as the outcome variable was similar, but TMT-B additionally contributed significantly (p = 0.02) to the overall model, F(6, 86) = 12.02, p < .001, adjusted R² = 0.42.

CONCLUSIONS

Of the factors examined, depression, education, and executive functioning were the strongest correlates of apathy in PD. These results support the idea that common underlying frontosubcortical disruptions in this population contribute to apathy, depression, and executive dysfunction.