Objective

We conducted a neuroimaging analysis to understand the neuroanatomical correlates of gray matter loss in a group of mild cognitive impairment and early Alzheimer's disease patients who developed delusions.

Methods

With data collected as part of the Alzheimer's Disease Neuroimaging Initiative, we conducted voxel-based morphometry to determine areas of gray matter change in the same Alzheimer's Disease Neuroimaging Initiative participants, before and after they developed delusions.

Results

We identified 14 voxel clusters with significant gray matter decrease in patient scans post-delusional onset, correcting for multiple comparisons (false discovery rate, p < 0.05). Major areas of difference included the right and left insulae, left precuneus, the right and left cerebellar culmen, the left superior temporal gyrus, the right posterior cingulate, the right thalamus, and the left parahippocampal gyrus.

Conclusions

Although contrary to our initial predictions of enhanced right frontal atrophy, our preliminary work identifies several neuroanatomical areas, including the cerebellum and left posterior hemisphere, which may be involved in delusional development in these patients.

Background

Psychotic symptoms are common in Alzheimer's disease (AD) and related neurodegenerative disorders and are associated with more rapid disease progression and increased mortality. It is unclear to what degree existing criteria are utilized in clinical research and practice.

Objective

To establish research criteria for the diagnosis of psychosis in AD.

Methods

The International Society to Advance Alzheimer's Research and Treatment (ISTAART) Neuropsychiatric Symptoms (NPS) Professional Interest Area (PIA) psychosis subgroup reviewed existing criteria for psychosis in AD and related dementias. Through a series of in person and on-line meetings, a priority checklist was devised to capture features necessary for current research and clinical needs. PubMed, Medline and other relevant databases were searched for relevant criteria.

Results

Consensus identified three sets of criteria suitable for review including those of Jeste and Finkel, Lyketsos, and the Diagnostic and Statistical Manual for Mental Disorders, 5th edition. It was concluded that existing criteria could be augmented by including a more specific differentiation between delusions and hallucinations, address overlap with related conditions (agitation in particular), adding the possibility of symptoms emerging in the preclinical and prodromal phases, and building on developing research in disease biomarkers.

Conclusion

We propose criteria, developed to improve phenotypic classification of psychosis in AD, and advance the research agenda in the field to improve epidemiological, biomarker, and genetics research in the field. These criteria serve as a complement to the International Psychogeriatric Association criteria for psychosis in neurocognitive disorders.

Psychosis is common among individuals with neurocognitive disorders, is difficult to manage, and causes considerable burden and stress to patients and caregivers. Developing effective treatments is a substantial unmet medical need but research has been slowed by the need for updated consensus diagnostic criteria. To address this need, the International Psychogeriatrics Association initiated a process to develop criteria for clinical use, research, and treatment development efforts. The process included clinical, regulatory, and industry stakeholders as well as input from a global network of experts in geriatric psychiatry responding to two surveys (N = 336). Results from the consensus process confirmed that clinicians wanted elaboration of aspects of the definition proposed by Jeste and Finkel in 2000 to ensure that the criteria are applied appropriately. Based on discussions, the survey, and emerging research, criteria were revised to apply to psychosis occurring with all major and mild neurocognitive disorders. Other important changes include providing examples of hallucinations and delusions and clarifying time course, impact, and exclusionary criteria. This definition of psychosis in major and mild neurocognitive disorders can be used to advance many types of research including development of much needed pharmacologic and nonpharmacologic interventions for psychosis in patients with neurocognitive disorders.