Episodic memory deficit in elderly adults with suspected delusional disorder

Phenotypic cognitive impairment in late-onset delusional disorder

BACKGROUND

Previous use of heterogeneous diagnostic criteria and insensitive cognitive measures has impeded clarification of the extent and type of cognitive impairment specific to late-onset delusional disorder. We examined whether clinical presentations of late-onset delusional disorder are associated with prodromal or established dementia, and whether it might be a discrete clinical syndrome characterized by its own profile of cognitive impairment.

METHOD

Nineteen patients with late-onset delusional disorder from a hospital psychiatric service and 20 patients with dementia of the Alzheimer's type (AD) from an outpatient memory clinic were recruited in a consecutive case series. All patients underwent comprehensive neuropsychological assessment that included general intellectual function, executive function, new learning and delayed memory, language, processing speed, and visuo-perceptual skills.

RESULTS

Late-onset delusional disorder patients showed moderate impairment to conceptual reasoning, visual object recognition, processing speed, and confrontation naming. Severe impairment appeared in visuo-perceptual planning and organization, and divided attention. Compared with the Alzheimer's disease (AD) group, the late-onset delusional disorder group demonstrated significantly poorer visuo-perceptual skills but a significantly better capacity to consolidate information into delayed memory.

CONCLUSIONS

A high rate of marked cognitive impairment occurs in late-onset delusional disorder. There was evidence of a conceptual reasoning deficit, plus the presence of a visuo-perceptual impairment affecting object recognition. This impairment profile can explain the genesis and maintenance of the observed delusions. Understanding late-onset delusional disorder as other than a purely psychiatric phenomenon or a precursor to AD will lead to better assessment and management approaches.

Deficits in executive and memory processes in delusional disorder: a case-control study

OBJECTIVE

Delusional disorder has been traditionally considered a psychotic syndrome that does not evolve to cognitive deterioration. However, to date, very little empirical research has been done to explore cognitive executive components and memory processes in Delusional Disorder patients. This study will investigate whether patients with delusional disorder are intact in both executive function components (such as flexibility, impulsivity and updating components) and memory processes (such as immediate, short term and long term recall, learning and recognition).

METHODS

A large sample of patients with delusional disorder (n = 86) and a group of healthy controls (n = 343) were compared with regard to their performance in a broad battery of neuropsychological tests including Trail Making Test, Wisconsin Card Sorting Test, Colour-Word Stroop Test, and Complutense Verbal Learning Test (TAVEC).

RESULTS

When compared to controls, cases of delusional disorder showed a significantly poorer performance in most cognitive tests. Thus, we demonstrate deficits in flexibility, impulsivity and updating components of executive functions as well as in memory processes. These findings held significant after taking into account sex, age, educational level and premorbid IQ.

CONCLUSIONS

Our results do not support the traditional notion of patients with delusional disorder being cognitively intact.

Empirical redefinition of delusional disorder and its phenomenology: the DELIREMP study

AIMS

Since Kraepelin, the controversy has persisted surrounding the nature of delusional disorder (DD) as a separate nosological entity or its clinical subtypes. Nevertheless, there has been no systematic study of its psychopathological structure based on patient interviews. Our goal was to empirically explore syndromic subentities in DD.

METHODS

A cross-sectional study was conducted in 86 outpatients with DSM-IV-confirmed DD using SCID-I. Psychopathological factors were identified by factor analysis of PANSS scores. The association between these factors and clinical variables (as per standardized instruments) was analyzed using uni- and multivariate techniques.

RESULTS

PANSS symptoms were consistent with four factors (Paranoid, Cognitive, Schizoid, and Affective dimensions), accounting for 59.4% of the total variance. The Paranoid Dimension was associated with premorbid paranoid personality disorder, more adverse childhood experiences, chronic course, legal problems, worse global functioning, and poorer treatment adherence and response. The Cognitive Dimension was associated with poorer cognitive functioning, premorbid substance abuse, comorbid somatic diseases, mainly non-prominent visual hallucinations, fewer comorbid depressive disorders, and poorer global functioning. The Schizoid Dimension was associated with being single, a family history of schizophrenia, premorbid personality disorders (largely schizoid and schizotypal), non-prominent auditory hallucinations, and dysthymia. Finally, the Affective Dimension was associated with a family history of depression, premorbid obsessive personality, somatic delusions, absence of reference delusions, tactile and olfactory hallucinations, depressive and anxiety disorders, risk of suicide, and higher perceived stress.

CONCLUSION

The identification and clinical validation of four separate psychopathological dimensions in DD provide evidence toward a more accurate conceptualization of DD and its types.

A preclinical cognitive test battery to parallel the National Institute of Health Toolbox in humans: bridging the translational gap

A major goal of animal research is to identify interventions that can promote successful aging and delay or reverse age-related cognitive decline in humans. Recent advances in standardizing cognitive assessment tools for humans have the potential to bring preclinical work closer to human research in aging and Alzheimer's disease. The National Institute of Health (NIH) has led an initiative to develop a comprehensive Toolbox for Neurologic Behavioral Function (NIH Toolbox) to evaluate cognitive, motor, sensory and emotional function for use in epidemiologic and clinical studies spanning 3 to 85 years of age. This paper aims to analyze the strengths and limitations of animal behavioral tests that can be used to parallel those in the NIH Toolbox. We conclude that there are several paradigms available to define a preclinical battery that parallels the NIH Toolbox. We also suggest areas in which new tests may benefit the development of a comprehensive preclinical test battery for assessment of cognitive function in animal models of aging and Alzheimer's disease.

Neuropsychological research in delusional disorder: a comprehensive review

In recent decades, there has been a growing interest in the field of delusions, and different aspects of delusional disorder (DD) have been investigated. However, DD is still one of the most underresearched psychiatric disorders. In this paper, we review the literature on DD and most of the theoretical approaches proposed to explain the development and maintenance of delusions. DD research is infrequent, and delusions in this disorder have been scarcely investigated. We aim to establish the state of the art of delusions research to date and point to the shortage of neuropsychological studies in patients with DD. We also justify the need for future research into the neuropsychological correlates of DD as measured in patients with this disorder given that most previous research has mainly focused on other psychotic conditions.

A comparative study of cognitive deficits in patients with delusional disorder and paranoid schizophrenia

BACKGROUND

Very few studies have evaluated the neurocognitive functions of patients with persistent delusional disorder.

AIM

To study the neurocognitive profile of patients with delusional disorder and compare it with those of patients with paranoid schizophrenia and healthy control subjects.

MATERIALS AND METHODS

Attention concentration, executive functions, memory, and IQ were assessed in 20 patients with delusional disorder and were compared with 20 patients with paranoid schizophrenia and 20 healthy controls. All three groups were matched on age, sex, and level of education. The two patient groups were also matched on duration of illness.

RESULTS

In general, patients with delusional disorder performed worst than healthy controls and patients with paranoid schizophrenia performed in between the other two groups. Compared with healthy controls, both patients with delusional disorder and patients with paranoid schizophrenia were significantly impaired on different tests of attention and visual learning and memory. Compared with patients with paranoid schizophrenia, patients with delusional disorder had more impairment different tests of attention, visual learning and memory, verbal working memory, and executive functions.

CONCLUSION

Patients with delusional disorder exhibit cognitive dysfunctions that are very similar to schizophrenia, but are more severe in intensity. The resemblance of cognitive profiles suggests that the two disorders may have similar etiological basis.

Cognitive neuroscience of delusions in aging

Assessments and clinical understanding of late-onset delusions in the elderly are inconsistent and often incomplete. In this review, we consider the prevalence, neurobehavioral features, and neuroanatomic correlations of delusions in elderly persons - those with documented cognitive decline and those with no evidence of cognitive decline. Both groups exhibit a common phenotype: delusions are either of persecution or of misidentification. Late-onset delusions show a nearly complete absence of the grandiose, mystical, or erotomanic content typical of early onset psychoses. Absent also from both elderly populations are formal thought disorders, thought insertions, and delusions of external control. Neuroimaging and behavioral studies suggest a frontotemporal localization of delusions in the elderly, with right hemispheric lateralization in delusional misidentification and left lateralization in delusions of persecution. We propose that delusions in the elderly reflect a common neuroanatomic and functional phenotype, and we discuss applications of our proposal to diagnosis and treatment.

Erotomania : epidemiology and management

Erotomania is generally classified as a delusional disorder in contemporary classification systems (DSM-IV and ICD-10). The incidence of erotomania is not known, but that of delusional disorder in general has been reported as approximately 15 cases per 100,000 of the population per year, with a female : male ratio of 3 : 1. Both primary and secondary types of erotomania have been identified, the latter being associated with evidence of an aetiologically significant organic or psychiatric condition. The aetiology of primary erotomania is not yet fully understood, but neuroimaging, genetic studies and findings from evolutionary psychopathology hold considerable promise for a deeper and broader understanding of this condition. The initial management of secondary erotomania focuses on treating the underlying organic or psychiatric illness. The management of primary and secondary erotomania involves a combination of pharmacological treatments, psychosocial interventions and risk management strategies. In the past, the antipsychotic medication pimozide was commonly used, at least in certain countries (such as the US and Canada), despite a paucity of systematic studies of its use in this disorder. In recent years, there have been reports of positive therapeutic outcomes with atypical antipsychotics (risperidone, clozapine), which, as a result of their improved tolerability over older agents such as pimozide, will hopefully enhance patient acceptability and, thereby, improve clinical outcome. Despite this advance, there is still a strong need for controlled clinical trials of therapeutic strategies for primary erotomania and related syndromes.

Impairment in visual and spatial perception in schizophrenia and delusional disorder

The Judgment of Line Orientation Test, a visuospatial processing task, was administered to normal subjects, to schizophrenic patients and to patients with delusional disorder. Significantly better performance was seen in the normal subjects than in the schizophrenic and delusional patients. Delusional patients, in turn, showed better performance than the schizophrenic patients.

Elderly patients with major depressive disorder and delusional disorder are at increased risk of subsequent dementia

All the patients (n=150) admitted to psychogeriatric clinic during a 1-year period were followed up until their death or for 10 years. Fifteen of these were lost during the 10-year follow-up. Thus, follow-up data were available for 135 patients. Twenty-four of these fulfilled at baseline the DSM-III-R diagnostic criteria of major depressive disorder and 18 of delusional disorder after careful medical examination and neuropsychological tests to eliminate organic causes. In the follow-up, the diagnoses were gathered from the death certificates of those patients who died during the 10-year period and all of the patients alive at the end of the study were interviewed to assess their mental state. Six out of the 24 (25%) patients with major depressive and five out of 18 (28%) patients with delusional disorder developed clear organic dementia before death or within 10 years (mean follow-up time 6.7 years). This is approximately double the expected incidence in the general population of that age. The gender, age at index admission, the baseline Mini Mental State Examination scores or findings in computer tomography did not contribute to the risk of dementia. Psychogeriatric patients admitted due to major mental disorder may have an increased risk of organic dementia in the near future.

Testing episodic memory in animals: a new approach

Episodic memory involves the encoding and storage of memories concerned with unique personal experiences and their subsequent recall, and it has long been the subject of intensive investigation in humans. According to Tulving's classical definition, episodic memory "receives and stores information about temporally dated episodes or events and temporal-spatial relations among these events." Thus, episodic memory provides information about the 'what' and 'when' of events ('temporally dated experiences') and about 'where' they happened ('temporal-spatial relations'). The storage and subsequent recall of this episodic information was thought to be beyond the memory capabilities of nonhuman animals. Although there are many laboratory procedures for investigating memory for discrete past episodes, until recently there were no previous studies that fully satisfied the criteria of Tulving's definition: they can all be explained in much simpler terms than episodic memory. However, current studies of memory for cache sites in food-storing jays provide an ethologically valid model for testing episodic-like memory in animals, thereby bridging the gap between human and animal studies memory. There is now a pressing need to adapt these experimental tests of episodic memory for other animals. Given the potential power of transgenic and knock-out procedures for investigating the genetic and molecular bases of learning and memory in laboratory rodents, not to mention the wealth of knowledge about the neuroanatomy and neurophysiology of the rodent hippocampus (a brain area heavily implicated in episodic memory), an obvious next step is to develop a rodent model of episodic-like memory based on the food-storing bird paradigm. The development of a rodent model system could make an important contribution to our understanding of the neural, molecular, and behavioral mechanisms of mammalian episodic memory.

Episodic and declarative memory: role of the hippocampus

The fact that medial temporal lobe structures, including the hippocampus, are critical for declarative memory is firmly established by now. The understanding of the role that these structures play in declarative memory, however, despite great efforts spent in the quest, has eluded investigators so far. Given the existing scenario, novel ideas that hold the promise of clarifying matters should be eagerly sought. One such idea was recently proposed by Vargha-Khadem and her colleagues (Science 1997; 277:376-380) on the basis of their study of three young people suffering from anterograde amnesia caused by early-onset hippocampal pathology. The idea is that the hippocampus is necessary for remembering ongoing life's experiences (episodic memory), but not necessary for the acquisition of factual knowledge (semantic memory). We discuss the reasons why this novel proposal makes good sense and why it and its ramifications should be vigorously pursued. We review and compare declarative and episodic theories of amnesia, and argue that the findings reported by Vargha-Khadem and her colleagues fit well into an episodic theory that retains components already publicized, and adds new ones suggested by the Vargha-Khadem et al. study. Existing components of this theory include the idea that acquisition of factual knowledge can occur independently of episodic memory, and the idea that in anterograde amnesia it is quite possible for episodic memory to be more severely impaired than semantic memory. We suggest a realignment of organization of memory such that declarative memory is defined in terms of features and properties that are common to both episodic and semantic memory. The organization of memory thus modified gives greater precision to the Vargha-Khadem et al. neuroanatomical model in which declarative memory depends on perihippocampal cortical regions but not on the hippocampus, whereas episodic memory, which is separate from declarative memory, depends on the hippocampus.