Clinical characteristics of hoarding disorder in Japanese patients.

Previous studies have reported clinical characteristics of hoarding disorder (HD), such as early onset, a chronic course, familiality, high unmarried rate, and high rates of comorbidities. However, clinical research targeting Japanese HD patients has been very limited. As a result, there is a low recognition of HD in Japan, leading to insufficient evaluation and treatment of Japanese HD patients. The aim of the current study was to delineate the clinical characteristics of Japanese HD patients. Thirty HD patients, 20 obsessive-compulsive disorder (OCD) patients, and 21 normal controls (NC) were targeted in this study. The HD group had a tendency toward higher familiality, earlier onset, and longer disease duration compared to the OCD group. In addition, the HD group showed a significantly higher unmarried rate than the NC group. The top two comorbidities in the HD group were major depressive disorder (56.7%) and attention-deficit/hyperactivity disorder (26.7%). The HD group had significantly higher scores on hoarding rating scales and lower scores on the Global Assessment of Functioning Scale than the other two groups. The current study showed a clinical trend in Japanese HD patients similar to previous studies in various countries, suggesting that HD may be a universal disease with consistent clinical symptoms.

Dysfunction between dorsal caudate and salience network associated with impaired cognitive flexibility in obsessive-compulsive disorder: A resting-state fMRI study.

BACKGROUND: Impaired cognitive flexibility has been implicated in the genetic basis of obsessive-compulsive disorder (OCD). Recent endophenotype studies of OCD showed neural inefficiency in the cognitive control network and interference by the limbic network of the cognitive control network. Exploring the relationship between the functional brain network and impaired cognitive flexibility may provide novel information about the neurobiological basis of OCD. METHODS: We obtained resting-state functional magnetic resonance imaging (rsfMRI) scans and measured the cognitive flexibility of 37 medication-free OCD patients and 40 healthy control (HC) participants using the Wisconsin Card Sorting Test (WCST). We explored the difference between OCD and HC groups in the functional brain network related to impaired cognitive flexibility from the amygdala and dorsal striatal regions of interest (ROIs) by using a seed-based approach. RESULTS: Significant differences between the OCD and HC groups were identified in the resting state functional network from the dorsal caudate. Increased functional connectivity from the dorsal caudate to the dorsal anterior cingulate cortex (dACC) and anterior insula (AI) was associated with poorer cognitive flexibility in the OCD group, but better cognitive flexibility in the HC group. CONCLUSIONS: These results provide evidence that the impaired cognitive flexibility of OCD may be associated with dysfunctions of the brain network from the dorsal caudate (DC) to important nodes of the salience network. Our results extend the neuropsychological model of OCD by showing intrinsically different associations between OCD and HC in functional network and cognitive flexibility.

A unique increase in prefrontal gray matter volume in hoarding disorder compared to obsessive-compulsive disorder.

BACKGROUND: Hoarding disorder (HD) is a disease concept newly presented in DSM-5. As far as we know, no studies have examined the structural changes relevant to hoarding by applying the diagnostic criteria of HD in DSM-5. In the present study, we aimed to find abnormalities in gray matter (GM) structures of patients with HD. METHODS: Seventeen patients who met the DSM-5 criteria for HD, 17 obsessive-compulsive disorder (OCD) patients, and 17 healthy controls (HCs) participated in this study. All participants underwent MRI scanning of the brain by a 3.0-Tesla MRI scanner. In a voxel-based morphometric procedure, preprocessed GM structural images were used to compare the three groups. Thereafter we investigated the correlation between the clinical data (age of onset, symptomatic severity) and GM volume. RESULTS: The HD group showed a significantly increased GM volume compared to the OCD and healthy control groups (p<0.05) in both Brodmann area (BA)10 and BA11. There was no significant difference between OCD and healthy control groups. No significant correlation between the clinical data including age of onset, symptom severity score, and GM volume was observed in HD and OCD groups. CONCLUSIONS: The results might help to explain the inconsistency of previous studies. As with OCD, HD is considered to have cognitive dysfunction as its basis. This result is convincing after considering the clinical features of HD and suggested that structural abnormalities in the prefrontal regions might relate to the pathophysiology of HD.

A transcultural study of hoarding disorder: Insights from the United Kingdom, Spain, Japan, and Brazil.

Though problematic hoarding is believed to be a universal human behavior, investigations of clinically-defined hoarding disorder (HD) have been confined almost exclusively to Western countries. The current investigation sought to describe and directly compare the features of individuals meeting diagnostic criteria for HD across four distinct cultural settings. Participants were 82 individuals meeting DSM-5 diagnostic criteria for HD, recruited and assessed by trained clinicians at one of four project sites: London, Barcelona, Fukuoka, and Rio de Janeiro. A series of semi-structured interviews and self-report scales were administered, including assessments of socio-demographic characteristics, psychiatric comorbidity, and severity of hoarding and related features. Results indicate that the severity and core features of HD, as well as the cognitions and behaviors commonly associated with this condition, are largely stable across cultures. However, some differences in patient demographics-in particular age, marital status, and clinical expression-as well as comorbid psychiatric features also emerged. These findings confirm that HD, as defined in DSM-5, exists and presents with similar phenomenology across the studied cultures. Future, more fine-grained, research will be needed to study the features of the disorder in additional cultures (e.g., non-industrialized nations) and to evaluate the impact of these cultural aspects on the design of interventions for the disorder.

A pilot study exploring the association of morphological changes with 5-HTTLPR polymorphism in OCD patients.

BACKGROUND: Clinical and pharmacological studies of obsessive-compulsive disorder (OCD) have suggested that the serotonergic systems are involved in the pathogenesis, while structural imaging studies have found some neuroanatomical abnormalities in OCD patients. In the etiopathogenesis of OCD, few studies have performed concurrent assessment of genetic and neuroanatomical variables. METHODS: We carried out a two-way ANOVA between a variable number of tandem repeat polymorphisms (5-HTTLPR) in the serotonin transporter gene and gray matter (GM) volumes in 40 OCD patients and 40 healthy controls (HCs). RESULTS: We found that relative to the HCs, the OCD patients showed significant decreased GM volume in the right hippocampus, and increased GM volume in the left precentral gyrus. 5-HTTLPR polymorphism in OCD patients had a statistical tendency of stronger effects on the right frontal pole than those in HCs. CONCLUSIONS: Our results showed that the neuroanatomical changes of specific GM regions could be endophenotypes of 5-HTTLPR polymorphism in OCD.