Kentaro Kawabe

Internet addiction: Prevalence and relation with mental states in adolescents

Internet addiction disrupts the daily lives of adolescents. We investigated the prevalence of Internet addiction in junior high school students, elucidated the relation between Internet addiction and mental states, and determined the factors associated with Internet addiction in adolescents.

TREM2 mRNA Expression in Leukocytes Is Increased in Alzheimer’s Disease and Schizophrenia

TREM2 and TYROBP are causal genes for Nasu–Hakola disease (NHD), a rare autosomal recessive disease characterized by bone lesions and early-onset progressive dementia. TREM2 forms a receptor signaling complex with TYROBP, which triggers the activation of immune responses in macrophages and dendritic cells, and the functional polymorphism of TREM2 is reported to be associated with neurodegenerative disorders such as Alzheimer’s disease (AD). The objective of this study was to reveal the involvement of TYROBP and TREM2 in the pathophysiology of AD and schizophrenia. Methods: We investigated the mRNA expression level of the 2 genes in leukocytes of 26 patients with AD and 24 with schizophrenia in comparison with age-matched controls. Moreover, we performed gene association analysis between these 2 genes and schizophrenia. Results: No differences were found in TYROBP mRNA expression in patients with AD and schizophrenia; however, TREM2 mRNA expression was increased in patients with AD and schizophrenia compared with controls (P < 0.001). There were no genetic associations of either gene with schizophrenia in Japanese patients. Conclusion: TREM2 expression in leukocytes is elevated not only in AD but also in schizophrenia. Inflammatory processes involving TREM2 may occur in schizophrenia, as observed in neurocognitive disorders such as AD. TREM2 expression in leukocytes may be a novel biomarker for neurological and psychiatric disorders.

Age- and sex-related emotional and behavioral problems in children with autism spectrum disorders: Comparison with control children

Children with autism spectrum disorders (ASD) often present with emotional and behavioral problems, which could change the clinical course, especially during childhood, and affect future quality of life. The aim of this study was to clarify the age‐ and sex‐related differences of these problems in ASD.

The Melatonin Receptor Agonist Ramelteon Effectively Treats Insomnia and Behavioral Symptoms in Autistic Disorder

Children with autism spectrum disorders (ASD), including autistic disorder, frequently suffer from comorbid sleep problems. An altered melatonin rhythm is considered to underlie the impairment in sleep onset and maintenance in ASD. We report three cases with autistic disorder in whom nocturnal symptoms improved with ramelteon, a selective melatonin receptor agonist. Insomnia and behavior, assessed using the Clinical Global Impression-Improvement Scale, improved in two cases with 2 mg ramelteon and in the third case with 8 mg ramelteon. Our findings demonstrate that ramelteon is effective not only for insomnia, but for behavioral problems as well, in patients with autistic disorder.

Elevated TREM2 mRNA expression in leukocytes in schizophrenia but not major depressive disorder

The pathological mechanisms of schizophrenia (SCZ) have not been clarified, but the microglia hypothesis has recently been discussed. We previously reported that the mRNA for a protein related to activation of microglia, triggering receptor expressed on myeloid cell 2 (TREM2), is expressed higher in peripheral leukocytes in SCZ than controls. In this study, we analyzed TREM2 mRNA expression in leukocytes from both SCZ and major depressive disorder (MDD) patients. We compared 50 SCZ patients and 42 MDD patients with age-matched controls. Levels of TREM2 mRNA in leukocytes were analyzed with quantitative real-time PCR method using TaqMan probe. TREM2 mRNA expression was significantly higher in leukocytes of SCZ subjects than controls, but the expression level was non-significantly different in MDD subjects. We observed a decrease in TREM2 mRNA expression in leukocytes from one SCZ patient after clozapine treatment. The expression did not change following ECT, but the expression level in this patient was still significantly higher than that in controls. We conclude that the high amount of TREM2 mRNA expression in leukocytes is specific to SCZ but not MDD and that changes in TREM2 mRNA expression may be a trait biomarker for SCZ.

Effects of Adenotonsillectomy on Neurocognitive Function in Pediatric Obstructive Sleep Apnea Syndrome

Obstructive sleep apnea syndrome (OSAS) in children does not only present with symptoms of sleep disturbances but also with associated symptoms such as growth failure, enuresis, academic learning difficulties, and behavioral problems, including attention deficit/hyperactivity disorder- (ADHD-) like symptoms. We evaluated neurocognitive functions before and after adenotonsillectomy in a patient with OSAS. An 11-year-old boy suspected of having ADHD with nocturnal enuresis was referred for evaluation. He was found to have adenotonsillar hypertrophy. Presence of snoring was evident only after detailed medical interview. Polysomnography confirmed the diagnosis of OSAS, which was subsequently treated by adenotonsillectomy. The apnea/hypopnea index decreased from 21.9 at baseline to 1.8 after surgery, and the frequency of enuresis fell from almost nightly to 2-3 times per month. Neurocognitive and behavioral assessment after the treatment of OSAS showed significant improvement in cognitive functions, especially attention capacity and considerable amelioration of behavioral problems including ADHD-like symptoms. As the most common cause of pediatric OSAS is adenotonsillar hypertrophy, medical interview and oropharyngeal examination should always be performed in children suspected of having ADHD. The necessity of sleep evaluation for children with ADHD-like symptoms was also emphasized.

A case study: neuroleptic malignant syndrome with risperidone and CYP2D6 gene variation.

We present a schizophrenic patient who experienced neuroleptic malignant syndrome with risperidone treatment due to variants of the CYP2D6 gene with reduced function. Clinicians need to be aware of this potential complication.

Low methylation rates of dopamine receptor D2 gene promoter sites in Japanese schizophrenia subjects.

Abstract Objectives: According to the dopamine hypothesis, several studies on the gene for the dopamine receptor D2 (DRD2) have been conducted. However, no trait biomarkers on DRD2 are available. We examined whether the methylation rates in the upstream region of DRD2 in leukocytes are different in schizophrenia (SCZ) subjects compared to control subjects. Methods: We selected seven CpG sites in the upstream region of DRD2 that may theoretically bind major transcription factors. The methylation rates in these regions of 50 medicated and 18 drug-naïve SCZ subjects were compared with those of age-matched control subjects. Results: The methylation rates were significantly lower in medicated (CpG2, P < 0.0001; CpG4, P = 0.013; CpG7, P < 0.0001; and average: 12.9 ± 1.8 vs. 14.1 ± 2.2, P = 0.005) and drug-naïve SCZ subjects (CpG1, P = 0.006; CpG2, P = 0.001; CpG3, P = 0.001; CpG5, P = 0.02; CpG6, P = 0.015; CpG7, P = 0.027; and average: 9.86 ± 0.9 vs. 11.2 ± 1.3, P = 0.002). Conclusions: We confirmed low methylation rates in the upstream region of DRD2 in both medicated and drug-naïve SCZ subjects. Low methylation rates of DRD2 in leukocytes may be a trait biomarker for SCZ.

Developmental quotient to estimate intelligence in autism spectrum disorder.

Autism spectrum disorders (ASD) are characterized by persistent deficits in social communication and social interaction across contexts, and are associated with restricted patterns of behavior. The developmental quotient (DQ) is based on the developmental age and chronological age of children. This study investigated the utility of the DQ to estimate cognitive ability in young children with ASD.

Metabolic status and resistin in chronic schizophrenia over a 2-year period with continuous atypical antipsychotics

Background: Common adverse effects of atypical antipsychotic treatments for schizophrenia are weight gain and lipid metabolism abnormality. We aimed to identify the signs of metabolic problems with continuous atypical antipsychotic treatment for schizophrenia over a 2-year period. Methods: The participants were 68 schizophrenic patients (29 males, 39 females; ages 53.4 ± 13.5 years old). Changes in carbohydrate metabolism and changes in physical characteristics were studied over a 2-year period. In addition, functional single nucleotide polymorphisms in the transcriptional regulatory region of the resistin gene were examined. Results: We found no changes in the mental state of the participants over a 2-year period. Patients did show a significant decrease in total cholesterol and hemoglobin A1c levels, although physical changes such as body mass index and abdominal girth, were not observed. The amount of resistin may not be associated with mental states and physical parameters. Conclusions: We could not find physical factors related to metabolic changes of antipsychotics in this 2-year study. However, several psychological factors, such as health-related thoughts and behaviors, should be studied in the future.