Prevalence of possible idiopathic normal pressure hydrocephalus in older inpatients with schizophrenia: a replication study

Abstract

Background: We recently reported that older patients with schizophrenia (SZ) show possible idiopathic normal pressure hydrocephalus (iNPH) more frequently than the general population. In this study, we estimated the prevalence of iNPH in a larger number of older SZ patients and explored useful examination values for diagnosis in the SZ population. Methods: We enrolled older inpatients with SZ (n = 39, mean age = 68.6 ± 7.7 years) from several psychiatric hospitals in Ehime, Japan and acquired brain imaging data using computed tomography. We evaluated three iNPH symptoms (dementia, gait disturbance, and urinary incontinence). In addition, we combined these data with our previous data to elucidate the relationship between iNPH and characteristics of SZ symptoms. Results: In total, five (12.8%) patients were diagnosed with possible iNPH. Evans' index for patients with iNPH was significantly higher than for those without iNPH (p = 0.002). The number of disproportionately enlarged subarachnoid space hydrocephalus (DESH) findings was significantly higher in patients with iNPH than in those without iNPH (p < 0.001). Using combined data, Drug-Induced Extra-pyramidal Symptoms Scale (DIEPSS) subscales of gait and bradykinesia showed an increasing trend in the SZ with iNPH group. Conclusions: We reconfirmed that older inpatients with SZ experienced possible iNPH more frequently than the general population. We should pay attention to the DIEPSS subscales of gait and bradykinesia and DESH findings in addition to the three main symptoms of iNPH and Evans' index so as to not miss SZ patients with iNPH.

The impact of neurocognitive and psychiatric disorders on the risk of idiopathic normal pressure hydrocephalus: A bidirectional Mendelian randomization study

“…A widely accepted consensus posits that the enlargement of brain ventricles in iNPH is associated with compromised CSF homeostasis (Wang et al, 2020). Additionally, previous studies have demonstrated that iNPH frequently coexists with these neurocognitive and psychiatric disorders, promoting a further exploration of the potential associations that were not previously elucidated (Yoshino et al, 2020;Israelsson et al, 2016;Kito et al, 2009). The presence of comorbid PD or PD dementia has been shown to exacerbate the clinical course of iNPH, underscoring the need to unravel the potential association between iNPH and PD for more informed treatment planning (Sakurai et al, 2022).…”

“…Additionally, iNPH commonly presents concomitantly with psychiatric disorders in elderly individuals, including depression, anxiety, and schizophrenia (SCZ) (Israelsson et al., 2016 ; Kito et al., 2009 ; Yoshino et al., 2020 ). A more frequent possibility of iNPH in older patients with SCZ than in the general population has been reported (Yoshino et al., 2020 ). Moreover, a prior investigation demonstrated that iNPH patients were more prone to have a positive depression screen and a history of psychiatric disorders (Ghaffari‐Rafi et al., 2020 ).…”

“…In MR analysis, based on the data of genome‐wide association studies (GWAS), single nucleotide polymorphisms (SNPs) associated with exposure are leveraged as instrumental variables (IVs) to assess causality between exposure and outcome. It is crucial to note that, although neurocognitive and psychiatric disorders may coexist with iNPH in some cases, the direct causal relationships between them remain unclear (Lim et al., 2014 ; Yoshino et al., 2020 ).…”

“…These similarities in clinical presentations further complicate the understanding of the relationships between these conditions. Additionally, iNPH commonly presents concomitantly with psychiatric disorders in elderly individuals, including depression, anxiety, and schizophrenia (SCZ) (Israelsson et al, 2016;Kito et al, 2009;Yoshino et al, 2020). A more frequent possibility of iNPH in older patients with SCZ than in the general population has been reported (Yoshino et al, 2020).…”

Idiopathic Intracranial Hypertension with Disproportionately Enlarged Subarachnoid Space Hydrocephalus on Imaging

“…The pathomechanisms underlying IIH and iNPH are not fully understood, and many reports suggest that a combination of several factors is involved ( 1 , 10 ). Venous sinus stenosis, metabolic disorders, obesity-induced elevated inflammatory cytokines, and impaired venous return are reported to be risk factors for IIH ( 1 ), while cerebrovascular disease and schizophrenia are reported to be risk factors for iNPH ( 4 , 11 ). The involvement of CSF efflux mechanisms, such as the glymphatic system ( 12 ), has been proposed as a common pathology in both diseases ( 13 , 14 ).…”