Brain structural changes and neuropsychological impairments in male polydipsic schizophrenia

Polydipsia and autistic traits in patients with schizophrenia spectrum disorders

Introduction

Polydipsia, prevalent in 6%-20% of patients with schizophrenia, results in seclusion and prolonged hospitalization. It is also observed in autistic individuals, with previous studies reporting that autism accounted for 20% of all hospitalized patients with polydipsia. The current study investigated the association between polydipsia and autistic traits in patients with schizophrenia spectrum disorders (SSDs) based on the hypothesis that higher autistic traits would be observed in schizophrenic patients with polydipsia.

Methods

In the first study (study A), the autism-spectrum quotient [(AQ); Japanese version] scores of long-stay inpatients with and without polydipsia were compared. Furthermore, the association between polydipsia and autistic traits was also examined in short-stay inpatients and outpatients with SSDs (study B).

Results

Study A showed that patients with polydipsia scored significantly higher on the three AQ subscales (attention switching; communication; and imagination) compared to those without. Study B also showed that patients with polydipsia had significantly higher AQ scores overall and for several subscales compared to those without polydipsia. Binary logistic regression analysis of the combined sample showed that male gender and higher autistic traits were significant predictors of polydipsia.

Discussion

The study highlights the importance of focusing on such traits to understand the pathogenesis of polydipsia in SSD patients.

Non-antipsychotic pharmacotherapy of psychogenic polydipsia: A systematic review

OBJECTIVE

Polydipsia is defined at the intake of excessive fluid (>3 L daily). Psychogenic polydipsia (PPD) presents without an identifiable medical cause and is often seen in patients with diagnoses of schizophrenia, OCD, anxiety, alcohol use disorder, and other psychotic disorders. The purpose of this systematic review is to assess the therapeutic effect of various non-antipsychotic medications on patients with a stable psychotic illness and concurrent PPD.

METHODS

A systematic search was conducted using the following databases: PubMed, MEDLINE with Full Text, CINAHL complete, Cochrane database of systematic reviews, Cochrane methodology register, MasterFILE Premier, APA PsychArticles, APA PsychInfo, APA PsycBooks, APA PsycTests, TRIP, Nursing and Allied Health. The quality of each retained study was assessed using appropriate risk of bias tools based on study design.

RESULTS

The initial search resulted in 1422 articles from which 22 articles were included for qualitative synthesis. Study designs ranged from case reports to double blind, placebo controlled randomized trials and was interpreted uniquely based on study design. Acetazolamide was effective in improving some PPD outcomes. Fluoxetine at high doses was effective in reducing fluid intake and polydipsia. Other medications included in this review performed equivocally for reduction of numerous parameters evaluating PPD.

CONCLUSION

No one drug appeared to be the most efficacious; however, some did show promise in specific populations. Those in need of pharmacotherapeutic options for PPD may consider one of the included agents to assist with co-morbid state. Further high-quality research is needed to provide better treatment guidance for PPD.

Association between Serum Essential Metal Elements and the Risk of Schizophrenia in China

Numerous essential metal elements (EMEs) are necessary to maintain the proper function of human body. In this case-control study, we investigated the associations of 11 EMEs [Calcium (Ca), potassium (K), magnesium (Mg), sodium (Na), manganese (Mn), selenium (Se), cobalt (Co), Molybdenum (Mo), copper (Cu), zinc (Zn), and iron (Fe)] in serum with the risk of schizophrenia. We recruited first-episode and drug-naïve schizophrenic patients (cases = 99) and age-sex-matched normal subjects (controls = 99) from Tangshan, Hebei Province, China. The 11 EMEs in serum from cases and controls were quantified by inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry. We observed that a higher level of Mn (OR = 2.390; 95%CI: 1.504–3.796) and lower levels of Ca (OR = 0.939; 95%CI: 0.890–0.990), Mg (OR = 0.806; 95%CI: 0.669–0.972), Na (OR = 0.995; 95%CI: 0.993–0.998), and Se (OR = 0.954; 95%CI: 0.937–0.972) were associated with an elevated risk of schizophrenia. Dose–response relationships between serum EME concentrations and the risk of schizophrenia were observed in most of the schizophrenia-associated EMEs. Moreover, the serum concentrations of these schizophrenia-associated EMEs in patients were correlated with the severity of their clinical symptoms. Significant correlations were found between EMEs and biomarkers associated with schizophrenia related to metabolic and oxidative stress. This study suggested that the concentration and profile of EMEs were different between schizophrenic patients and normal controls and revealed potential metabolisms associated with EMEs and schizophrenia, suggesting EMEs might act as biomarkers of schizophrenia to improve the current situation of diagnosis and treatment.

Role of Naltrexone in Improving Compulsive Drinking in Psychogenic Polydipsia

Psychogenic polydipsia or self-induced water intoxication is a potentially lethal condition seen in many chronic psychiatric patients. This is a literature review based on therapeutic significance of Naltrexone in improving compulsive water drinking behavior in chronic psychiatrically ill patients with psychogenic polydipsia. Naltrexone is an opioid antagonist approved by FDA for alcohol dependence. Extensive literature search provides a line of evidence that suggests correlation of opioid receptor with compulsive water ingestion in animals. However, there is limited data regarding clinical utility of naltrexone in improving psychogenic polydipsia in human species. This review highlights the necessity for further research and trials to elucidate the role of naltrexone in human psychogenic drinking behavior.

The Bed Nucleus of the Stria Terminalis, Homeostatic Satiety, and Compulsions: What Can We Learn From Polydipsia?

A compulsive phenotype characterizes several neuropsychiatric illnesses - including but not limited to - schizophrenia and obsessive compulsive disorder. Because of its perceived etiological heterogeneity, it is challenging to disentangle the specific neurophysiology that precipitates compulsive behaving. Using polydipsia (or non-regulatory water drinking), we describe candidate neural substrates of compulsivity. We further postulate that aberrant neuroplasticity within cortically projecting structures [i.e., the bed nucleus of the stria terminalis (BNST)] and circuits that encode homeostatic emotions (thirst, hunger, satiety, etc.) underlie compulsive drinking. By transducing an inaccurate signal that fails to represent true homeostatic state, cortical structures cannot select appropriate and adaptive actions. Additionally, augmented dopamine (DA) reactivity in striatal projections to and from the frontal cortex contribute to aberrant homeostatic signal propagation that ultimately biases cortex-dependent behavioral selection. Responding becomes rigid and corresponds with both erroneous, inflexible encoding in both bottom-up structures and in top-down pathways. How aberrant neuroplasticity in circuits that encode homeostatic emotion result in the genesis and maintenance of compulsive behaviors needs further investigation.

Association between the scores of the Japanese version of the Brief Assessment of Cognition in Schizophrenia and whole-brain structure in patients with chronic schizophrenia: A voxel-based morphometry and diffusion tensor imaging study

AIM

The Brief Assessment of Cognition in Schizophrenia (BACS) is a concise tool designed to evaluate cognitive deficits in schizophrenia. We examined the possible association between BACS scores and whole-brain structure, as observed using magnetic resonance imaging with a relatively large sample.

METHODS

The study sample comprised 116 patients with schizophrenia (mean age, 39.3 ± 11.1 years; 66 men) and 118 healthy controls (HC; mean age, 40.0 ± 13.6 years; 58 men) who completed the Japanese version of the BACS (BACS-J). All participants were of Japanese ethnicity. The magnetic resonance imaging volume and diffusion tensor imaging data were processed with voxel-based morphometry and tract-based spatial statistics, respectively.

RESULTS

There were significant reductions in the regional gray matter volumes and white matter fractional anisotropy values in patients with schizophrenia compared to HC. For the gray matter areas, the working memory score had a significant positive correlation with the anterior cingulate and medial frontal cortices volumes in the patients. For the white matter areas, the motor speed score had a significant positive correlation with fractional anisotropy values in the corpus callosum, internal capsule, superior corona radiata, and superior longitudinal fasciculus in the patients. However, there was no significant correlation among either the gray or white matter areas in the HC.

CONCLUSION

Our results suggest that among the BACS-J measures, the working memory and motor speed scores are associated with several structural alterations in the brains of patients with schizophrenia.

Hiponatremia in the practice of a psychiatrist. Part 2: psychogenic polydipsia

Objective. The study is the second part of the literature review on hyponatremia in patients with diagnosed mental disorders. This article focuses on psychogenic polydipsia as, along with the SIADH, one of the two most common causes of hyponatremia in the mentioned group of patients.

Method: The literature review was based on searching the Medline, the Google Scholar and the Ebsco databases in Polish and English by entering the following phrases: psychogenic polydipsia, the psychosis – intermittent hyponatremia – polydipsia syndrome, water intoxication.

Discussion: Psychogenic polydipsia occurs in up to 25% of patients treated for mental disorders. It most frequently concerns patients with schizophrenia. 30% of patients with psychogenic polydipsia suffer from hyponatremia with or without symptoms of water intoxication. In the etiology of psychogenic polydipsia, the influence of dopaminergic and noradrenergic neurotransmission has been considered, as well as angiotensin, which is claimed to have dipsogenic properties. In order to reduce the severity of the disorder, attempts have been made to administer the following groups of medications: β-blockers, opioid receptor antagonists, angiotensin convertase inhibitors and angiotensin receptor antagonists. Other methods include replacing classic antipsychotic drugs with clozapine. There are also reports of a reduced severity of polydipsia with hyponatremia after introducing risperidone and olanzapine. Preventing episodes of water intoxication in patients with psychogenic polydipsia requires the monitoring of their body weight and a suitable reduction of fluid intake by them.

Results: Mentally ill patients, especially those with chronic schizophrenia, should be monitored for psychogenic polydipsia and the concomitant hyponatremia.

Association of fronto-temporal function with cognitive ability in schizophrenia

Deficits in neuropsychological performance are common in schizophrenia, but their relationship with the fronto-temporal functional abnormalities associated with this condition remains unclear. We explored the relationship between neuropsychological performance as measured using the Brief Assessment of Cognition in Schizophrenia (BACS) and the Social Cognition Screening Questionnaire theory of mind (ToM) subscale and fronto-temporal function in 23 patients with schizophrenia and 23 age- and gender-matched healthy controls (HCs), using 52-channel near-infrared spectroscopy (NIRS). Regional hemodynamic changes were significantly smaller in the schizophrenia group than in the HCs group in the ventro-lateral prefrontal cortex and the anterior part of the temporal cortex (VLPFC/aTC) and dorso-lateral prefrontal cortex and frontopolar cortex (DLPFC/FPC) regions. To dissect the effect of variance in BACS cognitive domains from the relationship between ToM function and fronto-temporal function, we performed additional partial correlation analyses between ToM and NIRS data, using BACS composite score as a control variable. The correlation between ToM and NIRS data remained significant only in the DLPFC/FPC region. This finding is important to models of recovery, as it suggests that intervention programs focusing on enhancing fronto-temporal function may have a greater impact on social and occupational outcomes than traditional rehabilitation programs focusing on neuropsychological performance.

Primary cerebral and cerebellar astrocytes display differential sensitivity to extracellular sodium with significant effects on apoptosis

Central pontine myelinolysis is one of the idiopathic or iatrogenic brain dysfunction, and the most common cause is excessively rapid correction of chronic hyponatraemia. While myelin disruption is the main pathology, as the diagnostic name indicates, a previous study has reported that astrocyte death precedes the destruction of the myelin sheath after the rapid correction of chronic low Na(+) levels, and interestingly, certain brain regions (cerebral cortex, hippocampus, etc.) are specifically damaged but not cerebellum. Here, using primary astrocyte cultures derived from rat cerebral cortex and cerebellum, we examined how extracellular Na(+) alterations affect astrocyte death and whether the response is different between the two populations of astrocytes. Twice the amount of extracellular [Na(+) ] and voltage-gated Na(+) channel opening induced substantial apoptosis in both populations of astrocytes, while, in contrast, one half [Na(+) ] prevented apoptosis in cerebellar astrocytes, in which the Na(+) -Ca(2+) exchanger, NCX2, was highly expressed but not in cerebral astrocytes. Strikingly, the rapid correction of chronic one half [Na(+) ] exposure significantly increased apoptosis in cerebellar astrocytes but not in cerebral astrocytes. These results indicate that extracellular [Na(+) ] affects astrocyte apoptosis, and the response to alterations in [Na(+) ] is dependent on the brain region from which the astrocyte is derived.