Atypical antipsychotics and polydipsia: a cause or a treatment?

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.

Diabetes insipidus related to sedation in the intensive care unit: A review of the literature

PURPOSE

To identify cases of diabetes insipidus (DI) related to sedation in the ICU to determine which medications pose the greatest risk and understand patterns of presentation.

MATERIALS AND METHODS

We searched PubMed, Embase, Scopus, Google Scholar, and Web of Science. Search terms included "polyuria," "diabetes insipidus," "hypnotics and sedatives," "sedation," as well as individual medications. Case reports or series involving DI or polyuria related to sedation in the ICU were identified.

RESULTS

We identified 21 cases of diabetes insipidus or polyuria in the ICU attributed to a sedative. Dexmedetomidine was implicated in 42.9% of cases, followed by sevoflurane (33.3%) and ketamine (23.8%). Sevoflurane was implicated in all 7 cases in which it was used (100%; 95% CI 59.0%, 100.0%), dexmedetomidine in 9 of 11 cases (81.8%; 95% CI 48.2, 97.7), and ketamine in 5 of 9 cases (55.6%; 95% CI 21.2%, 86.3%).

CONCLUSIONS

Awareness of the potential for sedatives to cause DI may lead to greater identification with swifter medication discontinuation and subsequent resolution of DI.

Primary polydipsia: Update

In primary polydipsia pathologically high levels of water intake physiologically lower arginine vasopressin (AVP) secretion, and in this way mirror the secondary polydipsia in diabetes insipidus in which pathologically low levels of AVP (or renal responsiveness to AVP) physiologically increase water intake. Primary polydipsia covers several disorders whose clinical features and significance, risk factors, pathophysiology and treatment are reviewed here. While groupings may appear somewhat arbitrary, they are associated with distinct alterations in physiologic parameters of water balance. The polydipsia is typically unrelated to homeostatic regulation of water intake, but instead reflects non-homeostatic influences. Recent technological advances, summarized here, have disentangled functional neurocircuits underlying both homeostatic and non-homeostatic physiologic influences, which provides an opportunity to better define the mechanisms of the disorders. We summarize this recent literature, highlighting hypothalamic circuitry that appears most clearly positioned to contribute to primary polydipsia. The life-threatening water imbalance in psychotic disorders is caused by an anterior hippocampal induced stress-diathesis that can be reproduced in animal models, and involves phylogenetically preserved pathways that appear likely to include one or more of these circuits. Ongoing translational neuroscience studies in these animal models may potentially localize reversible pathological changes which contribute to both the water imbalance and psychotic disorder.

Relationship between polydipsia and antipsychotics: A systematic review of clinical studies and case reports

OBJECTIVE

This systematic review aimed to elucidate the relationship between polydipsia and antipsychotics.

METHODS

We systematically searched MEDLINE, Embase, and PsycINFO, and included clinical studies and case reports on polydipsia induced or improved by antipsychotics.

RESULTS

We identified 61 articles: 1 double-blind randomized controlled trial (RCT), 4 single-arm trials, 1 cross-sectional study, 3 case series, and 52 case reports. The double-blind RCT demonstrated no significant difference in improvement in polydipsia between olanzapine and haloperidol. Two single-arm trials showed that polydipsia improved during clozapine treatment, whereas the other 2 showed that risperidone did not improve polydipsia. The cross-sectional study showed the prevalence of hyponatremia with first-generation antipsychotics (FGAs: 26.1%) and second-generation antipsychotics (SGAs: 4.9%). Two case series reported that clozapine improved polydipsia; the other one indicated that patients with polydipsia who were treated with FGAs had schizophrenia (70.4%) and mental retardation (25.9%). Of 90 cases in the case reports, 67 (75.3%) were diagnosed with schizophrenia. Of 83 cases in which antipsychotic treatment started before the onset of polydipsia, 75 (90.3%) received FGAs, particularly haloperidol (n = 24, 28.9%), and 11 (13.3%) received risperidone. Among 40 cases in which polydipsia was improved following antipsychotic treatment, 36 (90.0%) received SGAs, primarily clozapine (n = 14, 35.0%).

CONCLUSIONS

Although the causal relationship between polydipsia and antipsychotics remains unclear because of the paucity of high-quality studies, antipsychotics with high affinity to dopamine D₂ receptors may be associated with an increased risk of polydipsia while clozapine may be effective for treating polydipsia.

Psychogenic Polydipsia Complicated to Hyponatremia Induced Seizure in Schizophrenia: A Case Report from Nepal

Psychogenic polydipsia is one of the common cooccurrences with Schizophrenia and if not addressed can lead to fatal consequences. There are some evidences for pharmacological management of this condition but nonpharmacological management starting from psycho-education to behavioural modification therapy involving family members can be a very effective strategy. We report a case from Nepal where psychogenic polydipsia was complicated to hyponatremia and lead to seizure episodes. We emphasize on asking a routine question about polydipsia in every patient of Schizophrenia in clinics.

Cannabidiol improves behavioural and neurochemical deficits in adult female offspring of the maternal immune activation (poly I:C) model of neurodevelopmental disorders

Cognitive impairment is a major source of disability in schizophrenia and current antipsychotic drugs (APDs) have minimal efficacy for this symptom domain. Cannabidiol (CBD), the major non-intoxicating component of Cannabis sativa L., exhibits antipsychotic and neuroprotective properties. We recently reported the effects of CBD on cognition in male offspring of a maternal immune activation (polyinosinic-polycytidilic acid (poly I:C)) model relevant to the aetiology of schizophrenia; however, the effects of CBD treatment in females are unknown. Sex differences are observed in the onset of schizophrenia symptoms and response to APD treatment. Furthermore, the endogenous cannabinoid system, a direct target of CBD, is sexually dimorphic in humans and rodents. Therefore, the present work aimed to assess the therapeutic impact of CBD treatment on behaviour and neurochemical signalling markers in female poly I:C offspring. Time-mated pregnant Sprague-Dawley rats (n = 16) were administered poly I:C (4 mg/kg; i.v.) or saline (control) on gestational day 15. From postnatal day 56, female offspring received CBD (10 mg/kg, i.p.) or vehicle treatment for approximately 3 weeks. Following 2 weeks of CBD treatment, offspring underwent behavioural testing, including the novel object recognition, rewarded alternation T-maze and social interaction tests to assess recognition memory, working memory and sociability, respectively. After 3 weeks of CBD treatment, the prefrontal cortex (PFC) and hippocampus (HPC) were collected to assess effects on endocannabinoid, glutamatergic and gamma-aminobutyric acid (GABA) signalling markers. CBD attenuated poly I:C-induced deficits in recognition memory, social interaction and glutamatergic N-methyl-d-aspartate receptor (NMDAR) binding in the PFC of poly I:C offspring. Working memory performance was similar between treatment groups. CBD also increased glutamate decarboxylase 67, the rate-limiting enzyme that converts glutamate to GABA, and parvalbumin protein levels in the HPC. In contrast to the CBD treatment effects observed in poly I:C offspring, CBD administration to control rats reduced social interaction, cannabinoid CB1 receptor and NMDAR binding density in the PFC, suggesting that CBD administration to healthy rats may have negative consequences on social behaviour and brain maturation in adulthood. Overall, the findings of this study support the therapeutic benefits of CBD on recognition memory and sociability in female poly I:C offspring, and provide insight into the neurochemical changes that may underlie the therapeutic benefits of CBD in the poly I:C model.

Antipsychotics and severe hyponatremia: A Swedish population-based case-control study

BACKGROUND

Antipsychotics have been claimed to cause hyponatremia. The risk associated with individual antipsychotics, or groups (first-generation [FGAs] or second-generation [SGAs] antipsychotics), is not well-documented. The objective of this study was to investigate the association between antipsychotics and hospitalization due to hyponatremia.

METHODS

The general Swedish population was the base of this register-based case-control study. Comparisons were made between patients hospitalized with a principal diagnosis of hyponatremia (n = 14,359) and matched controls (n = 57,383). Multivariable logistic regression adjusting for concomitant drugs, medical conditions, previous hospitalizations and socioeconomic factors was performed to investigate the association between hyponatremia and antipsychotic use. In addition newly initiated (≤90 days) or ongoing use was analysed separately.

RESULTS

Compared to controls, the adjusted OR (95%CI) for hospitalization due to hyponatremia was for any antipsychotic 1.67(1.5-1.86). Individuals on FGA were more likely to experience severe hyponatremia (2.12[1.83-2.46]) than those on any SGA (1.32[1.15-1.51]). No increased risks, neither as newly initiated nor ongoing therapy, were found for risperidone (0.86[0.56-1.31] and 0.83[0.67-1.02]) and aripiprazole (1.16[0.30-4.46] and 0.62[0.27-1.34]), respectively.

CONCLUSIONS

There was an association between antipsychotic therapy and hospitalization due to hyponatremia. The association was stronger for FGAs than SGAs. Risperidone was not associated with an increased risk.

The preclinical discovery and development of cariprazine for the treatment of schizophrenia

INTRODUCTION

Cariprazine is approved in the United States and Europe for the treatment of manic or mixed episodes associated with bipolar I disorder and for the treatment of schizophrenia in adult patients. It is typically administered orally once a day (a dose range 1.5 - 6 mg/day), does require titration, and may be given with or without food. It has a half-life of 2 - 4 days with an active metabolite that has a terminal half-life of 2 - 3 weeks. Areas covered: This review article focuses on the preclinical discovery of cariprazine providing details regarding its pharmacological, behavioral, and neurochemical mechanisms and its contribution to clinical therapeutic benefits. This article is based on the available literature with respect to the preclinical and clinical findings and product labels of cariprazine. Expert opinion: Cariprazine shows highest affinity toward D₃ receptors, followed by D₂, 5-HT_2B, and 5-HT_1A receptors. It also shows moderate affinity toward σ₁, 5-HT_2A, and histamine H₁ receptors. Long-term administration of cariprazine altered the abundance of dopamine, serotonin, and glutamate receptor subtypes in different brain regions. All these mechanisms of cariprazine may contribute toward its unique preclinical profile and its clinically observed benefits in the treatment of schizophrenia, bipolar mania, and possibly other psychiatric disorders.

Cariprazine Exhibits Anxiolytic and Dopamine D3 Receptor-Dependent Antidepressant Effects in the Chronic Stress Model

Background

Cariprazine, a D3-preferring dopamine D2/D3 receptor partial agonist, is a new antipsychotic drug recently approved in the United States for the treatment of schizophrenia and bipolar mania. We recently demonstrated that cariprazine also has significant antianhedonic-like effects in rats subjected to chronic stress; however, the exact mechanism of action for cariprazine's antidepressant-like properties is not known. Thus, in this study we examined whether the effects of cariprazine are mediated by dopamine D3 receptors.

Methods

Wild-type and D3-knockout mice were exposed to chronic unpredictable stress for up to 26 days, treated daily with vehicle, imipramine (20 mg/kg), aripiprazole (1 and 5 mg/kg), or cariprazine (0.03, 0.1, 0.2, and 0.4 mg/kg), and tested in behavioral assays measuring anhedonia and anxiety-like behaviors.

Results

Results showed that cariprazine significantly attenuated chronic unpredictable stress-induced anhedonic-like behavior in wild-type mice, demonstrating potent antidepressant-like effects comparable with aripiprazole and the tricyclic antidepressant imipramine. This antianhedonic-like effect of cariprazine was not observed in D3-knockout mice, suggesting that the cariprazine antidepressant-like activity is mediated by dopamine D3 receptors. Moreover, cariprazine significantly reduced drinking latency in the novelty-induced hypophagia test in wild-type mice, further confirming its antianhedonic-like effect and showing that it also has anxiolytic-like activity.

Conclusions

In combination with previous studies, these results suggest that cariprazine has a unique pharmacological profile and distinct dopamine D3 receptor-dependent mechanism of action that may be beneficial in the treatment of schizophrenia, bipolar disorder, and major depressive disorder.

Antipsychotic use is a risk factor for hyponatremia in patients with schizophrenia: a 15-year follow-up study

RATIONALE

Hyponatremia affects 10% of patients with chronic schizophrenia and can lead to severe consequences. However, the role of antipsychotics and other risk factors in hyponatremia occurrence has remained inconsistent.

OBJECTIVE

This study examined the association between antipsychotic use and hyponatremia occurrence in patients with schizophrenia.

METHODS

We utilized the National Health Insurance Research Database to follow 2051 patients with schizophrenia from 1998 to 2013. Among them, 137 (6.7%) developed hyponatremia. Sociodemographic characteristics, physical comorbidities, and psychiatric treatment experiences were compared between those who had hyponatremia and those who did not. A Cox proportional hazards model was used to examine the hazard ratios (HRs) of these characteristics.

RESULTS

In patients with hyponatremia, the mean age at first hyponatremia occurrence was 54.7 ± 13.9 years, an average of 9.5 ± 4.0 years after schizophrenia diagnosis, and 32.9% of them were off antipsychotics before hyponatremia occurrences. Age at schizophrenia diagnosis (HR = 1.1), low-income household (HR = 2.4), comorbidities (HR = 1.2), and psychiatric admissions (HR = 1.04) were associated with the risks of hyponatremia. Compared with no antipsychotic use, atypical (HR = 2.1) and typical antipsychotics (HR = 3.1) were associated with an elevated risk of hyponatremia, after adjustment for age, sex, and physical comorbidities. Carbamazepine use (HR = 2.9) was also a significant risk factor for hyponatremia (p < 0.05).

CONCLUSIONS

Antipsychotic use in patients with schizophrenia with polypharmacy should be monitored for hyponatremia occurrences. Clinicians should pay attention to the impact of poor living conditions on hyponatremia occurrence.

Atypical antipsychotic medications and hyponatremia in older adults: a population-based cohort study

BACKGROUND

A number of case reports have suggested a possible association between atypical antipsychotic medications and hyponatremia. Currently, there are no reliable estimates of hyponatremia risk from atypical antipsychotic drugs.

OBJECTIVE

The objective of this study was to examine the 30-day risk of hospitalization with hyponatremia in older adults dispensed an atypical antipsychotic drug relative to no antipsychotic use.

DESIGN

The design of this study was a retrospective, population-based cohort study.

SETTING

The setting of this study was in Ontario, Canada, from 2003 to 2012.

PATIENTS

Adults 65 years or older with an identified psychiatric condition who were newly dispensed risperidone, olanzapine, or quetiapine in the community setting compared to adults with similar indicators of baseline health who were not dispensed such a prescription.

MEASUREMENTS

The primary outcome was the 30-day risk of hospitalization with hyponatremia. The tracer outcome (an outcome that is not expected to be influenced by the study drugs) was the 30-day risk of hospitalization with bowel obstruction. These outcomes were assessed using hospital diagnosis codes.

METHODS

Using health administrative data, we applied a propensity score technique to match antipsychotic users 1:1 to non-users of antipsychotic drugs (58,008 patients in each group). We used conditional logistic regression to compare outcomes among the matched users and non-users.

RESULTS

A total of 104 baseline characteristics were well-balanced between the two matched groups. Atypical antipsychotic use compared to non-use was associated with an increased risk of hospitalization with hyponatremia within 30 days (86/58,008 (0.15 %) versus 53/58,008 (0.09 %); relative risk 1.62 (95 % confidence interval (CI) 1.15 to 2.29); absolute risk increase 0.06 % (95 % CI 0.02 to 0.10)). The limited number of events precluded some additional analyses to confirm if the association was robust. Atypical antipsychotic use compared to non-use was not associated with hospitalization with bowel obstruction within 30 days (55/58,008 (0.09 %) versus 44/58,008 (0.08 %); relative risk 1.25 (95 % CI 0.84 to 1.86)).

LIMITATIONS

We could only study older adults within our data sources.

CONCLUSIONS

In this study, the use of an atypical antipsychotic was associated with a modest but statistically significant increase in the 30-day risk of a hospitalization with hyponatremia. The association was less pronounced than that described with other psychotropic drugs.

Excessive drinking of fluids in children and adults on the autism spectrum: a brief report

Purpose

– Excessive drinking of fluids occurs across the autism spectrum but despite the detrimental and potentially hazardous consequences very few studies of this phenomenon have been published. Literature on the topic is sparse. The purpose of this paper is to explore the issues via a large on-line survey and a clinic sample. It is hoped this study will encourage further interest in and investigation including exploration of the links with the neurology underlying autistic conditions.

Design/methodology/approach

– Results were obtained via a large on-line survey of autistic individuals and parents and carers (n=637) and data from referrals to a single diagnostic assessment and diagnostic clinic.

Findings

– Of 634 respondents of the on-line survey 474 reported excessive drinking of fluids in severe form. Almost two-thirds stated that this started before the age of five years. Of the children and adults seen at the clinic approximately one-third had dunk fluids excessively in the past. The effects of gender, type of autism condition, intellectual disability, reported stress and associated conditions were examined as were the type of fluids drunk and rate of drinking. The response to having to wait for a drink and the occurrence of vomiting and diarrhoea were also examined.

Research limitations/implications

– This is a preliminary study but with a large sample size. Limitations lie in the sparse amount of literature on this topic as it affects autism and reliance on parental and self-reports from an on-line survey, the majority of whom responded to an appeal for participants for whom excessive drinking of fluids was an established problem. The clinic sample comprised children and adults who had not been referred for reasons connected to excessive drinking of fluids but for whom this was still a significant problem. A further limitation concerns the absence of data on sensory profiles. This would be worth including in any follow up.

Practical implications

– It is important to be aware of the implications of excessive drinking of fluids on the health and well-being of children and adults on the autism spectrum. As there are potentially lethal consequences associated with such behaviours it is essential that they are recognised, understood and responded to.

Social implications

– Excessive drinking of fluids has implications for the development of the child and far reaching consequences for physical and social well-being.

Originality/value

– This is an original paper that draws on the limited literature available but is primarily based on the results of a unique on-line survey and evaluation of a clinic sample.

Polydipsia, hyponatremia and rhabdomyolysis in schizophrenia: A case report

The prevalence of polydipsia among patients with schizophrenia is 6%-20%. Around 10%-20% of patients with polydipsia may develop hyponatremia and even complicated with rhabdomyolysis. Here we presented a 40-year-old man with schizophrenia, who had received paliperidone 15 mg/d for more than one year, and polydipsia was noted. In Jan, 2014, he developed hyponatremia (Na 113 mEq/L) with consciousness disturbance. After 3% NaCl (500 cc/d) intravenous supplement for three days, the hyponatremia was corrected, but rhabdomyolysis developed with a substantial elevation in the level of creatine kinase (CK) to 30505 U/L. After hydration, the CK level gradually decreased to 212 U/L. Both the hyponatremia itself and quick supplementation of NaCl can cause rhabdomyolysis. If rhabdomyolysis is not recognized, insufficient hydration or water restriction for polydipsia may further exacerbate the rhabdomyolysis with a lethal risk. In this case, we highlight the possible complication of rhabdomyolysis with polydipsia-induced hyponatremia. In addition to monitoring the serum sodium level, the monitoring of CK is also important; and switching of antipsychotic may improve the polydipsia.

A suspected case of olanzapine induced hyponatremia

Here we report a case of a 63-year-old male diagnosed with recurrent depressive disorder and current episode of severe depression with psychotic symptoms, developed hyponatremia soon after addition of olanzapine and increasing the dose of escitalopram. A possible causality association was established with olanzapine, and the possible etiological reasons of this clinically significant risk were discussed.

The amphetamine sensitization model of schizophrenia symptoms and its effect on schedule-induced polydipsia in the rat

RATIONALE

Amphetamine enhances dopamine (DA) transmission and induces psychotic states or exacerbates psychosis in at-risk individuals. Amphetamine sensitization of the DA system has been proposed as a rodent model of schizophrenia-like symptoms. In humans, excessive nonphysiologic drinking or primary polydipsia is significantly associated with a diagnosis of schizophrenia. In rodents, nonphysiologic drinking can be induced by intermittent presentation of food in the presence of a drinking spout to a hungry animal; this phenomenon is termed, "schedule-induced polydipsia" (SIP).

OBJECTIVE

This study aims to determine the effects of amphetamine sensitization on SIP.

METHODS

We injected rats with amphetamine (1.5 mg/kg) daily for 5 days. Following 4 weeks of withdrawal, animals were food restricted and exposed to the SIP protocol (noncontingent fixed-time 1-min food schedule) for daily 2-h sessions for 24 days.

RESULTS

Results showed that previously amphetamine-injected animals drank more in the SIP protocol and drank more than controls when the intermittent food presentation schedule was removed.

CONCLUSIONS

These findings suggest that hyperdopaminergia associated with schizophrenia may contribute to the development of polydipsia in this population. Whether animals that develop SIP have DA dysfunction or aberrant activity of other circuits that modulate DA activity has yet to be clearly defined.

Safety of long-term clozapine administration. Frequency of cardiomyopathy and hyponatraemia: two cross-sectional, naturalistic studies

BACKGROUND

The antipsychotic drug (APD) clozapine (CLZ) is under-prescribed because of concerns about its safety. We evaluated in separate protocols the frequency of cardiomyopathy and hyponatraemia, which are adverse drug effects, where few comparative studies are available.

METHODS

Cross-sectional studies in subjects treated for at least 3 consecutive months with the same drug were conducted. Cardiomyopathy: Patients undergoing treatment either with CLZ (n = 125) or with other typical or atypical APDs (n = 59) were examined by a cardiologist who also recorded echocardiograms and electrocardiograms in order to diagnose cardiomyopathy. Hyponatraemia: Fasting sodium levels were assessed in patients receiving any of the following treatments: CLZ (n = 88), other atypical APDs (n = 61), typical APDs (n = 23), typical + atypical APDs (n = 11), and other drugs/drug-free (n = 36).

RESULTS

Cardiomyopathy: No case of cardiomyopathy was detected. The frequency of abnormal ventricular ejection fraction (< 55%) was similar in both treatment groups (p = 1). Hyponatraemia: The frequency of hyponatraemia (percentage; 95% CI) was: CLZ (3.4%; -0.7, 7.1); other atypical APDs (4.9%; -0.5, 10.3); typical APDs (26.1%; 8.2, 44.0); typical + atypical APDs (9.1%; -7.8, 26.0); other drugs/drug-free (0%). None of the CLZ hyponatraemia subjects were on monotherapy.

CONCLUSIONS

Our results are at odds with previous studies of CLZ-associated cardiomyopathy. However, they must be compared to further cross-sectional or prospective studies because most published data come from either case reports or pharmacovigilance systems. The frequency of hyponatraemia during CLZ administration was similar to that observed with other atypical APDs, and it was significantly lower than that recorded with typical agents. These results, along with numerous case reports on the effects of CLZ in patients with polydipsia and water intoxication, point to a safe or even positive profile of CLZ on electrolytic regulation.

Acute kidney injury, sodium disorders, and hypercalcemia in the aging kidney: diagnostic and therapeutic management strategies in emergency medicine

This article summarizes the current literature regarding the structural and functional changes of the aging kidney and describes how these changes make the older patient more susceptible to acute kidney injury and fluid and electrolyte disorders. It discusses the clinical manifestations, evaluation, and management of hyponatremia and shows how the management of hypernatremia in geriatric patients involves addressing the underlying cause and safely correcting the hypernatremia. The current literature regarding evaluation and management of hypercalcemia in older patients is summarized. The management of severe hypercalcemia is discussed in detail. The evaluation and management of acute kidney injury is described.

Effects of naltrexone on food intake and body weight gain in olanzapine-treated rats

Blockade of opioidergic neurotransmission contributes to reduction in body weight. However, how such blockade affects body weight gain (BWG) attributed to second generation antipsychotic agents (SGAs) has not yet been established. Here we examined the effects of an opioid receptor antagonist, naltrexone (NTX), on food intake and BWG associated with an SGA, olanzapine (OL). Four groups of Wistar Han IGS rats were treated for 28 days with either OL (2 mg/kg twice daily, intraperitoneal (IP)), a combination of OL (2 mg/kg twice daily, IP) + extended-release NTX (50 mg/kg, one-time, intramuscular (IM)), extended-release NTX (50 mg/kg, one-time, IM) or vehicle and their food intake and body weight were measured daily for the first nine days and every other day thereafter. Food intake and BWG that were increased by OL were decreased by the added NTX while NTX alone had no significant effects on food intake or on BWG. Plasma leptin concentrations were significantly elevated in the three groups receiving pharmacological agents, but did not differ among each other, suggesting that changes in leptin secretion and/or clearance alone would not explain the food intake and the body weight findings. Our results extend prior reports on anorexigenic effects of opioid antagonists by demonstrating that such effects may generalize to food intake increases and BWG arising in the context of OL pharmacotherapy.

Central Diabetes Insipidus presenting with manic symptoms

Central Diabetes Insipidus mostly presents with polydipsia and polyuria but may also present with confusion, psychosis, seizure or coma. We present a case of Central Diabetes Insipidus presenting with manic symptoms. A 21 year old Indian male had Central Diabetes Insipidus, which was confirmed by water deprivation test. He presented to our hospital with full blown manic symptoms meeting the ICD 10 criteria. He was managed with intranasal Desmopressin, water restriction and Olanzapine. In contrary to routine psychiatric patients which may present with psychogenic polydipsia or Central Diabetes Insipidus patients presenting in delirium or psychosis, our case presents a unique example of Central Diabetes Insipidus presenting with manic symptoms. It hints about a relationship between a common pathway for Central Diabetes Insipidus and mood disorders which needs further research. Diencephalon has already been the focus of attention for several researchers but no concrete evidence is available yet.

Psychogenic polydipsia in bipolar affective disorder--a case report

Polydipsia is a less examined but prevalent condition in patients with psychiatric disorders. It is usually described in schizophrenia but is rarely reported in bipolar affective disorder (BPAD). It is important to recognize and treat this entity as it can lead to serious complications. One needs to be cautious in choosing the mood stabilizer while treating this condition. We report the successful treatment of a patient with BPAD and polydipsia on a combination of valproate and risperidone.

The effects of clozapine on quinpirole-induced non-regulatory drinking and prepulse inhibition disruption in rats

RATIONALE

The biological underpinnings of schizophrenic polydipsia are poorly understood.

OBJECTIVES

This study is aimed at fulfilling the requisites of an experimental model of this syndrome through the quinpirole (QNP) induction of non-regulatory drinking in rats.

METHODS

In a first experiment, clozapine (10 and 40 mg/kg p.o.) was substituted for haloperidol during the last 5 days of 10 days QNP (0.5 mg/kg i.p.) administration and water intake measured at 5 h. In a second experiment, animals treated with QNP alone or in combination with clozapine were assessed for water intake and prepulse inhibition (PPI). Expression of genes coding for the dopaminergic D2 receptor, as well as for the early genes BDNF (brain-derived neurotrophic factor) and c-Fos in prefrontal cortex, hippocampus, and striatum was also evaluated.

RESULTS

Clozapine prevented QNP-induced drinking at 10 and 40 mg/kg, but only at 40 mg/kg when it was substituted for haloperidol. In the second experiment, QNP-treated rats showed both non-regulatory drinking and PPI disruption. Both these effects were prevented by clozapine 40 mg/kg. QNP-reduced BDNF expression in the hippocampus and increased c-Fos in the prefrontal cortex. This effect was prevented by clozapine. Given by itself, clozapine reduced the expression of both D2 receptors and BDNF in the prefrontal cortex and striatum.

CONCLUSIONS

The present study lends further support to the hypothesis that non-regulatory drinking induced by QNP in rats is a robust and reliable pharmacological effect that might model psychotic polydipsia also in its sensitivity to clozapine.

Risperidone-induced polydipsia and polyphagia associated with galactorrhea, abdominal pain, and rapid weight gain in an adolescent Hispanic female

A 15-year-old Hispanic female was started on risperidone for new-onset psychosis. The patient responded well to the gradual dose increase but developed rapid weight gain secondary to polydipsia and polyphagia. She also began complaining of nipple discharge and griping abdominal pain on the left lower quadrant by the third week of treatment. Her prolactin level escalated to three times normal with a weight gain of 12 pounds in 16 days. Risperidone was switched to another antipsychotic. Her prolactin level then dropped to a normal level within 7 days and she lost 7 pounds in the next 2 weeks. Her abdominal pain, galactorrhea, polydipsia, and polyphagia subsided within the first few days of the cessation of risperdione.