Lower Vitamin C Levels Are Associated With Less Improvement in Negative Symptoms in Initially Antipsychotic-Naïve Patients With First-Episode Psychosis.

Low levels of vitamin C have been observed in patients with schizophrenia and psychosis, and vitamin C may affect the dopaminergic system. Likewise, antipsychotic medication modulates striatal dopamine D2 receptors. We measured vitamin C levels in 52 patients with first-episode psychoses (24 females, age 23.1 ± 5.2 years) and 57 matched HCs (20 females, age 22.7 ± 4.3 years) before and after 6 weeks where patients received aripiprazole monotherapy (mean dose 10.4 mg ± 4.8 mg). At baseline, patients displayed lower levels of vitamin C (57.4 ± 25.9 µM) than controls (72.7 ± 21.4 µM) (t = 3.4, P = .001). Baseline symptoms and vitamin C levels were not correlated. Higher baseline vitamin C levels were associated with more improvement in negative symptoms (n = 39, R2 = 0.20, F = 8.2, P = .007), but not with age, sex, or p-aripiprazole. Because negative symptoms are generally considered challenging to alleviate, a potential adjunctive effect of vitamin C on treatment response should be tested in future randomized clinical trials.

Treatment response after 6 and 26 weeks is related to baseline glutamate and GABA levels in antipsychotic-naïve patients with psychosis.

BACKGROUND: Poor response to dopaminergic antipsychotics constitutes a major challenge in the treatment of psychotic disorders and markers for non-response during first-episode are warranted. Previous studies have found increased levels of glutamate and γ-aminobutyric acid (GABA) in non-responding first-episode patients compared to responders, but it is unknown if non-responders can be identified using reference levels from healthy controls (HCs). METHODS: Thirty-nine antipsychotic-naïve patients with first-episode psychosis and 36 matched HCs underwent repeated assessments with the Positive and Negative Syndrome Scale and 3T magnetic resonance spectroscopy. Glutamate scaled to total creatine (/Cr) was measured in the anterior cingulate cortex (ACC) and left thalamus, and levels of GABA/Cr were measured in ACC. After 6 weeks, we re-examined 32 patients on aripiprazole monotherapy and 35 HCs, and after 26 weeks we re-examined 30 patients on naturalistic antipsychotic treatment and 32 HCs. The Andreasen criteria defined non-response. RESULTS: Before treatment, thalamic glutamate/Cr was higher in the whole group of patients but levels normalized after treatment. ACC levels of glutamate/Cr and GABA/Cr were lower at all assessments and unaffected by treatment. When compared with HCs, non-responders at week 6 (19 patients) and week 26 (16 patients) had higher baseline glutamate/Cr in the thalamus. Moreover, non-responders at 26 weeks had lower baseline GABA/Cr in ACC. Baseline levels in responders and HCs did not differ. CONCLUSION: Glutamatergic and GABAergic abnormalities in antipsychotic-naïve patients appear driven by non-responders to antipsychotic treatment. If replicated, normative reference levels for glutamate and GABA may aid estimation of clinical prognosis in first-episode psychosis patients.

Glucagon-like peptide-1 receptor agonists for antipsychotic-associated cardio-metabolic risk factors: A systematic review and individual participant data meta-analysis.

AIMS: To evaluate if glucagon-like peptide-1 receptor agonists (GLP-1RAs) reduce antipsychotic-associated body weight gain in patients with schizophrenia, when compared to controls. MATERIALS AND METHODS: We systematically searched PubMed/EMBASE/PsycINFO/Cochrane using the search terms '(antipsychotic and GLP-1RA)'. Individual participant data from studies randomizing patients to GLP-1RA or control were meta-analysed. The primary outcome was difference in body weight between GLP-1RA and control; secondary outcomes included cardio-metabolic variables and adverse drug reactions (ADRs). Multiple linear regression was conducted including sex, age, psychosis severity, metabolic variable, ADRs, and GLP-1RA agent. RESULTS: Three studies (exenatide once-weekly = 2; liraglutide once-daily = 1) provided participant-level data (n = 164, age = 40.0 ± 11.1 years, body weight = 105.8 ± 20.8 kg). After 16.2 ± 4.0 weeks of treatment, body weight loss was 3.71 kg (95% CI = 2.44-4.99 kg) greater for GLP-1RA versus control (p < 0.001), number-needed-to-treat ≥5% body weight loss = 3.8 (95% CI = 2.6-7.2). Waist circumference, body mass index, HbA1c, fasting glucose and visceral adiposity were each significantly lower with GLP-1RA. Sex, age, psychosis severity, nausea, any ADR, and GLP-1RA agent did not significantly impact outcomes. Body weight loss with GLP-1RAs was greater for clozapine/olanzapine-treated patients (n = 141) than other antipsychotics (n = 27) (4.70 kg, 95% CI = 3.13-6.27 vs. 1.5 kg, 95% CI = -1.47-4.47) (p < 0.001). Nausea was more common with GLP-1RAs than control (53.6% vs. 27.5%, p = 0.002, number-needed-to-harm = 3.8). CONCLUSION: GLP-1RAs are effective and tolerable for antipsychotic-associated body weight gain, particularly clozapine/olanzapine-treated patients. With few included patients, further studies are required before making routine use recommendations for GLP-1RAs.

Effect of GLP-1 receptor agonist treatment on body weight in obese antipsychotic-treated patients with schizophrenia: a randomized, placebo-controlled trial.

AIMS: Schizophrenia is associated with cardiovascular co-morbidity and a reduced life-expectancy of up to 20 years. Antipsychotics are dopamine D2 receptor antagonists and are the standard of medical care in schizophrenia, but the drugs are associated with severe metabolic side effects such as obesity and diabetes. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are registered for treatment of both obesity and type 2 diabetes. We investigated metabolic effects of the GLP-1RA, exenatide once-weekly, in non-diabetic, antipsychotic-treated, obese patients with schizophrenia. MATERIAL AND METHODS: Antipsychotic-treated, obese, non-diabetic, schizophrenia spectrum patients were randomized to double-blinded adjunctive treatment with once-weekly subcutaneous exenatide (n = 23) or placebo (n = 22) injections for 3 months. The primary outcome was loss of body weight after treatment and repeated measures analysis of variance was used as statistical analysis. RESULTS: Between March 2013 and June 2015, 40 patients completed the trial. At baseline, mean body weight was 118.3 ± 16.0 kg in the exenatide group and 111.7 ± 18.0 kg in the placebo group, with no group differences ( P = .23). The exenatide and placebo groups experienced significant ( P = .004), however similar ( P = .98), weight losses of 2.24 ± 3.3 and 2.23 ± 4.4 kg, respectively, after 3 months of treatment. CONCLUSIONS: Treatment with exenatide once-weekly did not promote weight loss in obese, antipsychotic-treated patients with schizophrenia compared to placebo. Our results could suggest that the body weight-lowering effect of GLP-1RAs involves dopaminergic signaling, but blockade of other receptor systems may also play a role. Nevertheless, anti-obesity regimens effective in the general population may not be readily implemented in antipsychotic-treated patients with schizophrenia.

Impaired GABAergic inhibition in the prefrontal cortex of early postnatal phencyclidine (PCP)-treated rats.

A compromised γ-aminobutyric acid (GABA)ergic system is hypothesized to be part of the underlying pathophysiology of schizophrenia. N-methyl-D-aspartate (NMDA) receptor hypofunction during neurodevelopment is proposed to disrupt maturation of interneurons causing an impaired GABAergic transmission in adulthood. The present study examines prefrontal GABAergic transmission in adult rats administered with the NMDA receptor channel blocker, phencyclidine (PCP), for 3 days during the second postnatal week. Whole-cell patch-clamp recordings from pyramidal cells in PCP-treated rats showed a 22% reduction in the frequency of miniature inhibitory postsynaptic currents in layer II/III, but not in layer V pyramidal neurons of the prefrontal cortex. Furthermore, early postnatal PCP treatment caused insensitivity toward effects of the GABA transporter 1 (GAT-1) inhibitor, 1,2,5,6-tetrahydro-1-[2-[[(diphenyl-methylene)amino]oxy]ethyl]-3-pyridinecarboxylic acid, and also diminished currents passed by δ-subunit-containing GABAA receptors in layer II/III pyramidal neurons. The observed impairments in GABAergic function are compatible with the alteration of GABAergic markers as well as cognitive dysfunction observed in early postnatal PCP-treated rats and support the hypothesis that PCP administration during neurodevelopment affects the functionality of interneurons in later life.

Differential expression of parvalbumin in neonatal phencyclidine-treated rats and socially isolated rats.

Decreased parvalbumin expression is a hallmark of the pathophysiology of schizophrenia and has been associated with abnormal cognitive processing and decreased network specificity. It is not known whether this decrease is due to reduced expression of the parvalbumin protein or degeneration of parvalbumin-positive interneurons (PV(+) interneurons). In this study, we examined PV(+) expression in two rat models of cognitive dysfunction in schizophrenia: the environmental social isolation (SI) and pharmacological neonatal phencyclidine (neoPCP) models. Using a stereological method, the optical fractionator, we counted neurons, PV(+) interneurons, and glial cells in the medial prefrontal cortex (mPFC) and hippocampus (HPC). In addition, we quantified the mRNA level of parvalbumin in the mPFC. There was a statistically significant reduction in the number of PV(+) interneurons (p = 0.021) and glial cells (p = 0.024) in the mPFC of neonatal phencyclidine rats, but not in SI rats. We observed no alterations in the total number of neurons, hippocampal PV(+) interneurons, parvalbumin mRNA expression or volume of the mPFC or HPC in the two models. Thus, as the total number of neurons remains unchanged following phencyclidine (PCP) treatment, we suggest that the decreased number of counted PV(+) interneurons represents a reduced parvalbumin protein expression below immunohistochemical detection limit rather than a true cell loss. Furthermore, these results indicate that the effect of neonatal PCP treatment is not limited to neuronal populations.

Heritability of Cerebral Blood Flow and the Correlation to Schizophrenia Spectrum Disorders: A Pseudo-continuous Arterial Spin Labeling Twin Study.

Whether aberrant cerebral blood flow (CBF) in schizophrenia is affected by genetic influences, and consequently a potential marker for genetic susceptibility, is unknown. Our aims were to determine the heritability of CBF in thalamic, frontal, and striatal areas, and to ascertain if associations with disease were under genetic influence. Monozygotic (MZ) twin pairs concordant (n = 2) or discordant (n = 20) for schizophrenia spectrum disorders (ICD-10 F2x.x), matched on sex and age with dizygotic (DZ; n = 20) and healthy control pairs (MZ: n = 27; DZ: n = 18; total: n = 181 individuals), were recruited via the National Danish Twin Register. CBF in thalamus, frontal lobes, and putamen was measured with pseudo-continuous arterial spin labeling on a 3 T magnetic resonance scanner. Twin statistics were performed with structural equation modeling. CBF in the frontal lobes was heritable (h2 = 0.44, 95% CI [0.22-0.60]) but not correlated to disease. CBF correlated to schizophrenia spectrum disorders in the left thalamus (r = 0.17, [0.03-0.31]; P = 0.02), as well as in the left putamen (r = 0.19, [0.05-0.32]; P = 0.007) and the right putamen (r = 0.18, [0.03-0.32]; P = 0.02). When restricting the sample to schizophrenia (F20.x) only, shared genetic influences between CBF in the left putamen and schizophrenia liability (phenotypic correlation = 0.44, [0.28-0.58], P < 0.001) were found. Our results provide heritability estimates of CBF in the frontal lobes, and we find CBF in thalamus and putamen to be altered in schizophrenia spectrum disorders. Furthermore, shared genetic factors influence schizophrenia liability and striatal perfusion. Specifically, higher perfusion in the left putamen may constitute a marker of genetic susceptibility for schizophrenia.

Bone Status in Obese, Non-diabetic, Antipsychotic-Treated Patients, and Effects of the Glucagon-Like Peptide-1 Receptor Agonist Exenatide on Bone Turnover Markers and Bone Mineral Density.

Background: Low bone mineral density (BMD) may constitute an underestimated comorbidity in schizophrenia patients undergoing long-term antipsychotic treatment. Glucagon-like peptide 1 (GLP-1) receptor agonists are antidiabetic drugs, which may also affect bone turnover. Methods: In planned secondary analyses of a 3 months, double-blind, randomized, placebo-controlled trial (n = 45), we explored effects of the GLP-1 receptor agonist exenatide 2 mg once-weekly (n = 23), or placebo (n = 22) on bone turnover markers (BTMs) and BMD in chronic, obese, antipsychotic-treated patients with schizophrenia spectrum disorder. Baseline BTMs were compared to sex- and age-adjusted reference values from a Danish population cohort, and T- and Z-scores were calculated for BMD. Results: In women (n = 24), all baseline BTM measurements of procollagen type I N-terminal propeptide (PINP) and C-terminal cross-linking telopeptide of type I collagen (CTX) were within reference values. In men (n = 21), 5% displayed lower PINP and 14% displayed lower CTX. One patient displayed BMD Z-score < -2, and 23% of patients (17% of women and 29% of men) displayed -2.5 < T-scores < -1 indicating osteopenia, but none had osteoporosis. After treatment, PINP decreased at trend level significance (P = 0.05), and body mass index BMD increased for L2-L4 (P = 0.016). No changes in bone markers were significant after correction for mean prolactin levels. Conclusions: Sex- and age-adjusted measures of bone status in chronic, obese, antipsychotic-treated patients appeared comparable to the reference population. Subtle changes in bone markers during 3 months exenatide treatment may suggest beneficial effects of GLP-1 receptor agonists on bone status in antipsychotic-treated patients, and further studies should consider the potential influence of prolactin.

Multiple measures of HPA axis function in ultra high risk and first-episode schizophrenia patients.

INTRODUCTION: Abnormalities within hypothalamus-pituitary-adrenal (HPA) axis might interact with other neurobiological systems to enhance the risk of psychosis. Most of the neurodevelopmental and HPA axis changes occur in adolescence; this is also the period when prodromal and psychotic symptoms occur for the first time. More knowledge about how various stress components interact can advance understanding of the link between psychosis and the HPA axis. METHOD: We examined 41 ultra high-risk (UHR) patients and 40 antipsychotic-naïve first-episode schizophrenia (FES) patients and compared them with 47 matched controls. The Perceived Stress Scale and the Recent Life Events Questionnaire were used to assess the stress levels. Day-time saliva samples were taken to measure cortisol. The pituitary gland volume was measured manually on the structural MRI using stereology. RESULTS: Only the UHR patients, had a higher cortisol increase just after awakening (p = 0.009) compared to healthy controls. In UHR patients, we found a negative correlation between cortisol increase after awakening and symptom severity (p = 0.008). Pituitary gland volume and diurnal cortisol were not significantly different among the three groups. There was no correlation between pituitary gland volume, perceived stress/recent life events and any of the cortisol measures or symptoms. CONCLUSION: Symptom severity during the very early phase of illness (UHR) seems to be associated with altered cortisol increase. Longitudinal studies in UHR patients would be useful to examine how stress levels affect the course of the illness.

Postprandial prolactin suppression appears absent in antipsychotic-treated male patients.

INTRODUCTION: Hyperprolactinemia is a common side-effect of antipsychotic treatment. Antipsychotics and hyperprolactinemia are both considered risk factors of metabolic disturbances and diabetes. Investigations on prolactin response to meal ingestion in antipsychotic-treated patients are missing. MATERIAL AND METHODS: In a case-control design, 49 antipsychotic-treated, clinically stable, non-diabetic, schizophrenia spectrum male patients were compared with 93 healthy male controls by age (33.1, SD 7.4 vs. 32.9, SD 6.6 years), body mass index (26.2, SD 4.6 vs. 26.1, SD 3.9 kg/m(2)) and waist circumference (96.4, SD 13.0 vs. 96.7, SD 11.9 cm). Serum-prolactin was measured in the morning and 90 min after ingestion of a standardized liquid meal (2268 kJ). RESULTS: Fasting prolactin levels varied considerably, and mean fasting prolactin levels did not significantly differ between patients and controls (12.33, SD 11.58 vs. 10.06, SD 8.67 ng/ml, p = 0.623). In the controls, postprandial serum prolactin was significantly reduced (Δ -2.53, SD 9.75 ng/ml, p = 0.016). In antipsychotic-treated patients postprandial serum prolactin tended to increase (Δ 2.62, SD 10.96 ng/ml, p = 0.081). Analyses of subgroups based on the prolactinogenic liability of their antipsychotic treatment indicated 22 to 65% higher postprandial prolactin levels with high and intermediate prolactinogenic antipsychotics. DISCUSSION: A physiological postprandial suppression of serum prolactin appears absent in antipsychotic-treated males. Marked variability in fasting prolactin levels may reflect individual variations in the diurnal cycle. Uniform acquisition procedures accounting for diurnal variation and food intake may enhance reliability of prolactin levels in antipsychotic-treated male patients.

Treatment of antipsychotic-associated obesity with a GLP-1 receptor agonist--protocol for an investigator-initiated prospective, randomised, placebo-controlled, double-blinded intervention study: the TAO study protocol.

INTRODUCTION: Antipsychotic medication is widely associated with dysmetabolism including obesity and type 2 diabetes, cardiovascular-related diseases and early death. Obesity is considered the single most important risk factor for cardiovascular morbidity and mortality. Interventions against antipsychotic-associated obesity are limited and insufficient. Glucagon-like peptide-1 (GLP-1) receptor agonists are approved for the treatment of type 2 diabetes, but their bodyweight-lowering effects have also been recognised in patients with non-diabetes. The primary endpoint of this trial is weight loss after 3 months of treatment with a GLP-1 receptor agonist (exenatide once weekly) in patients with non-diabetic schizophrenia with antipsychotic-associated obesity. Secondary endpoints include physiological and metabolic measurements, various psychopathological and cognitive measures, and structural and functional brain MRI. METHODS AND ANALYSIS: 40 obese patients with schizophrenia or schizoaffective disorder treated with antipsychotic drugs will be randomised to subcutaneous injection of exenatide once weekly (2 mg) or placebo for 3 months, adjunctive to their antipsychotic treatment. ETHICS AND DISSEMINATION: The trial has been approved by the Danish Health and Medicines Authority, the National Committee on Health Research Ethics and the Danish Data Protection Agency. Trial participation presupposes theoral and written patient informed consent. An external, independent monitoring committee (Good Clinical Practice Unit at Copenhagen University Hospital) will monitor the study according to the GCP Guidelines. Trial data, including positive, negative and inconclusive results, will be presented at national and international scientific meetings and conferences. Papers will be submitted to peer-reviewed journals. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01794429; National Committee on Health Research Ethics project number: 36378; EudraCT nr: 2012-005404-17; The Danish Data Protection Agency project number: RHP-2012-027.

A schizophrenia rat model induced by early postnatal phencyclidine treatment and characterized by Magnetic Resonance Imaging.

Better animal models are needed to aid the development of new medications to alleviate the cognitive deficits associated with schizophrenia. Growing evidence suggests neurodevelopmental insults and disturbances in NMDA receptor (NMDAR) signaling to be involved in the schizophrenia etiology. Acute administration of phencyclidine (PCP) induces schizophrenia-like symptoms in healthy volunteers and exacerbates symptoms in patients with schizophrenia. In this study, pharmacological Magnetic Resonance Imaging (phMRI) was used to evaluate if rats treated with 20mg/kg PCP on postnatal days 7, 9, and 11 (neoPCP), compared to saline (neoVeh), were hypersensitive to acute PCP administration in adulthood (acutePCP). Intravenous administration of 0.5mg/kg acutePCP produced robust and sustained relative cerebral blood volume (rCBV) increase in discrete frontal, neocortical, hippocampal, thalamic, and limbic brain structures in both neoPCP:acutePCP and neoVeh:acutePCP rats compared to acute saline treatment (Vehicle control group). AcutePCP injection significantly increased the rCBV response in the medial prefrontal cortex and nucleus accumbens compared to the Vehicle control group, without distinguishing neoPCP and neoVeh animals. However, at late time points (25-33min post acutePCP injection), neoPCP animals showed significantly higher rCBV values compared to the Vehicle control group, suggesting an altered sensitivity toward NMDAR blockade in adult rats subjected to this neurodevelopmental procedure. In combination with the observed cognitive deficits revealed in this animal model, the present findings indicate that altered NMDAR signaling might underlie the symptomatic changes seen in schizophrenia, adding to the construct and face validity of this model.