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Introduction Impaired illness awareness or the inability to recognize that one has a dependence on nicotine may be a major barrier to seeking cessation treatment. To better understand the role of impaired illness awareness on treatment-seeking behavior and clinical outcomes, we developed and examined the psychometric properties of a novel scale measuring illness awareness in individuals with dependence on nicotine. Aims and Methods We developed the Nicotine Use Awareness and Insight Scale (NAS), a 7-item self-report measure to assess the theoretical construct of illness awareness in individuals with dependence on nicotine (www.illnessawarenessscales.com). Data from participants 18 years of age or older were collected via a web-based survey company, Dynata. Participants with moderate dependence on nicotine were included, defined by a score of four or more on the Fagerström Test for Cigarette Dependence (FTCD) or the FTCD adapted for electronic cigarettes (eFTCD). Results A total of 100 participants (mean [SD] age = 49.1 [16.1] years, 52% women) that met the inclusion criteria for either FTCD (n = 50) or eFTCD (n = 50) were included. The NAS demonstrated good convergent (r = .74, p < .001) and discriminant validity (r = .03, p = .786). It also demonstrated good internal consistency (Cronbach’s alpha = 0.78) and one-month test-retest reliability (intra-class correlation = 0.86). An exploratory factor analysis yielded the retention of two components. Conclusions The NAS is a novel scale to asses illness awareness in individuals with dependence on nicotine. This study provides initial support for the psychometric validity and reliability of NAS. Implications The NAS may be used in research and clinical practice to evaluate the impact of impaired illness awareness on treatment-seeking behavior and clinical outcomes.

Treatment-resistant schizophrenia (TRS) has been suggested to involve glutamatergic dysfunction. Glutathione (GSH), a dominant antioxidant, is known to be involved in glutamatergic neurotransmission. To date, no study has examined GSH levels in patients with TRS. The aim of this study was to examine GSH levels in the dorsal anterior cingulate cortex (dACC) of patients with TRS. Patients with schizophrenia were categorized into 3 groups with respect to their antipsychotic response: (1) clozapine (CLZ) nonresponders, (2) CLZ responders, and (3) first-line responders (FLR). GSH and glutamine + glutamate (Glx) levels were measured using 3T proton magnetic resonance spectroscopy. Firstly, dACC GSH levels were compared among the patient groups and healthy controls (HCs). Further, relationships between GSH and Glx levels were compared between the groups and GSH levels were explored stratifying the patient groups based on the glutamate-cysteine ligase catalytic (GCLC) subunit polymorphism. There was no difference in GSH levels between the groups. FLR showed a more negative relationship between GSH and Glx levels in the dACC compared to HCs. There were no effects of GCLC genotype on the GSH levels. However, CLZ responders had a higher ratio of high-risk GCLC genotype compared to CLZ nonresponders. This study demonstrated different relationships between GSH and Glx in the dACC between groups. In addition, the results suggest a potential link between CLZ response and GCLC genotype. However, it still remains unclear how these differences are related to the underlying pathophysiology of schizophrenia subtypes or the mechanisms of action of CLZ.

Background Proton Magnetic Resonance Spectroscopy (1H-MRS) studies indicate that altered brain glutamate signalling contributes to the pathophysiology of schizophrenia and treatment response. However it is unclear whether clinical and demographic factors affect glutamate levels in the brain. Here we aim to determine the effects of age, antipsychotic medication, symptom severity and duration of illness on levels of glutamatergic metabolites and creatine, in a large multicentre dataset of patients with schizophrenia and healthy volunteers. Methods Authors of 1H-MRS studies in schizophrenia were contacted between January 2014 and August 2017 and asked to provide individual glutamate, Glx, glutamine and creatine values alongside demographic and clinical data. Forty-five 1H-MRS studies contributed data to the multicentre dataset, and data was available from 1194 healthy volunteers and 1526 patients with schizophrenia and those at high risk of developing psychosis. Results Age was associated with reduced glutamate levels in the medial frontal cortex, but the effect of aging was not accelerated in patients compared to healthy volunteers. Higher glutamate and Glx in the medial frontal and temporal lobes were associated with more severe symptoms, whereas Glx in subcortical regions, specifically the thalamus and striatum, did not relate to symptom severity. In the medial frontal cortex and striatum, exposure to antipsychotic medication was associated with lower levels of glutamatergic metabolites. Duration of illness was not associated with glutamatergic metabolites. Lastly, creatine in the medial frontal cortex and thalamus increased with age. Discussion These data suggest that future 1H-MRS studies should control for the effects of age, symptom severity, and antipsychotic medication exposure. Caution is needed when using creatine as a reference to scale metabolites.

Given that approximately one-third of patients with schizophrenia do not respond to antipsychotics, different neurobiological bases may underlie treatment resistance in schizophrenia. Previous studies showed that treatment response is associated with both frontostriatal connectivity and glutamatergic neurometabolite levels in the caudate in patients with schizophrenia, which leads to the hypothesis that the relationship between them may be altered, specifically in patients with treatment-resistant schizophrenia (TRS). Employing analyses of covariance and subsequent partial correlation analyses, we compared the relationship between glutamate+glutamine (Glx) levels in the caudate and fractional anisotropy (FA) values in the tract between the dorsolateral prefrontal cortex and caudate in 19 patients with TRS, 20 patients responsive to first-line antipsychotics (FL-Resp), and 19 healthy controls (HCs). TRS was defined by severe positive symptomatology despite first-line antipsychotic treatment. Patients with TRS had lower FA values in the bilateral frontostriatal tracts than patients with FL-Resp and HCs (P < .001), while no group differences were found in caudate Glx levels. There was a significant frontostriatal FA value-by-group interaction on caudate Glx levels (F = 7.37, P = .009). Frontostriatal FA values positively correlated with caudate Glx levels in HCs (r = −.55, P = .028), while they were negatively associated with caudate Glx levels in the TRS group (r = .53, P = .043). Furthermore, in the FL-Resp group, frontostriatal FA values did not significantly correlated with caudate Glx levels. The altered relationship between white matter integrity and the glutamate system in the frontostriatal circuit in the TRS group may reflect the pathophysiology underlying treatment response/resistance in schizophrenia.

Kynurenic acid (KYNA) is an endogenous antagonist of N-methyl-D-aspartate and α7 nicotinic acetylcholine receptors that is derived from astrocytes as part of the kynurenine pathway of tryptophan degradation. Evidence suggests that abnormal KYNA levels are involved in the pathophysiology of schizophrenia. However, this has never been assessed through a meta-analysis. A literature search was conducted through Ovid using Embase, Medline, and PsycINFO databases (last search: December 2016) with the search terms: (kynuren* or KYNA) and (schizophreni* or psychosis). English language studies measuring KYNA levels using any method in patients with schizophrenia and healthy controls (HCs) were identified. Standardized mean differences (SMDs) were calculated to determine differences in KYNA levels between groups. Subgroup analyses were separately performed for nonoverlapping participant samples, KYNA measurement techniques, and KYNA sample source. The influences of patients’ age, antipsychotic status (%medicated), and sex (%male) on study SMDs were assessed through a meta-regression. Thirteen studies were deemed eligible for inclusion in the meta-analysis. In the main analysis, KYNA levels were elevated in the patient group. Subgroup analyses demonstrated that KYNA levels were increased in nonoverlapping participant samples, and centrally (cerebrospinal fluid and brain tissue) but not peripherally. Patients’ age, %medicated, and %male were each positively associated with study SMDs. Overall, KYNA levels are increased in patients with schizophrenia, specifically within the central nervous system. An improved understanding of KYNA in patients with schizophrenia may contribute to the development of novel diagnostic approaches and therapeutic strategies.

Glial disturbances are highly implicated in the pathophysiology of schizophrenia and may be linked with glutamatergic dysregulation. Myo-inositol (mI), a putative marker of glial cells, and choline (Cho), representative of membrane turnover, are both present in larger concentrations within glial cells than in neurons, and their elevation is often interpreted to reflect glial activation. Proton magnetic resonance spectroscopy ((1)H-MRS) allows for the evaluation of mI, Cho, glutamate, glutamate + glutamine (Glx), and N-acetylaspartate (NAA). A collective investigation of these measures in antipsychotic-naive patients experiencing their first nonaffective episode of psychosis (FEP) can improve the understanding of glial dysfunction and its implications in the early stages of schizophrenia. 3-Tesla (1)H-MRS (echo time = 35 ms) was performed in 60 antipsychotic-naive patients with FEP and 60 age- and sex-matched healthy controls. mI, Cho, glutamate, Glx, and NAA were estimated using LCModel and corrected for cerebrospinal fluid composition within the voxel. mI, Cho, and glutamate were elevated in the FEP group. After correction for multiple comparisons, mI positively correlated with grandiosity. The relationships between mI and glutamate, and Cho and glutamate, were more positive in the FEP group. These findings are suggestive of glial activation in the absence of neuronal loss and may thereby provide support for the presence of a neuroinflammatory process within the early stages of schizophrenia. Dysregulation of glial function might result in the disruption of glutamatergic neurotransmission, which may influence positive symptomatology in patients with FEP.

Impact of dose reduction of atypical antipsychotics on cognitive function has not been investigated in stable patients with schizophrenia. In this open-label, 28-week, randomized controlled trial, stable patients with schizophrenia treated with risperidone or olanzapine were randomly assigned to the reduction group (dose reduced by 50% in 4 weeks and then maintained) or maintenance group (dose kept constant). Assessments at baseline and week 28 included the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), Positive and Negative Syndrome Scale (PANSS), and Drug-Induced Extrapyramidal Symptoms Scale (DIEPSS). Sixty-one patients were enrolled; 2 of 31 (6.5%) and 5 of 30 (16.7%) patients prematurely withdrew from the study in the reduction and maintenance groups, respectively. While no significant differences in change in the PANSS total score were observed between the 2 groups, the reduction group showed significantly greater improvements in the RBANS and DIEPSS total scores compared with the maintenance group (mean ± SD, +7.0±7.1 vs −0.1±8.0, P < .001; −0.9±1.7 vs +0.1±1.2, P = .010, respectively). This 6-month pilot study suggests that risperidone or olanzapine dose reduction of 50% can improve cognitive function for stable patients with schizophrenia. Due to the open-label design, small sample size, and short study duration, however, there is a need to confirm the finding through double-blind, larger scale trials with longer follow-up periods. Moreover, potential risks of relapse following antipsychotic dose reduction should be thoroughly investigated in longer term studies.

Background: Current literature suggests that the pathology of schizophrenia (SCZ) has developmental origins based on mounting evidence showing genetic abnormalities and prenatal factors contributing to the early onset of the illness. Nonetheless, there are progressive neurodegenerative processes in this illness that cannot be solely explicated by the neurodevelopmental theory of SCZ. In addition, numerous animal studies showed that antipsychotics elicit neuroprotective effects by lowering beta-amyloid (Aβ) levels.

Background: Studies using proton magnetic resonance spectroscopy (1H-MRS) have reported altered neurometabolite levels in patients with schizophrenia. However, results are inconsistent and confounded by the influence of antipsychotic (AP) administration. Thus, the aim of the present study was to examine neurometabolite levels in AP-naive/free patients with schizophrenia through a meta-analysis. Methods: A literature search was conducted using Embase, Medline, and PsycINFO to identify studies that compared neurometabolite levels in AP-naive/free patients with schizophrenia to healthy controls (last search: August 2016). Eight neurometabolites (glutamate, glutamine, glutamate + glutamine, N-acetylaspartate [NAA], choline, creatine, myo-inositol, and γ-aminobutyric acid) and 7 regions of interest (ROI; medial prefrontal cortex, dorsolateral prefrontal cortex, frontal white matter, occipital lobe, basal ganglia, hippocampus/medial temporal lobe, and thalamus) were examined. Standardized mean differences (SMDs) were calculated to assess neurometabolite-level differences between groups. Results: Twenty-two studies (N = 1142) were included in the analysis. The results showed lower thalamic NAA levels in the patient group (SMD = −0.56, P = .0005). No differences were identified for other neurometabolites. Conclusion: This study extends previously reported findings demonstrating a decrease of NAA levels in patients with chronic schizophrenia. On the other hand, previously reported alterations of glutamatergic neurometabolite levels were not replicated. Further studies are required to detect the influence of AP on these neurometabolites levels.

Background: Dysregulations of the major inhibitory and excitatory amino neurotransmitter systems of γ-aminobutyric acid and glutamate, respectively, have been described in patients with schizophrenia. However, it is unclear whether these abnormalities are present in subjects at ultra-high risk for psychosis. Methods: Twenty-three antipsychotic naive subjects at ultra-high risk and 24 healthy control subjects, matched for age, sex, handedness, cigarette smoking, and parental education, underwent proton magnetic resonance spectroscopy scans in the dorsal caudate bilaterally and the medial prefrontal cortex at 3T. Levels of γ-aminobutyric acid and of the combined resonance of glutamate and glutamine (Glx) were obtained using the standard J-editing technique and expressed as peak area ratios relative to the synchronously acquired unsuppressed voxel water signal. Results: Higher levels of γ-aminobutyric acid ( P

Antipsychotic drugs produce unpleasant subjective experiences, which have been associated with high levels of dopamine D2 receptor occupancy. Aripiprazole is a partial agonist antipsychotic, which is hypothesized to produce a different subjective experience profile compared to standard D2 antagonist antipsychotics. The aim of this study was to compare the effect of D2 occupancy produced by a partial agonist antipsychotic (aripiprazole) to that of antagonist antipsychotics (risperidone or olanzapine) on the subjective well-being of patients. Subjective well-being was measured using the Subjective Well-being under Neuroleptics Scale (SWN) and was related to dopamine D2 receptor occupancy using [11C]raclopride PET. Patients that were switched to aripiprazole showed improvement in their subjective well-being from 79.80 (S.D.=16.08) to 89.90 (S.D.=15.33), an effect that was sustained for 6 months. This sustained improvement was observed despite very high levels of DA D2 occupancy (82–99%), in contrast to the effects of antagonist antipsychotics on subjective well-being., peer-reviewed