Philippe Conus

N-acetyl cysteine as a glutathione precursor for schizophrenia--a double-blind, randomized, placebo-controlled trial.

BACKGROUND Brain glutathione levels are decreased in schizophrenia, a disorder that often is chronic and refractory to treatment. N-acetyl cysteine (NAC) increases brain glutathione in rodents. This study was conducted to evaluate the safety and effectiveness of oral NAC (1 g orally twice daily [b.i.d.]) as an add-on to maintenance medication for the treatment of chronic schizophrenia over a 24-week period. METHODS A randomized, multicenter, double-blind, placebo-controlled study. The primary readout was change from baseline on the Positive and Negative Symptoms Scale (PANSS) and its components. Secondary readouts included the Clinical Global Impression (CGI) Severity and Improvement scales, as well as general functioning and extrapyramidal rating scales. Changes following a 4-week treatment discontinuation were evaluated. One hundred forty people with chronic schizophrenia on maintenance antipsychotic medication were randomized; 84 completed treatment. RESULTS Intent-to-treat analysis revealed that subjects treated with NAC improved more than placebo-treated subjects over the study period in PANSS total [-5.97 (-10.44, -1.51), p = .009], PANSS negative [mean difference -1.83 (95% confidence interval: -3.33, -.32), p = .018], and PANSS general [-2.79 (-5.38, -.20), p = .035], CGI-Severity (CGI-S) [-.26 (-.44, -.08), p = .004], and CGI-Improvement (CGI-I) [-.22 (-.41, -.03), p = .025] scores. No significant change on the PANSS positive subscale was seen. N-acetyl cysteine treatment also was associated with an improvement in akathisia (p = .022). Effect sizes at end point were consistent with moderate benefits. CONCLUSIONS These data suggest that adjunctive NAC has potential as a safe and moderately effective augmentation strategy for chronic schizophrenia.

The impact of substance use disorders on clinical outcome in 643 patients with first-episode psychosis.

Objective:  Studies investigating the impact of comorbid substance use disorders (SUD) in psychosis have tended to focus on cross‐sectional data, with few studies examining the effects of substance use course on clinical outcome. The main aim of the present study was to assess the impact of baseline SUD and course of SUD on remission of positive symptoms.

Glutathione Precursor, N-Acetyl-Cysteine, Improves Mismatch Negativity in Schizophrenia Patients

In schizophrenia patients, glutathione dysregulation at the gene, protein and functional levels, leads to N-methyl-D-aspartate (NMDA) receptor hypofunction. These patients also exhibit deficits in auditory sensory processing that manifests as impaired mismatch negativity (MMN), which is an auditory evoked potential (AEP) component related to NMDA receptor function. N-acetyl-cysteine (NAC), a glutathione precursor, was administered to patients to determine whether increased levels of brain glutathione would improve MMN and by extension NMDA function. A randomized, double-blind, cross-over protocol was conducted, entailing the administration of NAC (2g/day) for 60 days and then placebo for another 60 days (or vice versa). 128-channel AEPs were recorded during a frequency oddball discrimination task at protocol onset, at the point of cross-over, and at the end of the study. At the onset of the protocol, the MMN of patients was significantly impaired compared to sex- and age- matched healthy controls (p=0.003), without any evidence of concomitant P300 component deficits. Treatment with NAC significantly improved MMN generation compared with placebo (p=0.025) without any measurable effects on the P300 component. MMN improvement was observed in the absence of robust changes in assessments of clinical severity, though the latter was observed in a larger and more prolonged clinical study. This pattern suggests that MMN enhancement may precede changes to indices of clinical severity, highlighting the possible utility AEPs as a biomarker of treatment efficacy. The improvement of this functional marker may indicate an important pathway towards new therapeutic strategies that target glutathione dysregulation in schizophrenia.

Impaired glutathione synthesis in schizophrenia: Convergent genetic and functional evidence

Schizophrenia is a complex multifactorial brain disorder with a genetic component. Convergent evidence has implicated oxidative stress and glutathione (GSH) deficits in the pathogenesis of this disease. The aim of the present study was to test whether schizophrenia is associated with a deficit of GSH synthesis. Cultured skin fibroblasts from schizophrenia patients and control subjects were challenged with oxidative stress, and parameters of the rate-limiting enzyme for the GSH synthesis, the glutamate cysteine ligase (GCL), were measured. Stressed cells of patients had a 26% (P = 0.002) decreased GCL activity as compared with controls. This reduction correlated with a 29% (P < 0.001) decreased protein expression of the catalytic GCL subunit (GCLC). Genetic analysis of a trinucleotide repeat (TNR) polymorphism in the GCLC gene showed a significant association with schizophrenia in two independent case-control studies. The most common TNR genotype 7/7 was more frequent in controls [odds ratio (OR) = 0.6, P = 0.003], whereas the rarest TNR genotype 8/8 was three times more frequent in patients (OR = 3.0, P = 0.007). Moreover, subjects with disease-associated genotypes had lower GCLC protein expression (P = 0.017), GCL activity (P = 0.037), and GSH contents (P = 0.004) than subjects with genotypes that were more frequent in controls. Taken together, the study provides genetic and functional evidence that an impaired capacity to synthesize GSH under conditions of oxidative stress is a vulnerability factor for schizophrenia.

Does stage of illness impact treatment response in bipolar disorder? Empirical treatment data and their implication for the staging model and early intervention

OBJECTIVE The staging model suggests that early stages of bipolar disorder respond better to treatments and have a more favourable prognosis. This study aims to provide empirical support for the model, and the allied construct of early intervention. METHODS Pooled data from mania, depression, and maintenance studies of olanzapine were analyzed. Individuals were categorized as having had 0, 1-5, 6-10, or >10 prior episodes of illness, and data were analyzed across these groups. RESULTS Response rates for the mania and maintenance studies ranged from 52-69% and 10-50%, respectively, for individuals with 1-5 previous episodes, and from 29-59% and 11-40% for individuals with >5 previous episodes. These rates were significantly higher for the 1-5 group on most measures of response with up to a twofold increase in the chance of responding for those with fewer previous episodes. For the depression studies, response rates were significantly higher for the 1-5 group for two measures only. In the maintenance studies, the chance of relapse to either mania or depression was reduced by 40-60% for those who had experienced 1-5 episodes or 6-10 episodes compared to the >10 episode group, respectively. This trend was statistically significant only for relapse into mania for the 1-5 episode group (p=0.005). CONCLUSION Those individuals at the earliest stages of illness consistently had a more favourable response to treatment. This is consistent with the staging model and underscores the need to support a policy of early intervention.

Impact of duration of untreated psychosis on pre-treatment, baseline, and outcome characteristics in an epidemiological first-episode psychosis cohort

INTRODUCTION To assess the impact of duration of untreated psychosis (DUP) on baseline and 18-month follow-up characteristics controlling for relevant confounders in an epidemiological first-episode psychosis (FEP) cohort. METHOD The Early Psychosis Prevention and Intervention Centre (EPPIC) in Australia admitted 786 FEP patients from January 1998 to December 2000. Data were collected from medical files using a standardized questionnaire. Data from 636 patients were analyzed. RESULTS Median DUP was 8.7 weeks. Longer DUP was associated with worse premorbid functioning (p<0.001), higher rate of schizophrenia-spectrum disorders (p<0.001), and younger age at onset of psychosis (p=0.004). Longer DUP was not associated with baseline variables but with a lower rate of remission of positive symptoms (p<0.001) and employment/occupation (p<0.001), a higher rate of persistent substance use (p=0.015), worse illness severity (p<0.001) and global functioning (p<0.001) at follow-up after controlling for relevant confounders, explaining approximately 5% of variance of remission of positive symptoms (p<0.001) in the total sample and 3% in schizophrenia-spectrum disorders excluding bipolar I disorder (p=0.002). Outcome was significantly worse when DUP exceeded 1-3 months. CONCLUSION Avoiding pitfalls of non-epidemiological studies, DUP appears to be a modest independent predictor of prognosis in the medium-term. Results support the need for assertive early detection strategies.

Stage managing bipolar disorder

Clinical staging is widespread in medicine – it informs prognosis, clinical course, and treatment, and assists individualized care. Staging places an individual on a probabilistic continuum of increasing potential disease severity, ranging from clinically at‐risk or latency stage through first threshold episode of illness or recurrence, and, finally, to late or end‐stage disease. The aim of the present paper was to examine and update the evidence regarding staging in bipolar disorder, and how this might inform targeted and individualized intervention approaches.

First-episode mania: a neglected priority for early intervention

Objective: While first-episode (FE) psychosis has become an important field of research, FE affective psychoses, and mania in particular, have been relatively neglected. This paper summarizes current knowledge about FE mania and explores the potential for early intervention. Method: The main computerized psychiatric literature databases were accessed. Results: When functional as well as symptomatic variables are considered, the outcome of mania is not as good as was formerly believed, a characteristic which is already present from the first episode. Various factors (lower socio-economic status, younger age at onset of illness, poor adherence to treatment, presence of comorbidity) have been identified as possible predictors of poor outcome. The prognostic value of the presence of psychotic symptoms and their congruence to mood, as well as the diagnostic subgroup, is less well established. This literature review also reveals striking similarities between manic and schizophreniform first episodes. Poor functional outcome in a significant proportion of patients following the first episode, high risk of suicide, high prevalence of comorbid diagnoses, worse outcome with a younger age at onset and with longer delay until treatment is initiated, and finally early presence of neuro-anatomical changes, are observed in both syndromes. Conclusions: This pattern justifies the development of early intervention strategies for FE manic patients and supports more exploratory research to identify prodromal symptoms, which might ultimately lead to even earlier focus on preventive interventions.

The 16p11.2 locus modulates brain structures common to autism, schizophrenia and obesity

Anatomical structures and mechanisms linking genes to neuropsychiatric disorders are not deciphered. Reciprocal copy number variants at the 16p11.2 BP4-BP5 locus offer a unique opportunity to study the intermediate phenotypes in carriers at high risk for autism spectrum disorder (ASD) or schizophrenia (SZ). We investigated the variation in brain anatomy in 16p11.2 deletion and duplication carriers. Beyond gene dosage effects on global brain metrics, we show that the number of genomic copies negatively correlated to the gray matter volume and white matter tissue properties in cortico-subcortical regions implicated in reward, language and social cognition. Despite the near absence of ASD or SZ diagnoses in our 16p11.2 cohort, the pattern of brain anatomy changes in carriers spatially overlaps with the well-established structural abnormalities in ASD and SZ. Using measures of peripheral mRNA levels, we confirm our genomic copy number findings. This combined molecular, neuroimaging and clinical approach, applied to larger datasets, will help interpret the relative contributions of genes to neuropsychiatric conditions by measuring their effect on local brain anatomy.

The proximal prodrome to first episode mania – a new target for early intervention

OBJECTIVE Affective psychoses and bipolar disorders have been neglected in the development of early intervention strategies. This paper aims to gather current knowledge on the early phase of bipolar disorders in order to define new targets for early intervention. METHODS Literature review based on the main computerized databases (MEDLINE, PUBMED and PSYCHLIT) and hand search of relevant literature. RESULTS Based on current knowledge, it is likely that an approach aiming at the identification of impending first-episode mania is the most realistic and manageable strategy to promote earlier treatment. During the period preceding the onset of the first manic episode, patients go through a prodromal phase marked by the presence of mood fluctuation, sleep disturbance, and other symptoms such as irritability, anger, or functional impairment. Additionally, various risk factors and markers of vulnerability to bipolar disorders have been identified. CONCLUSIONS In the few months preceding first-episode mania, patients go through a prodrome phase (proximal prodrome) that could become an important target for early intervention. However, considering the low specificity of the symptoms observed during this phase, criteria defining high-risk profiles to first-episode mania should also include certain risk factors or markers of vulnerability. While more research is needed in high-risk groups (e.g., bipolar offspring), retrospective studies conducted in first-episode mania cohorts could provide valuable information about this critical phase of the illness.