[Negative symptoms in schizophrenia and substance-related disorders]

Negative symptoms in drug-naive patients with a first-episode psychosis (FEP)

INTRODUCTION

Negative symptoms are nuclear features of schizophrenia that may be present from the onset of the disease. In recent years, it has been described 2 subdomains of negative symptoms: experiential and expressive deficits. The aim of the study is to examine the relationship between negative symptoms and demographic and clinical variables in patients with first-episode psychosis. Also, to explore whether there are differences in the association among these variables and negative symptoms when divided into both subdomains.

MATERIAL AND METHODS

A cross-sectional study was performed in 160 patients (52 females and 108 males) with a diagnosis of a first episode psychosis. A questionnaire was administered to collect demographic and clinical variables.

RESULTS

A backward stepwise linear regressions analysis was performed in order to observe potential associations between demographic and clinical variables and the presence of negative symptoms. All three models are predicted by worse PSP score, a higher CDSS, a higher disorganized factor score and a lower excited factor score. A longer duration of untreated psychosis (DUP) is associated to a higher score in the experiential deficit subdomain only.

CONCLUSIONS

Our work highlights some clinical and phenomenological differences between experiential and expressive deficits. We think that taking into account both subdomains in future studies may lead to more accurate clinical assessment and interventions.

Immune Influencers in Action: Metabolites and Enzymes of the Tryptophan-Kynurenine Metabolic Pathway

The tryptophan (TRP)-kynurenine (KYN) metabolic pathway is a main player of TRP metabolism through which more than 95% of TRP is catabolized. The pathway is activated by acute and chronic immune responses leading to a wide range of illnesses including cancer, immune diseases, neurodegenerative diseases and psychiatric disorders. The presence of positive feedback loops facilitates amplifying the immune responses vice versa. The TRP-KYN pathway synthesizes multifarious metabolites including oxidants, antioxidants, neurotoxins, neuroprotectants and immunomodulators. The immunomodulators are known to facilitate the immune system towards a tolerogenic state, resulting in chronic low-grade inflammation (LGI) that is commonly present in obesity, poor nutrition, exposer to chemicals or allergens, prodromal stage of various illnesses and chronic diseases. KYN, kynurenic acid, xanthurenic acid and cinnabarinic acid are aryl hydrocarbon receptor ligands that serve as immunomodulators. Furthermore, TRP-KYN pathway enzymes are known to be activated by the stress hormone cortisol and inflammatory cytokines, and genotypic variants were observed to contribute to inflammation and thus various diseases. The tryptophan 2,3-dioxygenase, the indoleamine 2,3-dioxygenases and the kynurenine-3-monooxygenase are main enzymes in the pathway. This review article discusses the TRP-KYN pathway with special emphasis on its interaction with the immune system and the tolerogenic shift towards chronic LGI and overviews the major symptoms, pro- and anti-inflammatory cytokines and toxic and protective KYNs to explore the linkage between chronic LGI, KYNs, and major psychiatric disorders, including depressive disorder, bipolar disorder, substance use disorder, post-traumatic stress disorder, schizophrenia and autism spectrum disorder.

Negative symptoms in first-episode psychosis: Clinical correlates and 1-year follow-up outcomes in London Early Intervention Services

AIM

Negative symptoms (NS) have been associated with poor outcome and remain difficult to treat in patients with psychosis. This study examined the association of NS with clinical features at first presentation to mental health services for psychosis and with outcomes at 1-year follow-up.

METHODS

Clinical data were utilized from five London Early Intervention Services (EIS) included in the MiData audit database. The sample comprised 484 first-episode psychosis patients with complete Positive and Negative Syndrome Scale data at baseline and 1-year follow-up. Multiple imputation (N = 50) was conducted to account for missing follow-up data.

RESULTS

Baseline NS were associated with male gender (B = -1.63, P < .05), younger age at onset (B = -.15, P <. 05), a higher level of impairment on the Global Assessment of Functioning (disability) Scale at baseline (B = -.19, P <. 010), an absence of reported substance misuse prior to baseline assessment (B = -3.05, P <. 001) and unemployment at baseline (B = -.93, P <. 01). At 1-year follow-up, NS at presentation were associated with worse Global Assessment of Functioning Scale for symptom (B = -.28, P < .01) and disability (B = -.27, P <. 05) and with hospital admission (OR = 1.06, P < .01).

CONCLUSIONS

Negative symptoms at presentation to EIS were associated with worse functioning at entry and poorer outcomes 1 year later. Future research is required to better understand the aetiology and trajectories of NS in early psychosis and propose novel targeted interventions.