Correlations between executive function, decision-making and impulsivity are disrupted in schizophrenia versus controls

Tobacco use and impulsivity in people with mental illness: A systematic review

BACKGROUND AND OBJECTIVES

Impulsivity is a risk factor for the development and maintenance of tobacco use, especially among individuals with comorbid mental illness, but the nature of this relationship is poorly understood. We systematically examined evidence for the relationship between impulsivity and tobacco use in people with psychiatric disorders.

METHODS

Following PRISMA guidelines, original peer-reviewed articles published from database inception to July 2024 were searched for using PubMed, Google Scholar, ProQuest, Ovid, and PsycINFO.

RESULTS

Of 1192 articles identified, 16 met the inclusion criteria. There was consistent evidence of a positive relationship between tobacco use and impulsivity in schizophrenia (SZ), major depressive disorder (MDD) and bipolar disorder (BD). However, the majority of studies were cross-sectional studies, preventing causal inferences.

DISCUSSION AND CONCLUSIONS

Tobacco smoking is robustly associated with impulsivity in people with SZ, MDD, and BD, although causal conclusions cannot be drawn due to methodological limitations of the current literature. Future prospective and experimental studies are needed to ascertain whether impulsivity is a risk factor for smoking, how tobacco use affects impulsivity, and whether impulsivity may be a treatment target for smoking cessation.

SCIENTIFIC SIGNIFICANCE

To our knowledge, this article is the first comprehensive review of literature, specifically examining the relationship of tobacco smoking and impulsivity among individuals with psychiatric disorders. By highlighting this understudied intersection, our findings provide novel insights into the relationship between smoking behaviors and impulsivity in individuals with mental illness, contributing to more effective treatment strategies and emphasizing the need for tailored interventions to address these co-morbidities.

The comparison of decision-making in ambiguous situations and galvanic skin responses as somatic markers in patients with posterior cortex epilepsy and mesial temporal lobe epilepsy with hippocampal sclerosis

INTRODUCTION

Decision-making behaviors of patients with mesial temporal lobe epilepsy (MTLE) is a subject that has been studied frequently. However, determining the neuropsychological profiles of patients with different types of epilepsy is also important. Our main purpose was to examine the decision-making behaviors of patients with posterior cortex epilepsy (PCE) through the assumptions of somatic marker hypothesis (SMH) and to compare their performances with those of a MTLE group and a control group.

METHOD

Participants comprised of 13 patients with PCE (mean age 30.92 ± 9.99 years); 14 patients with MTLE with hippocampal sclerosis (MTLE-HS) (mean age 25.53 ± 7.40 years) and 15 controls (mean age 24.60 ± 8.45 years). Decision-making performances were assessed with the Iowa gambling test (IGT) and anticipatory skin responses before each choice were recorded. A comprehensive neuropsychological test battery was also given to all participants in order to examine the relationship of decision-making with other cognitive functions.

RESULTS

Anticipatory responses before choosing from disadvantageous decks were significantly larger than choosing from advantageous decks in the PCE group (p = 0.00). No significant difference was found between the PCE and control group's total net scores. IGT total net scores was significantly correlated with Stroop test interference time (p = 0.03).

CONCLUSION

The study reveals that cognitive impairments of patients with PCE are not limited to brain's posterior areas' functions, and provides evidence for the current paradigm which understands epilepsy as a network disorder.

Cumulative Genetic Score of DRD2 Polymorphisms Is Associated with Impulsivity and Masked Semantic Priming

Individual differences in the magnitude of semantic priming effects are associated with executive functions (EF). Striatal dopamine has been shown to be associated with EF as well as impulsivity and could therefore be associated with differences in the magnitude of semantic priming. We investigated n = 155 individuals in an unmasked as well as in a masked semantic priming paradigm. We additionally assessed self-reported impulsivity and a cumulative genetic score (CGS) comprising six polymorphisms that have been found to be functionally relevant for the expression of the DRD2 gene. We found a significantly negative association between the DRD2 CGS and reaction time priming in the masked semantic priming paradigm. In addition, the DRD2 CGS was positively associated with self-reported impulsivity. Our findings complement previous research by showing a role of the DRD2 gene for masked semantic priming. Therefore, the investigation of genes within the dopamine system might improve our understanding of the genetic basis of impulsivity and semantic processing. Thus, the DRD2 CGS is of interest for clinical as well as experimental psychological research.

Inflexible eye fixation pattern in schizophrenia affecting decision-making on daily life

Patients with schizophrenia have difficulties in real life due to impairment in ability to make decisions. The purpose of this study was to elucidate the relationship between impaired decision-making processes with real life stimuli and abnormal eye gaze patterns in patients with schizophrenia. Each of 23 patients with schizophrenia and 23 healthy controls performed an apparel purchase decision task including the influencing factors such as preference, fit, and price, during which the eye gaze was traced. Fixation time and fixation time ratio on areas of interest, which were set for participant faces and clothing, were compared between the two groups. Compared with controls, patients made purchase decisions at a higher rate and showed significantly shorter fixation time on clothing in the preference, fit, and price phases and on faces in the purchase phase. Fixation time ratio of face over clothing did not change over purchase decisions in patients, whereas controls showed significantly higher fixation time ratio in not-to-buy decisions than in to-buy decisions. These results suggest that aberrant decision-making behaviors in patients with schizophrenia are closely related to inflexible visual information gathering patterns because they apportion the same amount of attention to objects regardless of purchase intention.

Increased temporal discounting after chronic stress in CHL1-deficient mice is reversed by 5-HT2C agonist Ro 60-0175

Schizophrenia is a neurodevelopmental disorder in which impaired decision-making and goal-directed behaviors are core features. One of the genes associated with schizophrenia is the Close Homolog of L1 (CHL1); CHL1-deficient mice are considered a model of schizophrenia-like deficits, including sensorimotor gating, interval timing and spatial memory impairments. Here we investigated temporal discounting in CHL1-deficient (KO) mice and their wild-type littermates. Although no discounting differences were found under baseline conditions, CHL1-KO mice showed increased impulsive choice following chronic unpredictable stress (fewer % larger-later choices, and reduced area under the discounting curve). Stressed CHL1-KO mice also showed decreased neuronal activation (number of cFos positive neurons) in the discounting task in the prelimbic cortex and dorsal striatum, areas thought to be part of executive and temporal processing circuits. Impulsive choice alterations were reversed by the 5-HT2C agonist Ro 60-0175. Our results provide evidence for a gene x environment, double-hit model of stress-related decision-making impairments, and identify CHL1-deficient mice as a mouse model for these deficits in regard to schizophrenia-like phenotypes.

Addiction science: Uncovering neurobiological complexity

Until very recently addiction-research was limited by existing tools and strategies that were inadequate for studying the inherent complexity at each of the different phenomenological levels. However, powerful new tools (e.g., optogenetics and designer drug receptors) and high throughput protocols are starting to give researchers the potential to systematically interrogate "all" genes, epigenetic marks, and neuronal circuits. These advances, combined with imaging technologies (both for preclinical and clinical studies) and a paradigm shift toward open access have spurred an unlimited growth of datasets transforming the way we investigate the neurobiology of substance use disorders (SUD) and the factors that modulate risk and resilience. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.

Pathways to similar executive impairment: comparison of schizophrenia patients and healthy aging individuals

Executive impairment is prominent in schizophrenia, in conditions such as Parkinson's disease and dementia and in healthy aging. Identifying processes that critically constrain executive function can advance investigation of their biological basis and treatment planning. Recent findings that elderly healthy individuals showed similar impairment on conditional exclusion task as schizophrenia patients raised the question whether similar processes are impaired. To test this we compared 56 schizophrenia patients, 57 elderly and 77 young healthy individuals on three executive tests: conditional exclusion, abstraction and inhibition and tests of working memory and psychomotor speed. Schizophrenia patients performed worse than elderly healthy on abstraction, inhibition and verbal working memory. They were similarly impaired on Penn Conditional Exclusion Test (PCET) outcome measures but differed in performance characteristics. Schizophrenia patients needed relatively more trials to learn the first PCET category than the second or the third. This correlated with other cognitive impairments, particularly in working memory. Elderly healthy individuals found it most difficult to learn the last category. The two groups showed different error patterns. We propose that schizophrenia patients have particular difficulty in early (probabilistic) learning ("what to do") while aging individuals have selective impairment in executive integration. These constitute distinct targets for customized treatment in the two conditions.