Longitudinal course of core cognitive domains in first-episode acute and transient psychotic disorders compared with schizophrenia.

Acute and transient psychotic disorder (ATPD) is characterized by acute onset of psychotic symptoms and early recovery. Contrastingly, schizophrenia (SZ) is a chronic mental disorder characterized by impaired functioning including a deficit in cognition. In SZ, the cognitive deficit is among the core symptoms, but in ATPDs, the existing evidence brings mixed results. Our primary aim was to compare three core cognitive domains (executive functioning/abstraction, speed of processing and working memory) of patients diagnosed with ATPD and SZ over a 12-month period. Moreover, we explored how these diagnostic subgroups differed in their clinical characteristics. We recruited 39 patients with a diagnosis of SZ and 31 with ATPD with schizophrenic symptoms. All patients completed clinical and neuropsychological assessments. At baseline, we used a one-way ANCOVA model with a group as the between-subjects factor. Mixed-model repeated-measures ANOVAs with time as the within-subjects factor and group as the between-subjects factor were run to test the overtime differences. At baseline, we did not find any differences in cognition - with sex, education and age as covariates - between ATPDs and SZ. After one year, all patients showed an improvement in all three domains, however, there were no significant overtime changes between ATPDs and SZ. Regarding clinical profiles, ATPDs demonstrated less severe psychopathology and better functioning compared to SZ both at baseline and after 12 months. The medication dosage differed at retest, but not at baseline between the groups. Our findings suggest clinical differences and a similar trajectory of cognitive performance between these diagnostic subgroups.

Inflammation and cognitive performance in first-episode schizophrenia spectrum disorders: The moderating effects of childhood trauma.

In this study, we aimed to determine whether childhood trauma moderated the relationship between inflammation and cognitive functioning in persons with first-episode schizophrenia spectrum disorders (SSDs). We included data from 92 individuals who participated in the nationwide Early-Stage Schizophrenia Outcome study. These individuals completed the Childhood Trauma Questionnaire, provided a fasting blood sample for high-sensitivity C-reactive protein analysis, and underwent extensive neuropsychological testing. The intervening effects of age, sex, education, smoking status, and body mass index were controlled. Results indicated that childhood trauma levels significantly moderated the relationship between inflammation and four cognitive domains: speed of processing, working memory, visual memory, and verbal memory. Inflammation also predicted verbal memory scores irrespective of childhood trauma levels or the covariates. Upon further exploration, the significant moderation effects appeared to be primarily driven by males. In conclusion, a history of childhood trauma may be an important determinant in evaluating how inflammation relates to the cognitive performance of people with first-episode SSDs, particularly in speed of processing, working memory, visual memory, and verbal memory. We recommend that future researchers examining the effect of inflammation on cognitive functioning in SSDs include trauma as a moderating variable in their models and further examine additional moderating effects of sex.

Cognitive flexibility in schizophrenia: A confirmatory factor analysis of neuropsychological measures.

Cognitive flexibility (CF) is the ability to adapt cognitive strategies according to the changing environment. The deficit in CF has often been linked to various neurological and psychiatric disorders including schizophrenia. However, the operationalization and assessment of CF have not been unified and the current research suggests that the available instruments measure different aspects of CF. The main objective of the present study was to compare three frequently used neuropsychological measures of CF-Wisconsin Card Sorting Test (WCST), Trail Making Test (TMT) and Stroop Color and Word Test (SCWT) in a population of patients (N = 220) with first-episode schizophrenia spectrum disorders in order to evaluate their convergent validity. The hypothesis of an underlying latent construct was tested via a confirmatory factor analysis. We used a one-factor CF model with scores from WCST, SCWT and TMT as observed variables. The established model showed a good fit to the data (χ2 = 1.67, p = 0.43, SRMR = 0.02, RMSEA = 0.0, CFI = 1.00). The highest factor loading was found in WCST as CF explained most of the variance in this neuropsychological measure compared to the other instruments. On the other hand, a TMT ratio index and a SCWT interference demonstrated lowest loadings in the model. The findings suggest that not all the frequently used measures share an underlying factor of CF or may capture different aspects of this construct.

Smoking and attention in schizophrenia spectrum disorders: What are we neglecting?

Introduction: Individuals with schizophrenia spectrum disorders (SSDs) record elevated rates of smoking, which is often attributed to their effort to self-medicate cognitive and attentional symptoms of their illness. Empirical evidence for this hypothesis is conflicting, however. In this study, we aimed to test predictions derived from the cognitive self-medication hypothesis. We predicted that cigarette smoking status and extent would predict the attentional performance of participants with SSDs. Simultaneously, we wished to address methodological gaps in previous research. We measured distinct attentional components and made adjustments for the effects of other, attention-modulation variables. Methods: Sixty-one smokers (82.0% males, 26.73 ± 6.05 years) and 61 non-smokers (50.8% males, 27.10 ± 7.90 years) with recent-onset SSDs completed an X-type Continuous Performance Test, which was used to derive impulsivity and inattention component scores. Relationships between the two component scores and cigarette smoking status and extent were assessed using hierarchical regression. Effects of estimated premorbid intellectual functioning and antipsychotic medication dosage were held constant. Results: Smokers had significantly higher inattention component scores than non-smokers when covariates were controlled (p = 0.026). Impulsivity remained unaffected by smoking status (p = 0.971). Cigarette smoking extent, i.e., the number of cigarettes smoked per day, was not associated with either inattention (p = 0.414) or impulsivity (p = 0.079). Conclusion: Models of smoking-related attentional changes can benefit from the inclusion of sample-specific component scores and attention-modulating covariates. Under these conditions, smokers with SSDs can show a partial attentional benefit. However, the limited scope of this benefit suggests that the cognitive self-medication hypothesis requires further testing or reconsidering.

The relationships between cognitive reserve, cognitive functioning and quality of life in first-episode schizophrenia spectrum disorders.

Cognitive reserve (CR) has been conceptualized as an individual's ability to optimize or maximize performance through differential recruitment of brain networks. As such, CR may contribute to the heterogeneity of cognitive deficits observed in schizophrenia. This study aimed to assess the relationships between CR, cognition and quality of life in first-episode (FES) patients. A total of 137 patients with either ICD-10 schizophrenia or "acute and transient psychotic disorders" diagnosis, and 62 healthy controls had completed a comprehensive assessment of six cognitive domains: speed of processing, attention, working memory/flexibility, verbal memory, visual memory, and abstraction/executive functioning. CR was calculated from the participants' education, premorbid IQ, and socioeconomic status. The results suggested that in patients, CR was positively related to cognitive performance in all domains, explaining 42.6% of the variance observed in cognition overall. Effects of CR in the control group were limited to three domains: speed of processing, abstraction/executive function and working memory/flexibility. These results suggest that CR largely contributes to cognitive variations present in FES patients. In addition, CR was negatively related to the social construct of patients' quality of life, and positively to symptom severity and general functioning.