Correlations between Negative Symptoms and Cognitive Deficits in Individuals at First Psychotic Episode or at High Risk of Psychosis: A Systematic Review

Current limitations in technology-based cognitive assessment for severe mental illnesses: a focus on feasibility, reliability, and ecological validity

Cognitive impairments are frequently observed in subjects with severe mental illnesses (SMI), leading to a remarkable impact in their real-world functioning. Well-validated and gold standard instruments are available for the assessment of cognitive deficits, but different limitations should be considered, such as the need for specific training, lengthy administration times, practice effects, or reliance on subjective reports. Recent advances in digital technologies, such as ecological momentary assessments (EMA), virtual reality (VR), and passive digital phenotyping (DP), offer promising complementary approaches for capturing real-world cognitive functioning. In the current mini-review, we examine current research gaps that limit the application of these technologies, with a specific focus on feasibility, reliability and ecological validity. EMA may capture real-world functioning by increasing the number of evaluations throughout the day, but its use might be hindered by high participant burden and missing data. Furthermore, to achieve an accurate interpretation of EMA, studies should account for sampling and moment selection biases and the presence of several confounding factors. DP faces significant ethical and logistical challenges, including privacy and informed consent concerns, as well as challenges in data interpretation. VR could serve as a platform for both more ecologically valid cognitive assessments and rehabilitation interventions, but current barriers include technological and psychometric limitations, underdeveloped theoretical frameworks, and ethical considerations. Addressing these issues is crucial for ensuring that these novel technologies can effectively serve as valuable complements to traditional neuropsychological cognitive batteries.

Cognitive function at first episode in patients subsequently developing treatment-resistant schizophrenia

BACKGROUND

Research on cognitive functions in treatment-resistant schizophrenia (TRS) has focused on chronic patients, complicating the distinction between disease-related deficits from those influenced by chronicity or antipsychotic exposure. Identifying early cognitive differences could offer insights into the nature of TRS cognitive performance and serve as potential markers of treatment resistance.

METHODS

Cohort study of 81 first-episode schizophrenia patients from Chile. Patients were followed-up and classified as TRS if they met TRRIP criteria or were prescribed clozapine at any point. 57 healthy controls were recruited for group comparisons. Cognitive performance was assessed using the MATRICS Consensus Cognitive Battery.

RESULTS

51 patients were allocated to the treatment-responsive group (TRESP) and 30 to the TRS sample. Multivariable analyses controlling for age and sex revealed a worse TRS performance in processing speed, verbal fluency, attention/vigilance and working memory (p values <0.05). After multiple comparison corrections, only speed of processing remained significant. When accounting for symptom severity, antipsychotic dose and duration of untreated psychosis (DUP), TRS subjects still showed significantly lower processing speed (BACS, p = 0.036; TMT-A, p = 0.027), which was not significant after correcting for multiple comparisons.

DISCUSSION

TRS patients show slower processing speed compared to TRESP already during first episode, that is not entirely driven by symptom severity, antipsychotic dose and DUP. Processing speed emerges as an early deficit that could aid in the timely identification of patients on a treatment resistance trajectory and facilitate the prompt implementation of treatments such as clozapine.

From Genetics to Psychosocial Functioning: Unraveling the Mediating Roles of Cognitive Reserve, Cognition, and Negative Symptoms in First-Episode Psychosis

BACKGROUND

Studies have shown associations between polygenic risk scores for educational attainment (PRSEA), cognitive reserve (CR), cognition, negative symptoms (NS), and psychosocial functioning in first-episode psychosis (FEP). However, their specific interactions remain unclear. This study aimed to investigate the mediating roles of CR, cognition, and NS in the relationship between PRSEA and psychosocial functioning one year after a FEP. Additionally, we sought to explore the impact of two NS subtypes on this relationship: diminished Expression (EXP-NS) and Motivation and Pleasure (MAP-NS).

METHODS

A total of 138 FEP participants, predominantly male (70%), with a mean age of 24.77 years (SD = 5.29), underwent genetic, clinical, and cognitive assessments two months after study enrollment. Functioning evaluation followed at one-year follow-up. To investigate the mediating role of CR, cognition, and NS in the relationship between PRSEA and functioning, a serial mediation model was employed. Two further mediation models were tested to explore the differential impact of EXP-NS and MAP-NS. Mediation analysis was performed using the PROCESS macro version 4.1 within SPSS version 26.

RESULTS

The serial mediation model revealed a causal chain for PRSEA > CR > cognition > NS > Functioning (β = -3.08, 95%CI [-5.73, -0.43], p = 0.023). When differentiating by type of NS, only EXP-NS were significantly associated in the casual chain (β = -0.17, 95% CI [-0.39, -0.01], p < 0.05).

CONCLUSIONS

CR, cognition and NS -specifically EXP-NS- mediate the association between PRSEA and psychosocial functioning at one-year follow-up in FEP patients. These results highlight the potential for personalized interventions based on genetic predisposition.

Association between cognitive function, antioxidants, and clinical variables in Chinese patients with schizophrenia

OBJECTIVE

Cognitive dysfunction is a prevalent and intricate manifestation of schizophrenia (SCZ) that may be associated with distinct clinical factors and the presence of antioxidants, which relationship is unclear. The study aimed to investigate cognitive function and its influencing factors in Chinese patients with SCZ.

METHODS

A group of 133 patients with SCZ and 120 healthy controls (HCs) were recruited. The MATRICS Consensus Cognitive Battery (MCCB) was utilized to evaluate cognitive ability, and the Positive and Negative Syndrome Scale (PANSS) was used to assess clinical symptoms. Levels of plasma superoxide dismutase (SOD), serum albumin (ALB) and uric acid (UA) were assessed.

RESULTS

Compared with HCs, patients with SCZ exhibited lower cognitive performance as indicated by MCCB scores, including the dimensions of speed of processing, attention/vigilance, working memory, verbal learning, and visual learning. In the SCZ group, total PANSS scores were negatively associated with all MCCB dimensions (all p < 0.05), except for the attention/vigilance score. The PANSS-negative and PANSS-cognitive subscores were negatively associated with speed of processing, verbal learning, and visual learning scores (all p < 0.05). The PANSS-excited subscores showed a negative correlation with working memory and visual learning scores (all p < 0.05). ALB levels significantly decreased, and their UA and SOD levels were notably elevated compared to HCs (all p < 0.05). ALB levels and PANSS-negative factors were correlated with to speed of processing, working memory, and visual learning dimensions. SOD levels were independent contributors to the attention/vigilance dimension.

CONCLUSION

The cognitive function was decreased in SCZ. The degree of cognitive impairment was closely related to ALB, SOD levels and negative clinical symptoms.

The impact of affective and negative symptoms on the development of psychosis in a six-year follow-up of a community-based population

PURPOSE

The Clinical High Risk (CHR) concept has a limited transition risk to psychotic disorders (PD). This study investigates the association between affective and negative symptoms, currently not included in the CHR concept, and the risk of transition to PD in a community-based population of 2185 participants in Turkey.

METHODS

Participants were assessed twice over six years using a multistage sampling technique. Two separate linear regression analyses were conducted on data from both assessments, investigating the relationship between affective and negative symptoms, subclinical and clinical psychotic experiences (PE) and progression to PD.

RESULTS

The overall transition rate to PD was 1.3%. The analysis showed no increased risk of developing PD for the 'subclinical PE only' group at follow-up, compared to the 'no PE' group. However, being classified as having 'clinical PE only' (OR: 6.23; p = 0.010) and 'clinical PE + affective/negative symptoms' (OR: 8.48; p = 0.001) at baseline was associated with an increased risk of developing PD at follow-up. The presence of 'affective/negative symptoms' at baseline was associated with an increased risk of incident subclinical PE (RR: 1.98; p = 0.001), incident clinical PE (RR: 3.14; p = 0.001), and incident PD (RR: 4.21; p = 0.030) at follow-up.

CONCLUSION

The results confirm the significance of the baseline severity of positive symptoms in predicting the transition to PD and suggest that both positive and affective/negative symptoms impact the transition risk to PD and incident psychotic symptoms. This highlights the potential utility of defining CHR groups based on a combination of positive, affective, and negative symptoms.

High-Density Lipoprotein Correlates with Cognitive Functioning in Schizophrenic Women

(1) Background: Schizophrenia is a chronic and progressive neuropsychiatric illness. Apart from positive and negative symptoms, 98% of the population diagnosed with schizophrenia have impaired cognitive functioning, which significantly influences the quality of life. The correlation between lipids and cognitive functioning has been well established. Our study aimed to investigate correlations between cognitive functions, the severity of schizophrenia symptoms, and lipid profiles. (2) Methods: Fifty-two women diagnosed with schizophrenia participated in this study. Cognitive functioning was measured using the Wisconsin Card Sorting Test (WCST). The Positive and Negative Symptom Scale (PANSS) was used. The serum lipid profile, including low-density lipoproteins (LDLs), high-density lipoproteins (HDLs), and triglycerides was measured. (3) Results: Better cognitive functions were associated with normal HDL levels, while low HDL levels correlated with worse WSCT scores. Only the PANSS negative subscale showed a correlation with HDL levels. Correlations with chronicity of schizophrenia and the patient's age with poorer cognitive functions, but not with symptom severity, were detected. Early/late age at onset did not influence WSCT scores. (4) Conclusions: Our results suggest high HDL levels might be a protective factor against cognitive impairment. The influences of age and illness duration also play a vital role in cognitive performance.

Cognitive Inflexibility Predicts Negative Symptoms Severity in Patients with First-Episode Psychosis: A 1-Year Follow-Up Study

Negative symptoms and cognitive deficits play a major role in psychosis and significantly influence the functional outcomes of patients, particularly those with a first episode of psychosis (FEP). However, limited research has explored the predictive capacity of cognitive deficits during FEP for subsequent negative symptomatology. Drawing from the Athens FEP research study, we conducted a retrospective longitudinal study in 80 individuals with FEP. All patients were drug naive at admission. Cognitive tests were administered at 1-month and 1-year post-admission, while negative symptomatology was assessed at the same time points using PANSS by trained raters. We considered confounding factors such as age, gender, duration of untreated psychosis (DUP), treatment received, premorbid social adjustment, and premorbid IQ. Univariate regression analysis identified cognitive domains that correlated with negative symptomatology. These, along with the confounders, were incorporated into a multiple regression, with the 1-year PANSS negative scale serving as the dependent variable. Employing the backward elimination technique, we found a statistically significant inverse relationship between the categories completed in the Wisconsin card sorting test (WCST) and the 1-year PANNS negative scale (p = 0.01), beyond the associations with DUP and the 1-month PANSS negative scale. Our results suggest that cognitive flexibility, a key component of executive functions, predicts negative symptom severity one year after FEP.

Negative Symptoms and Their Associations With Other Clinical Variables and Working Memory Across the Schizophrenia Spectrum and Bipolar Disorder

Negative symptoms (NS) of schizophrenia spectrum disorders (SSD) are also prevalent in bipolar disorder I (BD-I) and show associations with impaired working memory (WM). However, empirical work on their relationship to other clinical factors across SSD and BD-I is sparse. Here, we characterized the associations of NS with key clinical variables and WM capacity across a combined sample of SSD and BD. We included 50 outpatients with SSD and 49 with BD-I and assessed NS domains using SANS global scores for avolition-apathy, anhedonia-asociality, alogia, and blunted affect. We assessed the transdiagnostic relationship between NS and other clinical variables, including positive symptoms, disorganization, depressive symptoms, and antipsychotic medication, using multiple regressions. The strength of these associations was further determined through dominance analyses. Finally, we used multiple regression to assess the relationship between NS domains and WM. To assess the generalizability of transdiagnostic associations, analyses were repeated in each diagnostic group separately. Across SSD and BD-I, disorganization was associated with avolition-apathy and anhedonia-asociality and depressive symptoms additionally predicted anhedonia-asociality. Antipsychotic dose was associated with blunted affect while group differences only predicted alogia. Higher avolition-apathy was related to impaired WM transdiagnostically, partially mediated by the severity of disorganization, whereas only in BD-I higher anhedonia-asociality was associated with better WM capacity. This study demonstrated transdiagnostic associations of both avolition-apathy and anhedonia-asociality with disorganization and identified avolition-apathy as a potential transdiagnostic predictor of WM impairments. Overall, our findings highlight the importance of understanding the relationship between NS domains and other clinical factors with cognitive function across SSD and BD.