We previously reported that dual injections of lipopolysaccharide (LPS) in mice constitute a valuable tool for investigating the contribution of inflammation to psychotic disorders. The present study investigated how immune activation affects the kynurenine pathway and rat behaviour of relevance for psychotic disorders.

Male Sprague Dawley rats were treated with either dual injections of LPS (0.5 mg/kg + 0.5 mg/kg, i.p.) or dual injections of saline. Twenty-four hours after the second injection, behavioural tests were carried out, including locomotor activity test, fear conditioning test, spontaneous alternation Y-maze test, and novel object recognition test. In a separate batch of animals, in vivo striatal microdialysis was performed, and tryptophan, kynurenine, quinolinic acid, and kynurenic acid (KYNA) in the dialysate were measured using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

Dual-LPS treatment decreased spontaneous locomotion, exaggerated d-amphetamine-induced locomotor activity, and impaired recognition memory in male Sprague-Dawley rats. In vivo microdialysis showed that dual-LPS treatment elicited metabolic disturbances in the kynurenine pathway with increased extracellular levels of kynurenine and KYNA in the striatum.

The present study further supports the feasibility of using the dual-LPS model to investigate inflammation-related psychotic disorders and cognitive impairments.

Early-life adversity (ELA) is one of the strongest predictors of childhood depression that may be exacerbated by a genetic predisposition to develop depression. We therefore investigated the bio-behavioural effects of an early-life stressor in an accepted rodent model of depression.

The Flinders sensitive line (FSL) and resistant line (FRL) rats were subjected to an early-life stressor, whereafter their bio-behavioural response during pubertal onset was evaluated. Male and female pups were maternally separated for 3 h per day from postnatal day 02 (PND02) to 17, when they were also weaned. Control animals were left undisturbed, until weaning on PND21. Depressive-like behaviour was analysed on PND21 and reassessed on PND36. Hippocampal monoamine levels, markers of oxidative stress and metabolic markers implicating mitochondrial function were also measured.

On PND21, the non-maternal separation and early weaning (non-MSEW) FSL rats spent 10% more time mobile than their FRL controls in the tail suspension test (TST) yet displayed increased depressive-like behaviour in the forced swim test (FST) on PND36. This depressive-like behaviour coincided with increased hippocampal norepinephrine levels, serotonin turnover and a dysfunctional redox state. Maternal separation and early weaning (MSEW) appeared to initially reduce early-life (PND21) depressive-like behaviour in the TST but then induced depressive-like behaviour on PND36 and increased norepinephrine levels more profoundly in the FRL rats.

These findings highlight the need to further investigate the stress response pathway in these animals and that the absence or presence of genetic susceptibility may influence the presentation of ELA effects.

In sub-Saharan Africa, there are no validated screening tools for delirium in older adults, despite the known vulnerability of older people to delirium and the associated adverse outcomes. This study aimed to assess the effectiveness of a brief smartphone-based assessment of arousal and attention (DelApp) in the identification of delirium amongst older adults admitted to the medical department of a tertiary referral hospital in Northern Tanzania.

Consecutive admissions were screened using the DelApp during a larger study of delirium prevalence and risk factors. All participants subsequently underwent detailed clinical assessment for delirium by a research doctor. Delirium and dementia were identified against DSM-5 criteria by consensus.

Complete data for 66 individuals were collected of whom 15 (22.7%) had delirium, 24.5% had dementia without delirium, and 10.6% had delirium superimposed on dementia. Sensitivity and specificity of the DelApp for delirium were 0.87 and 0.62, respectively (AUROC 0.77) and 0.88 and 0.73 (AUROC 0.85) for major cognitive impairment (dementia and delirium combined). Lower DelApp score was associated with age, significant visual impairment (<6/60 acuity), illness severity, reduced arousal and DSM-5 delirium on univariable analysis, but on multivariable logistic regression only arousal remained significant.

In this setting, the DelApp performed well in identifying delirium and major cognitive impairment but did not differentiate delirium and dementia. Performance is likely to have been affected by confounders including uncorrected visual impairment and reduced level of arousal without delirium. Negative predictive value was nevertheless high, indicating excellent ‘rule out’ value in this setting.

Cognitive dysfunction in schizophrenia may be assessed by measuring within-individual variability (WIV) in performance across a range of cognitive tests. Previous studies have found increased WIV in people with schizophrenia, but no studies have been conducted in low- to middle-income countries where the different sociocultural context may affect WIV. We sought to address this gap by exploring the relationship between WIV and a range of clinical and demographic variables in a large study of people with schizophrenia and matched controls in South Africa.

544 people with schizophrenia and 861 matched controls completed an adapted version of The University of Pennsylvania Computerized Neurocognitive Battery (PennCNB). Demographic and clinical information was collected using the Structured Clinical Interview for DSM-IV Diagnoses. Across-task WIV for performance speed and accuracy on the PennCNB was calculated. Multivariate linear regression was used to assess the relationship between WIV and a diagnosis of schizophrenia in the whole sample, and WIV and selected demographic and clinical variables in people with schizophrenia.

Increased WIV of performance speed across cognitive tests was significantly associated with a diagnosis of schizophrenia. In people with schizophrenia, increased speed WIV was associated with older age, a lower level of education and a lower score on the Global Assessment of Functioning scale. Increased accuracy WIV was significantly associated with a younger age in people with schizophrenia.

Measurements of WIV of performance speed can add to the knowledge gained from studies of cognitive dysfunction in schizophrenia in resource-limited settings.

Chronic stress responses can lead to physical and behavioural health problems, often experienced and observed in the care of people with intellectual disabilities or people with dementia. Electrodermal activity (EDA) is a bio-signal for stress, which can be measured by wearables and thereby support stress management. However, the how, when and to what extent patients and healthcare providers can benefit is unclear. This study aims to create an overview of available wearables enabling the detection of perceived stress by using EDA.

Following the PRISMA-SCR protocol for scoping reviews, four databases were included in the search of peer-reviewed studies published between 2012 and 2022, reporting detection of EDA in relation to self-reported stress or stress-related behaviours. Type of wearable, bodily location, research population, context, stressor type and the reported relationship between EDA and perceived stress were extracted.

Of the 74 included studies, the majority included healthy subjects in laboratory situations. Field studies and studies using machine learning (ML) to predict stress have increased in the last years. EDA is most often measured on the wrist, with offline data processing. Studies predicting perceived stress or stress-related behaviour using EDA features, reported accuracies between 42% and 100% with an average of 82.6%. Of these studies, the majority used ML.

Wearable EDA sensors are promising in detecting perceived stress. Field studies with relevant populations in a health or care context are lacking. Future studies should focus on the application of EDA-measuring wearables in real-life situations to support stress management.