Aberrant adapting of beliefs under stress: a mechanism relevant to the formation of paranoia?

Background Difficulties in the ability to adapt beliefs in the face of new information are associated with psychosis and its central symptom – paranoia. As cognitive processes and psychotic symptoms are both known to be sensitive to stress, the present study investigated the exact associations between stress, adapting of beliefs [reversal learning (RL), bias against disconfirmatory evidence (BADE), and jumping to conclusions (JTC)] and paranoia. We hypothesized that paranoia would increase under stress and that difficulties in adapting of beliefs would mediate or moderate the link between stress and paranoia. Furthermore, we hypothesized that the investigated effects would be strongest in the group of individuals diagnosed with a psychotic disorder. Methods We exposed 155 participants (38 diagnosed with a psychotic disorder, 40 individuals with attenuated psychotic symptoms, 39 clinical controls diagnosed with an obsessive-compulsive disorder, and 38 healthy controls) to a control condition and a stress condition, in which we assessed their levels of paranoia and their ability to adapt beliefs. We applied multilevel models to analyze the data. Results Paranoia was higher in the stress condition than in the control condition, b = 1.142, s.e. = 0.338, t(150) = 3.381, p < 0.001. RL, BADE, and JTC did not differ between conditions and did not mediate or moderate the association between stress and paranoia (all ps > 0.05). Conclusions The results support the assumption that stress triggers paranoia. However, the link between stress and paranoia does not seem to be affected by the ability to adapt beliefs.

Exploring Depressive Symptoms Among Healthcare Professionals and the General Population During the COVID-19 Pandemic in Brazil

Our study aimed to examine the symptoms that might play a role in the co-occurrence of 9 DSM-5 symptom criteria of major depression among Brazil's adult population and healthcare professionals after three months of detecting the new coronavirus in Brazil. We estimated regularized Gaussian graphical models for both samples and compared the network structures. Depressed mood was the most central symptom in the general population network compared to the healthcare professional network. The findings revealed some individual symptoms showed a differential association between the general population and healthcare professionals. Those symptoms may be valuable targets for future research and treatment.

Striatal dopamine mediates hallucination-like perception in mice

Hallucinations, a central symptom of psychotic disorders, are attributed to excessive dopamine in the brain. However, the neural circuit mechanisms by which dopamine produces hallucinations remain elusive, largely because hallucinations have been challenging to study in model organisms. We developed a task to quantify hallucination-like perception in mice. Hallucination-like percepts, defined as high-confidence false detections, increased after hallucination-related manipulations in mice and correlated with self-reported hallucinations in humans. Hallucination-like percepts were preceded by elevated striatal dopamine levels, could be induced by optogenetic stimulation of mesostriatal dopamine neurons, and could be reversed by the antipsychotic drug haloperidol. These findings reveal a causal role for dopamine-dependent striatal circuits in hallucination-like perception and open new avenues to develop circuit-based treatments for psychotic disorders.

Depressive rumination is correlated with brain responses during self-related processing

BackgroundRumination, a tendency to focus on negative self-related thoughts, is a central symptom of depression. Studying the self-related aspect of such symptoms is challenging due to the need to distinguish self effects per se from the emotional content of task stimuli. This study employs an emotionally neutral self-related paradigm to investigate possible altered self processing in depression and its link to rumination.MethodsPeople with unipolar depression (MDD; n = 25) and controls (n = 25) underwent task-based EEG recording. Late event-related potentials were studied along with low frequency oscillatory power. EEG metrics were compared between groups and correlated with depressive symptoms and reported rumination.ResultsThe MDD group displayed a difference in late potentials across fronto-central electrodes between self-related and non-self-related conditions. No such difference was seen in controls. The magnitude of this difference was positively related with depressive symptoms and reported rumination. MDD also had elevated theta oscillation power at central electrodes in self-related conditions, which was not seen in controls.ConclusionsRumination appears linked to altered self-related processing in depression, independently of stimuli-related emotional confounds. This connection between self-related processing and depression may point to self-disorder being a core component of the condition.

Network analysis of impulse dyscontrol in mild cognitive impairment and subjective cognitive decline

ABSTRACT Objectives: To investigate conditional dependence relationships of impulse dyscontrol symptoms in mild cognitive impairment (MCI) and subjective cognitive decline (SCD). Design: A prospective, observational study. Participants: Two hundred and thirty-five patients with MCI (n = 159) or SCD (n = 76) from the Prospective Study for Persons with Memory Symptoms dataset. Measurements: Items of the Mild Behavioral Impairment Checklist impulse dyscontrol subscale. Results: Stubbornness/rigidity, agitation/aggressiveness, and argumentativeness were frequent and the most central symptoms in the network. Impulsivity, the fourth most central symptom in the network, served as the bridge between these common symptoms and less central and rare symptoms. Conclusions: Impulse dyscontrol in at-risk states for dementia is characterized by closely connected symptoms of irritability, agitation, and rigidity. Compulsions and difficulties in regulating rewarding behaviors are relatively isolated symptoms.

Posttraumatic Stress Disorder Near and Far: Symptom Networks From 2 to 12 Months After the Virginia Tech Campus Shootings

Posttraumatic stress disorder (PTSD) is unique in its longitudinal focus. To better understand how PTSD develops, we used network analysis in a longitudinal sample of survivors of the 2007 Virginia Tech campus shootings. Participants were 212 women who completed surveys at both 2 and 12 months after the shooting. Using within-group permutation tests, we found that overall network strength significantly increased and overall network structure significantly changed. Several symptoms saw marked alterations in their network centrality and relations to other symptoms. Psychological reactivity at reminders was the most central symptom at 2 months but among the least central at 12 months. By contrast, reliving, anhedonia, and physiological reactivity had low centrality at 2 months but high centrality at 12 months. Findings broadly support memory-based and fear-conditioning accounts of PTSD and suggest that automatic situationally cued symptoms, including reliving, thought avoidance, and physiological reactions, become more central to the network over time.

Tackling Fearful Avoidance using Counterconditioning: A Causal Test for the Role of Appetitive Motivation in Fearful Avoidance Behaviour

Anxiety disorders are prevalent in the population and costly for society, while current treatment is not effective in all individuals. A central symptom of anxiety is avoidance behaviour, with excessive avoidance being predictive of poor clinical outcomes. Appetitive motivation could play a role in decreasing avoidance behaviour by increasing the positive valuation of the feared object. The current study used an approach-avoidance conflict paradigm to measure costly avoidance behaviour in a healthy group of 22 participants. During counterconditioning training one stimulus was followed by eating a tasty snack (CS+), while another was never followed by an outcome (CS-). Results indicated that the CC-training was effective in reducing negative valuation and decreasing avoidance behaviour for the CS+. This study showed the importance of appetitive motivation for avoidance behaviour, suggesting that treatment may benefit from focussing on increasing appetitive motivation to overcome avoidance.

PTSD Near and Far: Symptom Networks from Two to 12 Months after the Virginia Tech Campus Shootings

Posttraumatic stress disorder (PTSD) is unique in its longitudinal focus. To better understand how PTSD develops, we used network analysis in a longitudinal sample of survivors of the 2007 Virginia Tech campus shootings. Participants were 212 women who completed surveys at both two and 12 months post-shooting. Using within-group permutation tests, we found that overall network strength significantly increased and overall network structure significantly changed. Several symptoms saw marked alterations in their network centrality and relations to other symptoms. Psychological reactivity at reminders was the most central symptom at two months but among the least central at 12 months. By contrast, reliving, anhedonia, and physiological reactivity had low centrality at two months but high centrality at 12 months. Findings broadly support memory-based and fear conditioning accounts of PTSD and suggest that automatic situationally-cued symptoms, including reliving, thought avoidance, and physiological reactions, become more central to the network over time.