Neural Foundations of Mood-Induced Impulsivity and Impulsive Aggression in Schizophrenia

Multiple Early Life Stressors as Risk Factors for Neurodevelopmental Abnormalities in the F1 Wistar Rats

Cumulative exposure to multiple early life stressors is expected to affect behavioral development, causing increased susceptibility to neuropsychiatric disorders. The present study was designed to mimic such conditions in a rat model to study behavioral impairments during adolescence and adulthood. Female Wistar rats (n = 32; 140-150 gm) were switched to a low protein (LP; 8% protein) or control (20% protein) diet 15 days prior to conception, and then the diet regime was maintained throughout the experimental period. Pups born to control and LP dams were intraperitoneally injected with deltamethrin (DLT-pyrethroid insecticide; 0.7 mg/kg body weight; PND 1 to 7), lipopolysaccharide (LPS-bacterial endotoxin; 0.3 mg/kg body weight; PND 3 and 5), or DLT+LPS, on designated days forming eight experimental groups (Control, LP, Control+LPS, LP+LPS, Control+DLT, LP+DLT, Control+DLT+LPS and LP+DLT+LPS). Neurobehavioral assessments were performed in F1 rats (1, 3, 6 months) by open field, elevated plus maze, light and dark box, and rotarod tests. LP rats were found to be highly susceptible to either singular or cumulative exposure as compared to their age-matched control counterparts, showing significantly severe behavioral abnormalities, such as hyperactivity, attention deficits and low anxiety, the hallmark symptoms of neuropsychiatric disorders like schizophrenia and ADHD, suggesting thereby that early life multi-hit exposure may predispose individuals to developmental disorders.

Computerized cognitive and social cognition training in schizophrenia for impulsive aggression

BACKGROUND

Schizophrenia is associated with an elevated risk for impulsive aggression for which there are few psychosocial treatment options. Neurocognitive and social cognitive deficits have been associated with aggression with social cognitive deficits seemingly a more proximal contributor. The current study examined the effects of combining cognitive and social cognition treatment on impulsive aggression among inpatients with chronic schizophrenia and schizoaffective disorder and a history of aggression compared to cognitive remediation treatment alone.

METHODS

The two-center study randomized 130 participants to receive 36 sessions of either a combination of cognitive remediation and social cognition treatment or cognitive remediation plus a computer-based control. Participants had at least one aggressive incident within the past year or a Life History of Aggression (LHA) score of 5 or more. Participants completed measures of neurocognition, social cognition, symptom severity, and aggression at baseline and endpoint.

RESULTS

Study participants were mostly male (84.5 %), had a mean age 34.9 years, and 11.5 years of education. Both Cognitive Remediation Training (CRT) plus Social Cognition Training (SCT) and CRT plus control groups were associated with significant reductions in aggression measures with no group differences except on a block of the Taylor Aggression Paradigm (TAP), a behavioral task of aggression which favored the CRT plus SCT group. Both groups showed significant improvements in neurocognition and social cognition measures with CRT plus SCT being associated with greater improvements.

CONCLUSION

CRT proved to be an effective non-pharmacological treatment in reducing impulsive aggression in schizophrenia inpatient participants with a history of aggressive episodes. The addition of social cognitive training did not enhance this anti-aggression treatment effect but did augment the CRT effect on cognitive functions, on emotion recognition and on mentalizing capacity of our participants.

Feasibility and Utility of Different Approaches to Violence Risk Assessment for Young Adults Receiving Treatment for Early Psychosis

This pilot study examined violence risk assessment among a sample of young adults receiving treatment for early psychosis. In this study, thirty participants were assessed for violence risk at baseline. Participants completed follow-up assessments at 3, 6, 9 and 12 months to ascertain prevalence of violent behavior. Individuals were on average 24.1 years old (SD = 3.3 years) and predominantly male (n = 24, 80%). In this sample, six people (20%) reported engaging in violence during the study period. Individuals who engaged in violence had higher levels of negative urgency (t(28) = 2.21, p = 0.035) This study sought to establish the feasibility, acceptability, and clinical utility of violence risk assessment for clients in treatment for early psychosis. Overall, this study found that most individuals with early psychosis in this study (who are in treatment) were not at risk of violence. Findings suggest that violent behavior among young adults with early psychosis is associated with increased negative urgency.

White matter correlates of impulsivity in frontal lobe and their associations with treatment response in first-episode schizophrenia

BACKGROUND

It is known that increased impulsivity in schizophrenia patients causes poor treatment outcomes by increasing cost, stigma, hospitalization, treatment challenge, and physical harm. Dysfunction in the prefrontal cortex appears to be involved in the impulsivity associated with schizophrenia; nonetheless, there is a dearth of research on specific white matter alterations in the prefrontal cortex related to impulsivity.

METHODS

We enrolled in the present study 119 first-episode schizophrenia patients. We measured their symptom severity at baseline and after eight weeks of treatment, using the positive and negative syndrome scale. We performed neuroimaging analysis using the Tract-Based Spatial Statistics program and by specifying the prefrontal white matter as a region of interest.

RESULTS

In voxel-wise correlational analysis, we observed white matter regions showing significant positive correlations with poor impulse control scores, in both the right dorsolateral prefrontal cortex and the right frontal pole region. The fractional anisotropy values of these areas correlated positively with symptom severity at baseline. Moreover, after eight weeks, treatment non responders showed significantly higher fractional anisotropy values in the same areas.

CONCLUSIONS

The results of the present study suggest that white matter tracts in the right dorsolateral prefrontal cortex and the right frontal pole may underlie dysfunctional impulse control and could be potential predictive markers for short-term treatment in patients with first-episode schizophrenia.

Personality Traits in Individuals with the Dual Diagnosis of Psychosis and Substance Use Disorders: A Comprehensive Review and Meta-Analysis

Substance abuse comorbidity is highly prevalent and is linked to detrimental outcomes in individuals with psychotic disorder, but the role of personality traits as the underlying mechanism is being increasingly underscored. This study aimed to profile temperamental risks of comorbid substance use disorder in psychotic disorders by performing meta-analyses on personality trait differences between psychotic disorders with comorbidity (dual diagnosis; DD) and without it (psychotic disorders; PSD). Methods: A systematic review of English articles using PubMed, MEDLINE, Scopus, Google Scholar, and ProQuest Dissertation and Theses. Only original empirical studies including participants with diagnosis of psychotic disorders based on structured diagnostic interviews, with and without substance use disorder evaluated with reliable and valid tests were included. Articles were independently extracted by two authors using predefined data fields, including study quality indicators. All pooled analyses were based on random-effect models. Thirteen studies (N = 885) met our inclusion criteria. All effect-size estimates were calculated based on means and standard deviations of included measures. Separate effect size estimates were obtained for four traits in the UPPS model (negative urgency, low premeditation, low perseverance, sensation seeking), four traits in the HS model (unconscientious disinhibition, negative affect, disagreeable disinhibition, positive affect) and trait anhedonia. Results: Negative urgency (four studies with 262 participants; ES = 0.59; 95% confidence interval [CI] [0.34, 0.84]), low premeditation (five studies with 349 participants; ES = 0.60; 95% CI [0.39, 0.80]), sensation seeking (seven studies with 550 participants; ES = 0.63; 95% CI [0.17, 1.09]) and unconscientious disinhibition (five studies with 291 participants; ES = 0.36; 95% CI [0.13, 0.59]) were elevated in DD than PSD. Heterogeneity of sensation seeking was significant (I² = 86.2%). Conclusions: The findings of the current meta-analysis highlight a unique profile of impulsive and externalizing trait personality domains pertaining to DD. The study emphasizes the importance of emotion regulation interventions targeting impulsivity or negative affect (i.e. negative urgency, low premeditation) in substance abuse comorbidity patients.

Pathways to aggression and violence in psychosis without longstanding antisocial behavior: A review and proposed psychosocial model for integrative clinical interventions

There is a need for a clearer understanding of the factors associated with increased risk of aggression and violence (AV) among people with psychosis and other severe mental illness (SMI) to guide effective prevention and intervention. The current article (1) reviews the literature regarding psychosocial factors associated with AV among individuals with psychosis and other SMI who do not have longstanding antisocial behaviors, (2) proposes an integrative psychosocial model of AV that can be practically applied, and (3) proposes appropriate evidence-based clinical interventions to reduce AV and facilitate recovery. We propose that increased risk for AV among people with psychosis is driven by anger, which is affected by a range of factors including victimization and situational stressors, social rejection or experiences of discrimination, anxious arousal, and hostile attribution bias related to psychosis. The cumulative effect of these systems is exacerbated by co-occurring substance misuse and increased impulsivity, particularly negative urgency. In consideration of the current psychosocial model and existing evidence-based interventions for AV in individuals with psychosis, we propose that trauma-informed interventions that integrate skills training in emotion regulation, social and interpersonal situations, cognitive restructuring and remediation, and modified prolonged exposure may demonstrate the most promise for this population.

Assessment of coexisting psychosis and substance misuse: complexities, challenges and causality

Substance misuse worsens the prognosis for people suffering psychosis and places them at risk of being denied appropriate mental health service interventions. To increase the chances of its success, the plan of management for patients with coexisting psychosis and substance misuse should be based on a valid formulation of their problems, which in turn is dependent on the clinician having (a) a thorough understanding of the bidirectional and changing ways that substance use and mental illness symptoms can interact, (b) an awareness of their own biased implicit assumptions about causality in explaining these interactions and (c) a framework for assessment and formulation. This article addresses these three areas with reference to the evidence base and to clinical experience in a way that guides mental health clinicians in the assessment of patients with coexisting psychosis and substance misuse.

Do cognitive deficits predict negative emotionality and aggression in schizophrenia?

Schizophrenia is associated with an elevated risk of aggression. Cognitive deficits have been associated with inpatient aggression and future violence. The relationship between cognitive deficits and violent behavior has however been inconsistent across studies. In addition, studies have failed to inform how cognitive deficits may contribute to aggression in schizophrenia. The current study examined the association of cognitive deficits with schizophrenia-related aggression and violent offending. It also explored the putative mediating role of negative emotionality on the impact of cognitive deficits on aggression. People with schizophrenia and schizoaffective disorder (N = 78) were recruited from a state hospital. Participants were classified based on their history of violent offending. Participants completed measures of cognition, symptoms, and aggression. Deficits in working memory, reasoning/problem-solving, and verbal learning were the most prioritized for the prediction of violent offender status. Violent offenders demonstrated greater impairments in most cognitive domains especially working memory and verbal learning. Offenders also demonstrated greater negative emotionality, excitement/agitation, and incidents of verbal and physical aggression. Negative emotionality and excitement/agitation fully transmitted the effect of cognitive deficits on impulsive aggression in meditational models. Cognitive deficits increase the risk of impulsive aggression in schizophrenia via inefficient regulation of negative affective states.