Lauren E. Gibson

Trauma and the psychosis spectrum: A review of symptom specificity and explanatory mechanisms

Traumatic life events have been robustly associated with various psychosis outcomes, including increased risk of psychotic disorders, the prodrome of psychosis, and dimensional measures of psychotic symptoms, such as attenuated positive psychotic symptoms. However, trauma exposure has been linked to various mental disorders; therefore, the specificity of trauma exposure to psychosis remains unclear. This review focuses on two understudied areas of the trauma and psychosis literature: 1) the specificity between trauma and psychosis in relation to other disorders that often result post-trauma, and 2) proposed mechanisms that uniquely link trauma to psychosis. We begin by discussing the underlying connection between trauma exposure and the entire psychosis spectrum with a focus on the influence of trauma type and specific psychotic symptoms. We then consider how the principles of multifinality and equifinality can be useful in elucidating the trauma-psychosis relationship versus the trauma-other disorder relationship. Next, we discuss several cognitive and neurobiological mechanisms that might uniquely account for the association between trauma and psychosis, as well as the role of gender. Lastly, we review important methodological issues that complicate the research on trauma and psychosis, ending with clinical implications for the field.

Anxiety mediates the association between cannabis use and attenuated positive psychotic symptoms

Cannabis use has been associated with a continuum of psychotic experiences. However, it is unclear whether mood and anxiety symptoms account for increases in attenuated positive psychotic symptoms (APPS) among cannabis users. We predicted that depression and anxiety symptoms would mediate the relation between cannabis use and APPS, and between cannabis use and endorsement of eight or more distressing APPS (D-APPS), a potentially more clinically meaningful group. Young adults (n=674) completed the Prodromal Questionnaire (PQ); Drug Use Frequency measure; Center for Epidemiologic Studies Depression Scale; State-Trait Anxiety Inventory, Trait Form, Anxiety Subscale; and Social Phobia Scale. Results indicated that symptoms of trait anxiety, but not symptoms of depression or social anxiety, mediated the relationship between cannabis use and APPS, as well as the relationship between cannabis use and D-APPS. Results indicate that symptoms of trait anxiety may play a role in the relation between cannabis use and APPS. Findings underscore the importance of considering clinical characteristics co-occurring with psychotic symptoms, such as affective symptoms, when examining the association between cannabis use and psychotic symptoms.

Schizophrenia and co-occurring substance use disorder: Reward, olfaction and clozapine

Co-occurring substance use disorders (SUD), including alcohol, are common in schizophrenia (SZ) and are associated with poor outcome. Emerging data suggest that individuals with SZ have a dysfunctional brain reward circuit that may underlie their frequent use of alcohol and other substances, and further, that the atypical antipsychotic, clozapine (CLOZ), limits alcohol/substance use in these individuals, potentially by ameliorating this brain reward circuit dysfunction. To explore this hypothesis, reward functioning in a SZ sample with a history of co-occurring SUD, treated with either CLOZ (n=13) or typical antipsychotic agents (TYP), haloperidol or fluphenazine (n=14), as well as healthy controls (n=16), was evaluated through ratings of pleasurable and aversive odors, stimuli that are processed by several neural structures thought to play a key role in processing rewarding stimuli. Results suggest that CLOZ treatment is associated with broadening and strengthening the hedonic experience of these rewarding olfactory stimuli, both of a pleasant and unpleasant nature. This hedonic appraisal of odors appeared to be independent of odor perception (intensity ratings) and clinical symptoms. These preliminary findings provide important new data in support of the hypothesis that CLOZ ameliorates some aspects of abnormal brain reward functioning in individuals with co-occurring SZ and SUD. Further research may have valuable treatment implications for this population including interventions for other reward-associated deficits in learning, social interactions and other aspects of behavior and cognition.

Coping as a mediator of stress and psychotic-like experiences

BACKGROUND There is evidence that individuals along the whole psychosis continuum have increased responsiveness to stress; however, coping responses to stressors have not been extensively explored in subthreshold psychotic symptoms. METHODS In 454 undergraduates, psychotic-like experiences (PLEs) were evaluated using the positive items of the Prodromal Questionnaire. Perceived stress and traumatic life events were assessed using the Life Events Checklist and Perceived Stress Scale, and coping was measured using the Brief COPE. We also examined whether different coping styles mediated the relationship between perceived stress and PLEs, as well as whether different coping styles mediated the relationship between traumatic life events and PLEs. RESULTS Both number of traumatic life events and current level of perceived stress were significantly associated with PLEs. These relationships were both mediated by higher levels of maladaptive coping. CONCLUSIONS Results have the potential to inform treatment strategies, as well as inform targets for exploration in longitudinal studies of those at risk for psychosis.

The association between traumatic life events and psychological symptoms from a conservative, transdiagnostic perspective

Exposure to traumatic life events (TLEs) is strongly linked to the onset and exacerbation of an array of psychological sequelae. While studies yield minimal evidence of specificity for one disorder emerging in the aftermath of TLEs versus another, most studies do not adopt a conservative approach in controlling for multiple psychological symptoms linked to TLEs. The present study explored the association between TLEs and eight psychological constructs before and after adjusting for concurrent symptomatology in a diverse sample of 2342 undergraduates. We predicted three symptom domains would withstand conservative adjustments in their relationship to TLEs: posttraumatic stress disorder (PTSD), borderline personality disorder (BPD), and attenuated positive psychotic symptoms (APPS). Results indicated that exposure to at least one TLE, but especially four or more TLEs, was significantly associated with PTSD and BPD symptoms even after controlling for concurrent symptoms. Additionally, the association between four or more TLEs and APPS persisted despite adjusting for covariates. Findings underscore the critical role that TLE histories play in posttraumatic stress, borderline personality, and attenuated psychotic symptom expression. The relationship between TLEs and depression, cannabis and other drug use, generalized anxiety, and social anxiety disappeared after adjusting for comorbid symptoms.

Attenuated Positive Psychotic Symptoms in Relation to Cigarette Smoking in a Nonclinical Population.

Introduction: This study explored the association between cigarette smoking and attenuated positive psychotic symptoms in a young adult nonclinical sample. Methods: Undergraduates (N = 930), aged 18–35 years (26.3% male), completed a battery of self-report measures assessing subthreshold psychotic symptoms, cigarette smoking behavior/dependence, and drug use. Results: Individuals endorsing a greater number of attenuated positive psychotic symptoms were more likely to be smokers. Exploratory analyses indicated that the odds of being a smoker were two times greater for those at potential higher risk for psychosis compared with individuals at lower risk. Results were consistent after adjusting for sex and other drug use. Conclusions: In line with findings from psychotic populations, results suggest that attenuated positive psychotic symptoms, particularly those endorsed as distressing in a nonclinical, undergraduate population, are related to cigarette smoking. Implications: Even in nonclinical, undergraduate populations, subthreshold psychotic symptoms are related to cigarette smoking, and cigarette smokers are twice as likely to be considered at potentially higher risk for psychosis compared with noncigarette smokers. In summary, there may be a threshold whereby psychotic symptoms confer increased risk for nicotine consumption, with endorsement of a greater number of distressing subthreshold psychotic symptoms increasing the likelihood of cigarette use.

Traumatic life event exposure and psychotic-like experiences: A multiple mediation model of cognitive-based mechanisms

Several cognitive mechanisms have been proposed to account for the relationship between exposure to traumatic life events (TLEs) and the entire psychosis spectrum. However, only few of these mechanisms have been empirically tested and those that have been tested have not considered multiple mechanisms simultaneously. The purpose of this study was to examine whether perceived stress, dissociation, negative self-schemas, negative other-schemas, and/or external locus of control mediated the association between TLEs and psychotic-like experiences (PLEs). An undergraduate sample of 945 individuals completed a battery of self-report questionnaires. We found significant indirect effects from TLE exposure to PLEs through perceived stress, dissociation, external locus of control, negative self-schemas, and negative other-schemas. When controlling for comorbid psychological symptoms, only the indirect effect from TLE exposure to PLEs through dissociation continued to be significant. Targeting stress sensitivity, maladaptive schemas, dissociative tendencies, and externalizing attributional styles may prove useful in the amelioration of risk for various psychopathologies (e.g., mood, psychosis) in the aftermath of TLE exposure. Findings underscore the importance of targeting trauma-related cognitions in the prevention or reduction of psychotic-like experiences or disorders.

Attentional biases and trauma status: Do psychotic-like experiences matter?

Objective: In a large undergraduate sample, we explored whether attentional biases were similar between individuals reporting positive psychotic-like experiences (PLEs) with a history of traumatic life events (TLEs) compared with individuals with a TLE history alone. Method: Participants completed the Emotional Stroop Task, and self-report questionnaires of TLEs and PLEs. Results: Although reaction time (RT) to physical, sexual, emotional, and overall trauma words was associated with TLEs, only RT to physical abuse and overall trauma words remained significantly associated with TLE status after controlling for age, race, and neutral word RT. Contrary to our hypotheses, PLEs were not associated with RT to TLE words and there were no significant interactions between TLE history and PLEs on RT to TLE-salient stimuli. Conclusion: Findings suggest that psychosis risk alone does not appear to exacerbate attentional biases and that TLE history may exert similar influence on attention regardless of psychosis risk. In conclusion, phenotypes associated with TLEs may be similar in populations potentially at risk for psychosis.