Kristina M Gicas

• PhD
• Professor (Assistant) at University of the Fraser Valley

Objective: Many individuals living in precarious housing or homelessness have multimorbid illnesses, including substance use, psychiatric, and neurological disorders. Movement disorders (MDs) associated substance use are amongst the poorly studied subtopics of drug-induced MDs. The aim of the present study was, therefore, to determine the proporti...

Background: Homeless and precariously housed persons exhibit significant memory impairment, but the component processes underlying memory dysfunction have not been explored. We examined the serial position profile (i.e., primacy and recency effects) of verbal memory and its neuroanatomical correlates to identify the nature of memory difficulties in...

Background Homeless or precariously housed individuals live with poor health and experience premature mortality compared with the general population, yet little is known about age-related brain changes among these individuals. We evaluated whether MRI measures of brain structure are differentially associated with age and selected risk factors among...

Objective: Homeless adults represent a marginalized group with numerous psychiatric and physical illness risk factors for poor functional outcomes. This study investigated bidirectional associations between housing stability and neurocognitive functioning in homeless adults using a longitudinal study design. Method: Participants were homeless adult...

Objective: This study examined the relationship between mild traumatic brain injury (mTBI) history, mental health, and sex with single and polysubstance use in university athletes. Design: Observational study. Setting: University in Ontario, Canada. Participants: Participants were identified from a dataset of 416 university athletes ages 18...

Objective Serial position scores on verbal memory tests are sensitive to early Alzheimer’s disease (AD)-related neuropathological changes that occur in the entorhinal cortex and hippocampus. The current study examines longitudinal change in serial position scores as markers of subtle cognitive decline in older adults who may be in preclinical or at...

Cavities in the hippocampus are morphological variants of uncertain significance. Aberrant neurodevelopment along with vascular and inflammatory etiologies have been proposed. We sought to characterize these cavities and their potential risk factors in a marginally housed population, with high rates of viral infection, addiction, and mental illness...

Background: While there is an established link between untreated psychosis and aggression, an enhanced understanding of the role of social cognition is still needed. Aims: To examine social cognitive functioning among patients in a specialist forensic mental health service who had been deemed not criminally responsible for acts of violence due t...

Background Homeless and precarious housed persons are particularly prone to traumatic brain injuries (TBIs), but existent incidence rates are hampered by poor case acquisition. We rigorously documented TBIs in precariously housed persons transitioning in and out of homelessness. Methods Between December 2016 and May 2018, 326 precariously housed...

Background: Homeless and precarious housed persons are particularly prone to traumatic brain injuries (TBIs), but existent incidence rates are hampered by poor case acquisition. We rigorously documented TBIs in precariously housed persons transitioning in and out of homelessness. Methods: Between December 2016 and May 2018, 326 precariously housed...

Longitudinal studies of substance-induced psychosis (SIP) suggest that approximately 11-46% of persons will progress to schizophrenia with differential risk of progression depending on the type of substance used. The findings suggest SIP may be a distinct variant of a psychotic disorder, yet SIP is understudied and the disease expression is not wel...

Importance Homeless or precariously housed individuals live with poor health and experience premature mortality compared to the general population. With an increasing average age among this demographic, syndromes associated with neurogenerative disease are also increasing. Quantitative MRI measures may help define the roles of age and risk factors...

Background : Although homeless or precariously housed populations have a high prevalence of depression, the suitability of existing symptom measurement tools remains unknown. The present study explores the psychometric properties and correlates of the Beck Depression Inventory (BDI) in a community-based sample. Methods : 475 participants recruited...

Background opioid use, which includes both prescribed and non-prescribed drugs, is relatively common amongst marginalized populations. Past research has shown that among those who use non-prescribed or diverted opioids recreationally, many were first exposed to the drug as prescribed pain medication. Objective: to better understand the relationship...

The Iowa Gambling Task (IGT) is a widely used measure of decision making, but its value in signifying behaviors associated with adverse, “real-world” consequences has not been consistently demonstrated in persons who are precariously housed or homeless. Studies evaluating the ecological validity of the IGT have primarily relied on traditional IGT s...

University athletes are at high risk for both substance use and mental health problems. This study examined associations between substance use, mental health symptoms, and the resting state functional connectivity (rsFC) of key neural regions involved in self-monitoring and emotional regulation in a sample of female varsity athletes. 31 female univ...

Background High rates of physical and mental health comorbidities are associated with functional impairment among persons who are homeless. Cognitive dysfunction is common, but how it contributes to various functional outcomes in this population has not been well investigated. This study examines how cognition covaries with community functioning an...

Objective: Traumatic brain injury (TBI) is increasingly recognized as a common and impactful health determinant in homeless and precariously housed populations. We sought to describe the history of TBI in a precariously housed sample and evaluate how TBI was associated with the initial loss and lifetime duration of homelessness and precarious hous...

Background Post-traumatic Stress Disorder (PTSD) often does not respond to available treatments. Memories are vulnerable to disruption during reconsolidation, and electroconvulsive therapy (ECT) has amnestic effects. Objective/Hypothesis To test the use of ECT to disrupt the reconsolidation of traumatic memories as a potential treatment for PTSD....

Background People living in precarious housing or homelessness have higher than expected rates of psychotic disorders, persistent psychotic symptoms, and premature mortality. Psychotic symptoms can be modeled as a complex dynamic system, allowing assessment of roles for risk factors in symptom development, persistence, and contribution to premature...

Few studies to date have examined the utility of the Personality Assessment Inventory (PAI) in predicting aggressive behaviour among those deemed ‘not criminally responsible on account of a mental disorder.’ In this pilot study, 25 forensic psychiatric patients with a history of violence and diagnosed with psychosis and 20 healthy controls complete...

Objective: To determine whether serial position scores in verbal memory differentiate hippocampal-related neuropathologic outcomes, we examined these associations in a sample of nondemented older adults who underwent autopsy. Methods: We used data from the Rush Memory and Aging Project; a longitudinal clinical-pathologic cohort study of communit...

Ce sondage visait à éclairer la formation de niveau supérieur en matière d’évaluation psychologique clinique en identifiant les stratégies, les obstacles et les besoins des psychologues dans la gestion des activités de formation en évaluation à l’ère COVID-19. Un sondage national en ligne en anglais et en français a été proposé à des psychologues a...

Introduction Post-traumatic Stress Disorder (PTSD) often does not respond to available treatments. Memories are vulnerable to disruption during reconsolidation, and electroconvulsive therapy (ECT) has amnestic effects. We sought to exploit this phenomenon as a potential treatment for PTSD with a clinical trial of patients with PTSD receiving ECT....

Background and purpose: We aim to describe the burden, characteristics, and cognitive associations of cerebral small vessel disease in a Canadian sample living with multimorbidity in precarious housing. Methods: Participants received T1, T2-fluid-attenuated inversion recovery, and susceptibility-weighted imaging 3T magnetic resonance imaging seque...

Longitudinal studies of cannabis exposure during early adolescence in the general population frequently report an increased risk of subsequently developing psychotic symptoms or a psychotic illness. However, there is a dearth of knowledge about the effects of early cannabis exposure on psychosis in homeless and precariously housed adults, who repre...

Background The “trimorbidity” of substance use disorder and mental and physical illness is associated with living in precarious housing or homelessness. The extent to which substance use increases risk of psychosis and both contribute to mortality needs investigation in longitudinal studies. Methods and findings A community-based sample of 437 adu...

Objective: The amygdala is a brain region comprised of a group of functionally distinct nuclei that play a central role in social behavior. In homeless and precariously housed individuals, high rates of multimorbidity, and structural aspects of the environment may dysregulate social functioning. This study examined the neurobiological substrates of...

Objective Individuals with early psychosis may have prefrontal-limbic cortical deficits, which are associated with symptom severity and cognitive impairment. This study investigated the impact of an exercise intervention on fronto-temporal cortical plasticity in female participants with early psychosis. Methods In a cohort of 51 female participant...

Background Homeless and precariously housed individuals experience a high burden of comorbid illnesses, and excess mortality. Cross-sectional studies report a high rate of cognitive impairment. Long-term trajectories have not been well investigated in this group. Aims To longitudinally assess risks for premature and/or accelerated cognitive ageing...

Rationale Schizophrenia and stimulant-induced psychosis (SIP) represent two different forms of psychotic disorder, with different etiologies. While many of the symptoms of psychosis are common to both disorders, there have been few direct comparisons between these conditions, especially when controlling for stimulant use in individuals with schizop...

Background: Cannabis is commonly used for its medical properties. In particular, cannabis is purported to have beneficial effects on a wide range of neuropsychiatric conditions. Studies assessing mental health in cannabis dispensary users typically evaluate symptoms using self-report check lists, which provide limited information about symptom sev...

Objective: Homeless and marginally housed youth are particularly vulnerable members of society, and are known to experience numerous health problems, including psychiatric illness, substance use, and viral infection. Despite the presence of these risk factors for cognitive compromise, there is limited research on the cognitive functioning of homele...

We characterized the prevalence, mechanisms, and sex difference of lifetime traumatic brain injury (TBI) in a precariously housed sample. We also examined the impact of TBI severity and timing on becoming and staying homeless. 285 precariously housed participants (adults n = 226, youths n = 59) completed the Brain Injury Screening Questionnaire (BI...

Background Homeless and vulnerably housed individuals are at increased risk for multimorbidity compared with the general population. We assessed prevalence of brain infarcts on neuroimaging and associations with vascular risk factors and cognitive performance in a prospective study of residents living in marginal housing. Methods and Results Two h...

Introduction Cognition is impaired in homeless and vulnerably housed persons. Within this heterogeneous and multimorbid group, distinct profiles of cognitive dysfunction are evident. However, little is known about the underlying neurobiological substrates. Imaging structural covariance networks provides a novel investigative strategy to characteriz...

Objective We investigated white matter differences associated with distinct neurocognitive profiles derived from a large cohort of marginally housed persons with comorbid physical and mental illnesses. Our prior work identified three profile cluster groups: a high functioning group (Cluster 1), a low functioning group with relative strength in deci...

Recent studies associated schizophrenia with enhanced functionality of the presynaptic SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complex. Altered degradation pathways of the three core SNARE proteins: synaptosomal-associated protein 25 (SNAP25), syntaxin-1 and vesicle-associated membrane protein (VAMP) could cont...

OBJECTIVE: Persons who are homeless or marginally housed exhibit significant cognitive dysfunction, with memory being the most impaired domain. Hippocampal subfield volumes have been found to differentially relate to component processes of memory. The neural correlates of memory have not been previously examined in marginalized persons who are unde...

Background: Schizophrenia is associated with poor cognitive function and elevated cardiometabolic disease risk. These health concerns may exacerbate neurocognitive dysfunction associated with hippocampal abnormalities, particularly hippocampal volume reductions. Regular exercise is thought to improve symptom severity, reduce depression, and improv...

Background Atypical antipsychotics are thought to normalize structural morphology in subcortical regions, however their effect on cortical volume remains equivocal.1,2 Studying the impact of atypical antipsychotic treatment on cortical structure in drug-naïve first-episode psychosis (FEP) patients is an opportunity to elucidate the effects of illne...

Background Verbal memory impairment is a core feature in schizophrenia even at early stages of the disease, but its etiopathogenesis is not fully understood. The APOE-ε4 is the main genetic risk factor for late-onset Alzheimer’s disease. Our primary goal was to ascertain whether APOE-ε4 status had a pleiotropic effect in early stages of the illness...

Methods: Detailed mental and physical health structured interviews, neuropsychological testing, and multimodal MRI were performed on 283 participants. Two traumatic brain injury (TBI) participant groups were defined for primary analyses: those with a self-reported history of TBI and those with MRI evidence of TBI. Results: By self-report, 174 pa...

RationaleThe psychostimulant drugs cocaine and methamphetamine are potent indirect dopamine receptor agonists which act through similar but not identical mechanisms. Studies in humans have observed that a large proportion of those who chronically use these drugs experience psychotic symptoms. However, direct comparisons of psychotic symptom severit...

Background: This study examined the characteristics and associated risk and protective factors of distinct psychotic symptom profiles exhibited by marginally housed adults. Methods: The Hotel Study is a longitudinal observational study of adults living in marginalized housing. Five psychosis symptoms (delusions, conceptual disorganization, hallucin...

Background: The psychostimulant drugs, cocaine and methamphetamine, are potent, indirect dopamine receptor agonists. Sustained use of high doses of these drugs can result in psychotic symptoms in a large proportion of individuals. However, there is a shortage of information about how this type of drug-induced psychosis compares to the psychotic sym...

Objective: The Hotel Study was initiated in Vancouver's Downtown East Side (DTES) neighborhood to investigate multimorbidity in homeless or marginally housed people. We evaluated the clinical effectiveness of existing, illness-specific treatment strategies and assessed the effectiveness of health care delivery for multimorbid illnesses. Method:...

Background: White Matter Hyperintensities (WMH) are features of cerebral small vessel disease (cSVD) along with lacunes, cerebral microbleeds and perivascular spaces. Vascular risk factors account for only a small proportion of the variability of the presence of WMH, and the role of additional risk factors including drug use/dependence or infection...

The authors examined associations between complementary fronto-temporal structural brain measures (gyrification, cortical thickness) and neurocognitive profiles in a multimorbid, socially marginalized sample. Participants were recruited from single-room occupancy hotels and a downtown community courthouse ( = 299) and grouped on multiple neurocogni...

Approximately half of psychostimulant users experience psychotic symptoms, which include both positive and negative symptoms. Prior reports have exclusively used positive symptoms to characterize psychostimulant associated psychosis. Symptoms vary dramatically in severity, though most investigations categorize psychosis as a dichotomous occurrence....

With sufficient drug exposure, some individuals develop transient psychotic symptoms referred to as ‘substance-induced psychosis’ (SIP), which closely resemble the symptoms observed in schizophrenia spectrum disorders. The comparability in psychotic presentation between SIP and the schizophrenias suggests that similar underlying neural deficits may...

Introduction: Individuals living in single-room occupancy (SRO) hotels constitute a socially marginalized group with exposure to multiple factors with adverse effects on neurocognition, including substance use, viral infection, psychiatric illness, and brain injury. Consequently, marked heterogeneity in neurocognitive functioning is observed. This...

Due to its functional association to executive functioning, the study of the morphological configuration of prefrontal cortex (PFC) in neurodevelopmental disorders is of great relevance in neuropsychology. One robust example comes from the neuroimaging literature in Attention Deficit/Hyperactivity Disorder (ADHD). Our study aimed to examine the sen...