Browsing by Author "Bulloch, Andrew G. M."

Now showing 1 - 14 of 14
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    Can the adverse childhood experiences (ACEs) checklist be utilized to predict emergency department visits among children and adolescents?
    (2021-09-25) Bhattarai, Asmita; Dimitropoulos, Gina; Marriott, Brian; Paget, Jaime; Bulloch, Andrew G. M.; Tough, Suzanne C.; Patten, Scott B.
    Abstract Background Extensive literature has shown an association of Adverse Childhood Experiences (ACEs) with adverse health outcomes; however, its ability to predict events or stratify risks is less known. Individuals with mental illness and ACE exposure have been shown to visit emergency departments (ED) more often than those in the general population. This study thus examined the ability of the ACEs checklist to predict ED visits within the subsequent year among children and adolescents presenting to mental health clinics with pre-existing mental health issues. Methods The study analyzed linked data (n = 6100) from two databases provided by Alberta Health Services (AHS). The Regional Access and Intake System (RAIS 2016–2018) database provided data on the predictors (ACE items, age, sex, residence, mental health program type, and primary diagnosis) regarding children and adolescents (aged 0–17 years) accessing addiction and mental health services within Calgary Zone, and the National Ambulatory Care Reporting System (NACRS 2016–2019) database provided data on ED visits. A 25% random sample of the data was reserved for validation purposes. Two Least Absolute Shrinkage and Selection Operator (LASSO) logistic regression models, each employing a different method to tune the shrinkage parameter lambda (namely cross-validated and adaptive) and performing 10-fold cross-validation for a set of 100 lambdas in each model were examined. Results The adaptive LASSO model had a slightly better fit in the validation dataset than the cross-validated model; however, it still demonstrated poor discrimination (AUC 0.60, sensitivity 37.8%, PPV 49.6%) and poor calibration (over-triaged in low-risk and under-triaged in high-risk subgroups). The model’s poor performance was evident from an out-of-sample deviance ratio of − 0.044. Conclusion The ACEs checklist did not perform well in predicting ED visits among children and adolescents with existing mental health concerns. The diverse causes of ED visits may have hindered accurate predictions, requiring more advanced statistical procedures. Future studies exploring other machine learning approaches and including a more extensive set of childhood adversities and other important predictors may produce better predictions. Furthermore, despite highly significant associations being observed, ACEs may not be deterministic in predicting health-related events at the individual level, such as general ED use.
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    Dopaminergic transmission in Lymnaea: physiology, pharmacology, and plasticity
    (1996) Magoski, Neil Stephen; Bulloch, Andrew G. M.
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    Evaluating theories of consciousness using the Autonomic Nervous System for comparison
    (1996) Ryder, Thomas Daniel; Martin, Charles B.; Bulloch, Andrew G. M.
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    Met-enkephalin and alpha peptide in lymnaea
    (1993) Ewadinger, Nadine M.; Bulloch, Andrew G. M.
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    Mortality in Individuals with Depression and Problematic Substance Use: A Canadian population-based study
    (2020-11-10) Shafiq, Samreen; Pringsheim, Tamara M.; Patten, Scott B.; Goodarzi, Zahra S.; Bulloch, Andrew G. M.
    The simultaneous presence of depression and problematic substance use is a complex healthcare and public health issue that results in poor mental health outcomes. Individuals with these conditions may be vulnerable to an increased risk of mortality. The purpose of this study is to describe the occurrence and causes of mortality in patients with co-occurrence of major depressive episode (MDE) and problematic substance use in the Canadian household population. The study was performed through the linkage between CCHS Cycle 1.2 to the Canadian Vital Statistics Death Database. Cox proportional hazard model was used to estimate hazard ratios as the measure of association for all-cause mortality. Competing risk regression was used to estimate sub-hazard ratios for injury-related and other causes-related deaths. Interaction analysis between MDE and problematic substance use on the multiplicative (product term) and additive scales (Relative Excess Risk Due to Interaction) was used to determine if the magnitude of effect of problematic substance use or MDE on mortality is modified by the presence of the other disorder. Compared to the general population, the hazard of all-cause mortality was elevated in individuals with MDE (HR: 1.47 (95% CI 1.18–1.82)), problematic substance use (HR: 1.35 (95% CI1.18–1.53)) or with problematic substance use and MDE (HR: 2.13 (95% CI 1.24–3.67)). Individuals with MDE (HR: 3.13 (95% CI 1.82–5.36)), problematic substance use (HR: 1.82 (95% CI 1.22–2.71) or with problematic substance use and MDE (HR: 4.91 (95% CI 1.93–12.51) were also at an increased hazard of injury-related deaths. There was no interaction on the multiplicative or additive scales between the exposures for the outcome of all-cause mortality, injury-related mortality or other causes-related mortality. Individuals with MDE and problematic substance use are at increased hazard of mortality, regardless of the presence of the other exposure. As no interaction was found between MDE and problematic substance use on the multiplicative or additive scale, the simultaneous presence of MDE and substance use doe not increase the strength of association with mortality beyond what is expected given the joint effects of each exposure.
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    Neurotransmitters in Lymnaea interneuron
    (1992) McKenney, Kimberly K.; Bulloch, Andrew G. M.
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    Novel role of integrin ligands in neuromodulation
    (2004) Diep, Chi Que; Bulloch, Andrew G. M.; Wildering, Willem C.
    Integrins, a family of cell adhesion receptors, and their ligands, the extracellular matrix proteins, have been implicated as neuromodulators in the adult CNS. Previous studies from our laboratory on neurons isolated from the CNS of the gastropod snail Lymnaea stagnalis show that integrin peptides increase HVA Ca2+ concentrations and other active intrinsic membrane properties. The current study extends this line of investigation to the intact CNS. Extracellular electrophysiological recording from the trunk of one of the nerves (right internal parietal or RIP nerve) originating from the Lymnaea CNS shows that integrin peptide with the consensus integrin binding motif RDG increases the electrical discharge of some projecting neurons. Further investigations, involving the intracellular recording from 2 synaptic partners that have axonal projections in the RIP nerve, provide evidence that in the Lymnaea CNS integrins play a role in synaptic modulation since they modulate the kinetics of the postsynaptic potentials through synaptic remodeling.
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    Predicting Death by Suicide with Administrative Health Care System Data
    (2020-05-27) Sanderson, Michael; Patten, Scott B.; Bulloch, Andrew G. M.; Wang, Jianli L.; Williamson, Tyler S.
    Quantifying suicide risk with risk scales is common in clinical practice, but the performance of risk scales has been shown to be limited. Prediction models have been developed to quantify suicide risk and have been shown to outperform risk scales, but these models have not been commonly adopted in clinical practice. The original research presented in this thesis as three manuscripts evaluates the performance of prediction models that quantify suicide risk developed with administrative health care system data. The first two manuscripts were designed to determine the most promising prediction model class and temporal data requirements. The modeling dataset contained 3548 persons that died by suicide and 35,480 persons that did not die by suicide between 2000 and 2016. 101 predictors were selected, and these were assembled for each of the 40 quarters prior to the quarter of death, resulting in 4040 predictors for each person. Logistic regression, feedforward neural network, recurrent neural network, one-dimensional convolutional neural network, and gradient boosted trees model classes were compared. The gradient boosted trees model class achieved the best performance and 8 quarters of data at most were required for optimal performance. The third manuscript applied the findings from the first two manuscripts to evaluate the performance of prediction models in a clinical setting. The prediction models quantified the risk of death by suicide within 90 days following an Emergency Department visit for parasuicide. The modeling dataset contained 268 persons that died by suicide and 33,426 persons that did not die by suicide between 2000 and 2017. The predictors were assembled for each of the 8 quarters prior to the quarter of death, resulting in 808 predictors for each person. Logistic regression and gradient boosted trees model classes were compared. The optimal gradient boosted trees model achieved promising discrimination and calibration. Following the manuscripts, this thesis discusses further research. At present, there is no clinical consensus on the preferred performance characteristics for quantifying suicide risk. The critical next step for further research is to discover the preferred performance characteristics for quantifying suicide risk and to discover whether the preferred performance characteristics can be achieved.
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    Predictors of Response to Repetitive Transcranial Magnetic Stimulation Treatment in Adolescent Major Depressive Disorder
    (2018-04-27) McLellan, Quinn Kenneth; MacMaster, Frank P.; Arnold, Paul Daniel; Bulloch, Andrew G. M.
    Adolescent major depressive disorder has limited treatment options and response is unpredictable. Repetitive transcranial magnetic stimulation (rTMS) is a novel treatment option while pre-treatment cortical thickness may be an objective biomarker predictive of response. Twenty-three youth (12-21 years; 11 female) with treatment-resistant depression (TRD) underwent 3 weeks of high-frequency rTMS. Baseline left rostral middle frontal gyrus (lRMF) thickness was compared between eventual responders, non-responders and age-matched controls (n=16; 10 female). Symptom-specific treatment response, defined as ≥50% symptom reduction, was evaluated. Demographic and symptom profile differences were explored. Interventional rTMS alleviated both anxious and depressive symptoms. lRMF was thinner in responders than non-responders, and age negatively correlated with lRMF thickness in controls but not TRD subjects. Exploration of demographic and symptom variables showed responders on the depressive measure had greater frequency of past suicide attempts and higher atypical symptom cluster score while social phobia was associated with non-responsiveness.
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    Regulation of axonal regeneration in helisoma
    (1993) Kruk, Piotr J.; Bulloch, Andrew G. M.
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    Salivary glands of Helisoma
    (1994) Roger, Isabelle; Bulloch, Andrew G. M.
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    The role of tyrosine phosphorylation in neurite outgrowth
    (2000) Larouche, Matthew; Bulloch, Andrew G. M.
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    Trk receptors in Lymnaea
    (2001) Melvin, Neal R.; Bulloch, Andrew G. M.
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    Uncharted Territory: Psychosurgery in Western Canada, 1935-1970
    (2020-01-29) Collins, Brianne M.; Stam, Henderikus J.; Bulloch, Andrew G. M.; Stahnisch, Frank W.; McCoy, Ted; Green, Christopher
    This dissertation provides the first scholarly account of the use of psychosurgery in western Canada in the mid-20th-century. In particular, the adoption, organization, and purpose of the treatment within provincial mental hospitals in British Columbia, Alberta, Saskatchewan, and Manitoba are explored. I argue that while psychosurgery’s adoption in these provinces mirrored its deployment elsewhere in North America, the cumulative impact of decades of overcrowding, inadequate funding, the privations of war, and the devastation of the Great Depression only amplified psychosurgery’s appeal by the early 1940s. Although it was touted as a therapeutic advancement, the treatment—along with three other somatic therapies—enabled psychiatrists in western Canada to bolster their image in the medical community by demonstrating they were capable of actively treating mental illness. From a more critical perspective, I also explore the notion that psychosurgery was employed in service of a larger social agenda ascribed to mental hospitals—namely, the systemic management, control, and correction of a segment of the population that had been deemed a burden to society. Once the treatment was introduced, each province needed to negotiate who would perform the surgeries and how, when, and where they would take place. The expansion of psychosurgery in most of the provinces was ultimately made possible by federal mental health grants that became available in 1948. By 1954, all of the provincial mental hospitals were performing psychosurgery—either on site or in partnership with a nearby general hospital. Based on available data from each province, there were at least 1,240 operations conducted in western Canada between 1943 and 1973. Of the western provinces, however, Manitoba and British Columbia maintained the most robust psychosurgical programs.