Studies have shown that children and adolescents with neurostructural and/or neurodevelopmental challenges experience worse mental health outcomes than their neurotypical peers, including more extensive service use, more severe symptomatology, and greater functional impairment. Despite the poor prognoses of these children and adolescents, few studies have investigated the neurocognitive contributions to mental health complexity among those seeking community-based mental health services. At present, environmental/social and behavioural factors remain the primary focus of treatment plans and much of the research examining this complex population has targeted psychosocial determinants. However, interventions based on these factors alone are not always effective, as they fail to account for neurocognitive challenges, which can significantly contribute to psychiatric presentations. This dissertation involves two studies that aimed to address these gaps in the literature and inform current practices in paediatric community mental health settings. Using Structural Equation Modeling (SEM), Study 1 tested the generalizability of a path model predicting service use among those with (n = 66) and without (n = 97) neurodevelopmental disorders (NDs). As expected, those with NDs had higher levels of symptomatology and greater service use than those without, and there were notable differences in the predictive pathways across ND groups. Similar paths were found between externalizing challenges and service use among all children/adolescents; however, the paths from internalizing challenges, early life adversity, and sex were only significant among the ND group, indicating that neurodevelopmental status is an important moderator of outcomes. In Study 2, a mixed methods approach was employed to examine how neuropsychological information could help inform current practice. Qualitative results confirmed that neuropsychological factors are often overlooked when utilizing current approaches and that observable symptoms, rather than underlying causes, are a primary focus of treatment. Further, neurocognitive deficits were found to be associated with self-reported interpersonal difficulties and caregivers’ reports of externalizing; however, only caregiver-reported externalizing challenges correlated with poorer treatment outcomes. Importantly, neurocognitive challenges were associated with long-term treatment responses, suggesting that these factors may be an important therapeutic target. Collectively, these findings indicate that using an exclusively psychosocial treatment approach, without considering neuropsychological factors, may not be effective among complex cases.

Land grant to Nicholas Bower, Township of Camden, County of Lenox and Addington, Midland District, son of Adam Bower, U.E. Loyalist. The land grant is for 200 acres of land in the Township of Reach, May 20, 1811. Signed by William Jarvis (Provincial Secretary to the Lt. Governor of Upper Canada); P. Selby (Auditor General); William Firth (Attorney General); and Sir Francis Gore (Lt. Governor of Upper Canada).

Land grant to Elisabeth Merritt, Township of Wainfleet, County of Lincoln, District of Niagara, wife of David Merritt and daughter of Christina Sencebaugh, U.E. Loyalist. The land grant is for 200 acres of land in the Township of Garrafraxa, County of Halton, District of Gore, July 16, 1827. Signed by D. Cameron (Provincial Secretary to the Lt. Governor of Upper Canada); S. Heward (Auditor General); John Robinson (Attorney General); and Sir Peregrine Maitland (Lt. Governor of Upper Canada). Printed on vellum with writing in black ink, ribbon at the bottom and the hard seal displaying the Royal coat of arms.

Report of the Select Committee of the Honourable the Legislative Assembly of the Province of Canada, on the Petition of the Toronto and Lake Huron Rail Road Company, Montreal, February, 1845.

Map of St. Catharines, Merritton, Thorold, and Port Dalhousie. Some streets and lots are visible but not labeled.

“Glenridge” City of St. Catharines, St. Catharines Improvement Company Ltd. A diagram of lots and lot dimensions around Geneva Street, Ontario Street, Dittrick Street and Willowdale Avenue. The right part of the diagram is missing, as well as the top left corner. This affects the text/diagram, n.d.

A clipping with the title “An Imposing Scene at Niagara Camp: Saturday was Review Day and people swarmed in from all points to see the sham fight”, July 3, 1899.

An issue of the Canada Gazette, 31 March 1849. Claimants for Rebellion losses, investigations into possible arson incidents, and crown lands are all mentioned in this issue.

The Upper Canada Gazette, Vol. XIII, No. 28, November 22, 1838. The first page contains a proclamation about the “late unhappy revolt”, and extending “Royal mercy and forgiveness to the deluded and misguided subjects”. The article states that numerous pardons have been granted, but others have been liable to punishment by their misconduct.

The Upper Canada Gazette, Vol. XIL, No. 43, March 8, 1838. The first page contains a schedule of titles of bills passed during the Provincial Parliament. Several acts relate to treason, such as the act to authorize the apprehending and detention of persons suspected of High Treason, Misprision of Treason, and Treasonable Practices. These acts relate to the recent rebellion in Upper Canada in 1837.