Ontario Review Board
Re: Treena Isbister
ORB File No: 4071
Hearing held on: Monday, October 20, 2025
Place of Hearing: Brockville Mental Health Centre
Pursuant to: Section 672.81(1) of the Criminal Code
Before:
Alternate Chairperson: Ms. L. Silver
Members: Dr. R. Kunjukrishnan Dr. M. Green Ms. J. Fuller Ms. K. Brisson
Parties Appearing:
Accused: Treena Isbister Counsel: Mr. M. Davies
Person in charge of hospital: Counsel: Ms. P. Miltenburg Representative: Dr. R. Linthorst
Attorney-General of Ontario: Counsel: Ms. J. Masse
REASONS FOR DISPOSITION
(Dated November 25, 2025)
Introduction:
On November 2, 2004, Treena Isbister was found not criminally responsible on account of mental disorder on charges of assault and failure to comply with a probation order, all contrary to the Criminal Code.
Ms. Isbister is currently subject to an Ontario Review Board Disposition of October 29, 2024, which requires her to be detained at the Brockville Mental Health Centre (BMHC) with privileges, including the ability to live in the community within 350 kilometres of the Brockville Mental Health Centre.
On June 10th, 2024, Ms. Isbister was discharged to a supervised housing group home, Le Manoir Caledonia, located in St. Isidore, Ontario, where she has resided since.
On October 20th, 2025, the Ontario Review Board convened at the BMHC to review last year’s Disposition. Ms. Isbister appeared in person and was represented by counsel, Mr. Michael Davies.
The issues before the Board were whether Ms. Isbister continues to present a significant risk to public safety, and if so, to determine the necessary and appropriate disposition.
Initial Position of the Parties
At the outset of the hearing, the hospital submitted that Ms. Isbister continues to present a significant threat to the safety of the public, but that her risk could be adequately managed through a conditional discharge requiring her to reside in approved accommodation. Ms. Masse, on behalf of the Attorney-General, largely agreed with the hospital’s submission but indicated that she wished to pose several questions. Mr. Davies, on behalf of his client, also agreed with the proposed conditional discharge.
For the reasons outlined below, the Board agreed that a conditional discharge constitutes the appropriate disposition in this case.
Current Psychiatric Diagnoses
- Ms. Isbister’s current psychiatric and medical diagnoses are as follows:
- Schizoaffective Disorder, Bipolar Type
- Alcohol and Cannabis Use Disorders in forced remission
- Obstructive Sleep Apnea
- Metabolic Syndrome and Obesity
- History of Hepatitis B
- History of Fatty Liver
- Pseudocanthosis Nigricans
- Rule Out (R/O) Coronary Artery Disease (CAD), Rule Out (R/O) Chronic Obstructive Pulmonary Disease (COPD)
Index Offences:
- The circumstances giving rise to the charges on the index offences are set out in last year’s Reasons for Disposition as follows:
“Ms. Isbister was charged with assaulting Monica Jubinville, a worker at the Shepherds of Good Hope and she is alleged to have breached conditions of a probation order issued in February 2004 after she was convicted of assault.
It is alleged that on March 26, 2004, Ms. Jubinville heard a scream coming from a lounge area at the Shepherds of Good Hope. On arrival, she found Ms. Isbister sitting with her head down and when questioned as to the reason for her screaming, she, for no apparent reason, grabbed Ms. Jubinville by the shirt and pushed her up against the wall after which she punched her all over her body, then grabbed Ms. Jubinville’s hair and pulled out clumps which caused her to fall to the floor. It is alleged that while Ms. Jubinville was on the floor, she was allegedly kicked repeatedly by Ms. I. The assault was interrupted after the arrival of another staff member in response to Ms. Jubinville having activated her emergency buzzer.
It is reported that the alleged victim suffered an abrased scalp, scratched and bruised hands as well as a sore back in addition to having had her hair pulled out.”
Criminal History
- Ms. Isbister’s criminal record dates back to 1989, when she was 20 years old, with her last recorded conviction occurring in 2008. Over this period, she accumulated a total of 24 convictions, most resulting in either non-custodial or brief custodial sentences. A significant portion of her record consists of violent offences, including assaulting a peace officer, assault with a weapon, and aggravated assault. Notably, her 2001 aggravated assault conviction resulted in a two-year term of imprisonment.
Background Information
The hospital report, dated September 24, 2025, provides a detailed account of Ms. Isbister’s history and background. It was filed as an exhibit and need not be repeated, but several details are of relevance.
Ms. Isbister was born in Prince Albert, Saskatchewan, and spent her early years living in both Saskatchewan and Alberta. Records indicate allegations of physical abuse by her stepfather and a family history of alcoholism. She has a younger half-brother who was diagnosed with paranoid schizophrenia and was hospitalized in Alberta. Previous attempts by mental health professionals to locate Ms. Isbister’s family members have been unsuccessful.
Ms. Isbister reported completing Grade 10 and has a limited employment history, including work in the food service industry and tree-planting in 1996. Earlier documentation suggests that she may have been involved in the sex trade at some point. She has primarily relied on social assistance and resided in shelters for several years preceding her 2004 index offence.
Records indicated that Ms. Isbister was briefly married, but the relationship ended due to physical abuse. Between 1985 and 1999, she gave birth to seven children, each fathered by a different man. All of her children were taken into state care and were either adopted or made permanent wards.
Ms. Isbister has not maintained contact with any family members since at least 2002, during which period she is reported to have led a transient lifestyle.
Ms. Isbister began using alcohol and drugs at the age of 14, including opioids, cocaine, marijuana, and hashish. She has stated that alcohol, particularly distilled spirits, was her primary substance of concern, as it often led to aggression and blackouts.
Psychiatric Background
Ms. Isbister’s psychiatric history dates back to at least 1992, when she was first hospitalized in Edmonton. Over the next four years, she was admitted seven times and diagnosed with bipolar disorder. Several hospitalizations were court-ordered for assessment purposes. During various admissions, she was described as unmanageable and assaultive.
Psychological testing conducted in 1996 indicated the presence of antisocial, paranoid, and borderline personality traits, as well as a tendency towards psychosis. Records note that Ms. Isbister typically improved while hospitalized but frequently became non-compliant with treatment after discharge.
In October 2003, Ms. Isbister was admitted to Thunder Bay Regional Hospital after being found swimming in Lake Superior. She explained that she had entered the lake to follow the “snake of the north”, believing it would lead her somewhere else.
Following several hospital transfers in 2004, her diagnosis was refined to schizoaffective disorder – bipolar type, alcohol and substance use disorder, and a manic episode that was only partially treated, with differential consideration for schizophrenia. These conditions were noted to exist against a background of borderline and antisocial personality traits.
At the time of her index offence, an assault on a female staff member, Ms. Isbister was residing at the Shepherds of Good Hope in Ottawa. Despite her repeated requests to return there, mental health professionals have consistently advised against it, noting that such a move would likely lead to renewed psychiatric destabilization.
Recent Course in Treatment
Ms. Isbister has been living at Le Manoir Caledonia in St. Isidore, Ontario, since June 10th, 2024. The residence is a 24-hour supervised group home where she has her own room, and all meals are provided. Staff provide assistance with room cleaning and laundry, and a personal support worker visits three times weekly to assist with bathing. Ms. Isbister is seen by a member of the outpatient team every two weeks. There have been no reported concerns regarding substance use (other than cigarette smoking), medication non-compliance, aggression, or attempts to leave the facility.
Throughout the reporting period, Ms. Isbister experienced occasional fluctuations in her mental health. On November 4, 2024, staff reported that she had not slept the previous night and was expressing delusional thoughts. During a virtual assessment that same day, Ms. Isbister stated that she believed she was pregnant and referred to a biblical figure she claimed to know but could not name. She was administered a PRN dose of Seroquel to assist with sleep. By the following day, her sleep had improved, and she no longer reported delusional thinking.
On June 10, 2025, during an in-person assessment, Ms. Isbister stated that she was enjoying life at the group home but expressed a wish to move to the Shepherds of Good Hope. She was reminded that the facility is a shelter and not suitable for her needs. Ms. Isbister appeared dismissive of concerns related to her prior assault on a staff member at that location. During the interview, she also reported hearing voices. Staff noted that she had been somewhat more irritable than usual but had not displayed any behaviours that raised safety concerns. With the consent of her substitute decision-maker, her Clozapine dosage was increased from 250 mg to 275 mg.
When reassessed on June 26, 2025, Ms. Isbister downplayed her earlier reports of auditory hallucinations, stating that she had only heard voices twice and had told them to “shut up.” She denied any desire to leave the facility at that time. However, during a later team conference, she again inquired about moving to the Shepherds of Good Hope.
On August 19, 2025, during a team conference, Ms. Isbister reiterated her request to return to the Shepherds of Good Hope. She renewed this request on September 24, 2025, and again in an interview with Dr. Linthorst shortly before the hearing.
Notwithstanding periodic fluctuations in her mental state, Ms. Isbister’s symptoms have consistently resolved quickly, and no safety concerns have arisen. Overall, she has demonstrated stability and positive adjustment throughout this reporting period.
Evidence at the Hearing:
The Board heard direct testimony from the current attending physician, Dr. R. Linthorst. Dr. Linthorst is a recent addition to the forensic treatment unit at the Brockville Mental Health Centre (BMHC). Although he was not the author of the hospital report, he adopted its contents and confirmed that he had met personally with Ms. Linthorst prior to the hearing.
Dr. Linthorst testified that Ms. Isbister presents as a low risk of violence while residing at Le Manoir Caledonia and under the supervision of the Ontario Review Board. Her protective factors include medication compliance and sustained abstinence from alcohol and drugs. Importantly, there has been no evidence of aggression for several years.
Dr. Linthorst further stated that without the structure and support provided by the ORB and supervised housing, Ms. Isbister’s risk level would likely increase to moderate.
He confirmed that Ms. Isbister suffers from a chronic psychotic illness that has historically been exacerbated by substance use. In his opinion, any relapse into substance use would result in rapid and significant mental deterioration.
During the reporting year, Ms. Isbister demonstrated relative stability, with only two brief and minor exacerbations of psychotic symptoms. Her medication regimen was slightly adjusted to address these concerns. Of ongoing concern are her repeated requests to return to the Shepherds of Good Hope, the location of her index offence, despite repeated education regarding the unsuitability and risk associated with that environment.
Responding to Mr. Davies’s questions, Dr. Linthorst confirmed that the lines of communication between the forensic team and Le Manoir Caledonia are excellent. Should there be a change in Ms. Isbister’s presentation, he is confident that the staff at Le Manoir Caledonia would promptly bring it to the attention of the team.
Dr. Linthorst also agreed with Mr. Davies’s suggestion that, although Ms. Isbister has not recently attempted elopement, given her past history and her expressed wish to live at the Shepherds of Good Hope, it would be prudent to include in the Disposition a clause pursuant to s. 672.92(1) of the Criminal Code, authorizing a police officer to arrest and return her to hospital in the event of a breach, or anticipated breach, of the Disposition.
The treatment team is also considering the introduction of additional supports, including the possibility of cognitive behavioural therapy (CBT) or other psychotherapeutic interventions for psychosis, although the availability of such programs at the hospital is quite limited. Nonetheless, Dr. Linthorst indicated that he would discuss some options with her.
No further evidence was presented.
Current Violent Risk Assessment
Dr. Eshter Carefoot recently conducted a structured risk assessment using the HCR-20 Version 3 (HCR-20-v3) tool. A detailed analysis of this assessment appears on pages 77–78 of the hospital report. It was noted that Ms. Isbister’s static risk factors remain largely unchanged from previous evaluations. She has a longstanding history of multiple assaults, including the index offence, as well as assaults on individuals in shelters, nursing staff in hospital settings (both prior to and following her detention under the jurisdiction of the Ontario Review Board), and on peers.
Dr. Carefoot concluded that Ms. Isbister continues to pose a significant risk to public safety. The following passages appear on page 78 of the hospital report:
With respect to future risk management Ms. Isbister will continue to require assistance with professional services and plans, living situation, personal support, treatment or supervision response and stress and coping. Currently these concerns are being managed by the outpatient team in collaboration with group home staff at Caledonia Manor. However, without these supports it is likely that Ms. Isbister would struggle in all of these areas resulting in an increased level of risk. Ms. lsbister's current residence is essential in managing her risk in the community. The group home supervises administration of medication, arranging of blood work for her medications, activities of daily living and monitoring of symptoms on a day-day basis. With the support of the group home and the outpatient team Ms. lsbister's risk of future violence is low as is her risk of serious physical harm and imminent violence. However, without the support of the group home and outpatient team her risk is likely to increase to moderate for future violence and serious physical harm.
HOSPITAL RECOMMENDATIONS
The hospital is of the opinion Ms. Isbister continues to present a significant risk to the safety of the public but collaboration between the outpatient team and the group home sufficiently manages her risk factors such that she is able to live in the community with a low level of risk. The hospital is also of the opinion that a conditional discharge with the provision that Ms. Isbister continue to reside at Le Manoir Caledonia and continues to refrain from substance use is the most appropriate and least onerous, least restrictive means by which to manage her level of risk. The hospital is requesting Le Manoir Caledonia be identified as Ms. lsbister's community residence as support from this group home is essential to her ability to successfully reside in the community. Ms. Isbister does not appreciate the role of her current residence in reducing her level of risk while residing in the community. She continues to express a desire to return to a temporary shelter, Shepherds of Good Hope despite education provided. Therefore, given Ms. lsbister's history of elopements the hospital is of the opinion that including this requirement in her disposition is needed in order to safely transition Ms. Isbister to a conditional discharge.”
Conclusions and Disposition
Based on the evidence and parties’ joint submissions, the Board unanimously concludes that Ms. Isbister continues to present a significant threat to public safety. This conclusion is supported by her lengthy behavioural and criminal history, her chronic mental illness, and her ongoing need for structured supervision and treatment. The issue of significant threat was neither raised nor contested by the parties.
Ms. Isbister’s insight into her mental illness, her need for medication, and her potential risk for violence remains limited. She continues to experience intermittent breakthrough symptoms and persists in expressing a desire to return to Shepherds of Good Hope, demonstrating little understanding of why such an environment would elevate her risk of psychiatric destabilization and violence.
To manage the identified risks, the Board determines that the least onerous and least restrictive disposition is a conditional discharge requiring Ms. Isbister to continue residing at Le Manoir Caledonia. The Board is encouraged by Ms. Isbister’s positive adjustment to her current placement and by the hospital’s ongoing collaboration with group home staff to ensure consistent monitoring and treatment. The Board also accepts Mr. Davies’ recommendation to include a clause, pursuant to s. 672.92(1) of the Criminal Code, authorizing a police officer to arrest and return Ms. Isbister to the hospital in the event of a breach, or anticipated breach, of the Disposition.
For these reasons, having regard to the paramount need to protect public safety, balanced with the patient’s mental condition, reintegration, and other needs, the Board orders a Conditional Discharge. The specific terms and conditions are set out in the accompanying Disposition.
DATED this 25th day of November, 2025, at the City of Toronto, in the Toronto Region.
Ms. L. Silver
Alternate Chairperson
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Office of the Registrar
Ontario Review Board