NCT03601026

Brief Summary

Severe mental illness (SMI) refers to the most burdensome psychiatric conditions. The need to pre-empt the onset of SMI is pressing because once SMI develops, quality of life is poor and available treatments have limited efficacy. Most risk factors for SMI are either unchangeable (e.g., genetics) or difficult to alter (e.g., low socio-economic status). In contrast, cannabis use is one specific risk factor that could be avoided. Certain individuals are more vulnerable to the harmful effects of cannabis. Genetic factors can help us identify these high-risk individuals. One in three individuals are carriers of a higher-risk genetic variant, and cannabis users with this genotype are at up to 7-fold increased risk of developing schizophrenia. In our study, genetic counselling will be provided to participants by a board-certified genetic counsellor. During the genetic counselling session, participants will have the option to receive their genotype. Participants will be counselled regarding their individualized risk of developing and of not developing SMI based on family history, whether or not they choose to use cannabis, and genotype (if the participants accept the genetic test results). The investigators hypothesize that this intervention will reduce exposure to cannabis compared to the youth who are not offered the intervention.

Trial Health

77
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
120

participants targeted

Target at P50-P75 for not_applicable

Timeline
16mo left

Started Nov 2019

Longer than P75 for not_applicable

Geographic Reach
1 country

1 active site

Status
recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

Study Progress83%
Nov 2019Sep 2027

First Submitted

Initial submission to the registry

July 5, 2018

Completed
21 days until next milestone

First Posted

Study publicly available on registry

July 26, 2018

Completed
1.3 years until next milestone

Study Start

First participant enrolled

November 1, 2019

Completed
6.8 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

September 1, 2026

Expected
1 year until next milestone

Study Completion

Last participant's last visit for all outcomes

September 1, 2027

Last Updated

May 14, 2025

Status Verified

May 1, 2025

Enrollment Period

6.8 years

First QC Date

July 5, 2018

Last Update Submit

May 13, 2025

Conditions

Mental IllnessSchizophreniaBipolar DisorderMajor Depressive DisorderCannabis UsePsychosis

Keywords

Severe mental illnessDevelopmental psychopathologyTrial-within-cohortGenetic counsellingCannabis usePrevention

Outcome Measures

Primary Outcomes (1)

  • Self-reported cannabis use

    Self-reported cannabis use on a questionnaire.

    1 month

Secondary Outcomes (2)

  • The proportion of participants who complete the intervention after receiving an offer to participate (intervention acceptability)

    Completion of study (2 years).

  • Presence of cannabinoids in urine

    1 month

Study Arms (2)

Genetic counselling

EXPERIMENTAL

Eligible participants who are randomized will be contacted and offered an invitation to attend the intervention. Genetic counselling will be provided to participants who accept the intervention as a single 1-2 hour session by a board-certified genetic counsellor. During the genetic counselling session, participants will have the option to receive their genotype at rs2494732. Participants will be counselled regarding their individualized risk of developing and of NOT developing SMI based on family history, whether or not they choose to use cannabis, and genotype (if they accept the genetic test results). Approximately 1 month after the intervention, participants will receive a follow-up interview.

Behavioral: Genetic counselling

Control group

NO INTERVENTION

Eligible participants who are not randomized to be offered the intervention will continue with their annual assessments as part of the parent study. These participants will receive the current standard of care (no intervention), and will not be offered or informed of the intervention.

Interventions

Genetic counsellingBEHAVIORAL

Participants will receive information on risk/protective factors and causes of mental illness. Participants are not required to receive numeric/genetic risk information. Participants who choose to receive genetic and/or numeric risk information will be counselled on their risk of NOT developing and of developing SMI based on their genetic test results and/or family history information they provide. Risk estimates will be derived by genetic counsellors, according to standard practice guidelines. Participants who receive genetic information will be counselled on the possible influence of cannabis use on risk of mental illness based on their genotype. Participants who choose to not receive genetic information will be counselled on the influence of cannabis on mental health.

Genetic counselling

Eligibility Criteria

Age12 Years - 21 Years
Sexall
Healthy VolunteersNo
Age GroupsChild (0-17), Adult (18-64)

You may qualify if:

  • Enrolment in the Families Overcoming Risks and Building Opportunities for Well-being (FORBOW) study.
  • Age between 12 and 21 years.
  • Knowledge of English sufficient to benefit from the intervention.
  • Capacity to provide informed consent at most recent FORBOW assessment.
  • Provision of consent to be contacted about future studies at most recent FORBOW assessment.

You may not qualify if:

  • A diagnosis of severe mental illness (psychotic disorder, bipolar disorder, severe/recurrent depression) at baseline
  • Autism or intellectual disability of a degree that interferes with assessment (IQ \< 70)

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Nova Scotia Health Authority

Halifax, Nova Scotia, B3H 2E2, Canada

RECRUITING

Related Publications (1)

  • Zwicker A, LeBlanc MA, Pavlova B, Alda M, Denovan-Wright EM, Uher R, Austin JC. Genetic counselling for the prevention of mental health consequences of cannabis use: A randomized controlled trial-within-cohort. Early Interv Psychiatry. 2021 Oct;15(5):1306-1314. doi: 10.1111/eip.13082. Epub 2020 Nov 26.

    PMID: 33242924DERIVED

Related Links

MeSH Terms

Conditions

Mental DisordersSchizophreniaBipolar DisorderDepressive Disorder, MajorPsychotic Disorders

Interventions

Genetic Counseling

Condition Hierarchy (Ancestors)

Schizophrenia Spectrum and Other Psychotic DisordersBipolar and Related DisordersMood DisordersDepressive Disorder

Intervention Hierarchy (Ancestors)

Genetic ServicesHealth ServicesHealth Care Facilities Workforce and Services

Study Officials

  • Rudolf Uher, MD, PhD

    Nova Scotia Health Authority, Dalhousie University

    PRINCIPAL INVESTIGATOR

Central Study Contacts

Rudolf Uher, MD, PhD

CONTACT

902-473-7209uher@dal.ca

Jill M Cumby, RN, MN

CONTACT

902-473-1781Jill.Cumby@nshealth.ca

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
SINGLE
Who Masked
OUTCOMES ASSESSOR
Masking Details
Eligible participants who are randomized to not be offered the intervention will not be aware of the presence of a potential intervention. Study staff who are assessing outcomes (i.e., psychopathology, cannabis use) will not know who did and did not receive the intervention.
Purpose
PREVENTION
Intervention Model
PARALLEL
Model Details: Trial-within-cohort
Sponsor Type
OTHER
Responsible Party
SPONSOR

Study Record Dates

First Submitted

July 5, 2018

First Posted

July 26, 2018

Study Start

November 1, 2019

Primary Completion (Estimated)

September 1, 2026

Study Completion (Estimated)

September 1, 2027

Last Updated

May 14, 2025

Record last verified: 2025-05

Data Sharing

IPD Sharing
Will not share

Locations

CA(1)