Plain English Summary

Lay summary under review 2

Trial website

Contact information

Type

Scientific

Primary contact

Dr Nadia Solowij

ORCID ID

Contact details

School of Psychology
University of Wollongong
Wollongong
2522
Australia
nadia@uow.edu.au

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

CT12/003

Study information

Scientific title

Vulnerability markers in the association between cannabis and schizophrenia: a randomised controlled trial of acute cannabinoid administration

Acronym

Study hypothesis

The acute administration of cannabinoids (THC + CBD) will modulate the amplitude of the mismatch negativity (a brain marker of glutamate receptor function) in regular cannabis users versus non-naïve controls.

Ethics approval

Joint University of Wollongong and Illawarra and Shoalhaven Local Health Network Health and Medical Human Research Ethics committee, 6 August 2012, Reference number: CT12/003

Study design

Randomised double-blind placebo-controlled crossover study

Primary study design

Interventional

Secondary study design

Randomised controlled trial

Trial setting

Other

Trial type

Treatment

Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet

Condition

Cannabis use and psychosis

Intervention

Cannabis user and non-user non-naïve control participants will receive each of the following five conditions in randomised order, administered through a vaporiser

1. Tetrahydrocannabinol (THC) alone
2. Cannabidiol (CBD) alone (high dose)
3. THC+ CBD (low dose)
4. THC + CBD (high dose)
5. Placebo

Intervention type

Other

Phase

Not Applicable

Drug names

Primary outcome measures

The effect of THC and CBD on MMN amplitude recorded immediately following drug administration

Secondary outcome measures

The effect of THC and CBD on
1. Other EEG/ERP measures including P50 and resting state EEG
2. Neuropsychological measures including CogState battery of tests
3. Psychotic-like symptoms as indicated on a visual analogue scale, the Psychotomimetic States Inventory and the Clinician Administered Dissociative States Scale.
4. The potential moderating effect of specific genetic polymorphisms on THC and CBD (alone and in combination) effects on the MMN and other EEG/ERP and neuropsychological measures.

Overall trial start date

12/11/2012

Overall trial end date

31/03/2014

Reason abandoned

Eligibility

Participant inclusion criteria

Cannabis user group
1. Cannabis use for at least 3 years, and at least 4 times a month.
2. All participants must be between 18 and 55 years of age.

Control group
1. Cannabis use at least 5 times but less than 20 times in total across lifetime; and for those participants only having used 5-10 times, they must have used at least once in the last 2 years; while for those participants having used between 10 and 20 times, the most recent exposure must not have been more than 10 years ago. No cannabis use in the past 3 months.
2. All participants must be between 18 and 55 years of age.

Participant type

Patient

Age group

Adult

Gender

Both

Target number of participants

40

Participant exclusion criteria

Cannabis user group
1. Daily cannabis use, or use of any illicit substance more than once a month for a period of six months
2. Head injury resulting in trauma to the brain, prolonged unconsciousness or concussion or required surgery, prolonged hospitalisation or rehabilitation
3. Medical diagnosis that would interfere with EEG testing (epilepsy, stroke, brain tumour, HIV positive, Hepatitis B or C, meningitis, encephalitis, MS, microcephaly), or a medical diagnosis contraindicated for cannabis exposure (e.g. asthma, cardiovascular disease, untreated hypertension).
4. Co-ingestion / concurrent use of medicines or drugs which will interfere with testing or are contraindicated for cannabis exposure (e.g. antipsychotics, antidepressants, benzodiazepines, amphetamines, opioids, alcohol).
5. A Body Mass Index (BMI) of less than 18 kg/m2 or more than 28 kg/m2.
6. A history of anaemia
7. Pregnancy
8. A current diagnosis of a psychotic disorder, or a score of 50 or more on the Community Assessment of Psychic Experiences. A first degree family member with psychotic diagnosis.
9. Use of any illicit substance (other than cannabis) in the 14 days prior to testing.
10. Meets DSM-IV criteria for dependence on alcohol or drugs other than cannabis; history of treatment for substance use problems other than cannabis.

Control group
1. Use of any illicit substance more than once a month for a period of six months.
2. Head injury resulting in trauma to the brain, prolonged unconsciousness or concussion or required surgery, prolonged hospitalisation or rehabilitation.
3. Medical diagnosis that would interfere with EEG testing (epilepsy, stroke, brain tumour, HIV positive, Hepatitis B or C, meningitis, encephalitis, MS, microcephaly), or a medical diagnosis contraindicated for cannabis exposure (e.g. asthma, cardiovascular disease, untreated hypertension).
4. Co-ingestion /concurrent use of medicines or drugs which will interfere with testing or are contraindicated for cannabis exposure (e.g. antipsychotics, antidepressants, benzodiazepines, amphetamines, opioids, alcohol).
5. A body Mass Index (BMI) of less than 18 kg/m2 or more than 28 kg/m2.
6. A history of anaemia.
7. Pregnancy
8. A current diagnosis of a psychotic disorder, or a score of 50 or more on the Community Assessment of Psychic Experiences.
9. A first degree family member with psychotic diagnosis. Use of any illicit substance (other than cannabis) in the 14 days prior to testing.
10. Meets DSM-IV criteria for dependence on alcohol or drugs or a history of treatment for substance use problems.

Recruitment start date

12/11/2012

Recruitment end date

31/03/2014

Locations

Countries of recruitment

Australia

Trial participating centre

School of Psychology
Wollongong
2522
Australia

Sponsor information

Organisation

University of Wollongong (Australia)

Sponsor details

Northfields Avenue
Wollongong
2522
Australia

Sponsor type

University/education

Website

Funders

Funder type

Research council

Funder name

National Health and Medical Research Council of Australia (NHMRC) (Australia) Project Grant ID: 1007593

Alternative name(s)

Funding Body Type

Funding Body Subtype

Location

Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

Publication citations

Editorial Notes