Pilot Study: Effect of electrical brain stimulation on mental skills of individuals with long-term cannabis use

Not Applicable

• Conditions: Cognition; Neurological - Other neurological disorders

• Registration Number: ACTRN12619000462189
• Lead Sponsor: niversity of Tasmania

Brief Summary

Not available

Detailed Description

Not available

Study Timeline

• Results First Posted: 1900-01-01
• Study Start: 2019-03-20
• Study Completion: 2020-03-19
• Last Update Posted: 27 April 2020

Recruitment & Eligibility

• Status: Stopped early
• Sex: All
• Target Recruitment: 20

Inclusion Criteria

General inclusion criteria: 18-50 years old, male and female, English-speakers, normal or corrected-to-normal vision

Cannabis group inclusion criteria: Individuals who have regularly (1+ days per week) used cannabis for 1+ year. We are not specifically recruiting individuals with cannabis use disorder (CUD); however, participants may meet criteria for CUD. Cannabis users will be asked to refrain from cannabis use 24 hours + prior to the Research Session.

Control group: No history of cannabis use or minimal (<50 lifetime uses) history of cannabis use

Exclusion Criteria

General exclusion criteria:
• No current or recent illicit drug use (in the past 30 days)
• Dependence on alcohol (a dependency score of 20 or more on the Alcohol Use Disorder Identification Test) or other illicit substances, except nicotine
• Pregnancy or suspected pregnancy
• Known psychological problems (e.g., depression, anxiety, schizophrenia, PTSD); participants who self-report a clinical diagnosis will be excluded from the study,
• Physical conditions or problems (such as cardiac problems and using related medication such as beta-blockers)
• Metabolic diseases that would confound measures of metabolites (e.g., renal and kidney disease, phenylketonuria/PKU, tyrosinemia)
• Use of prescribed medications to treat psychological conditions (e.g., anxiolytics, antidepressants) due to the potential interactive effect between tDCS and particular medications that could affect measures of cortical excitability

Brain stimulation contraindications:
• Epilepsy or family history of epilepsy
• History of neuropsychiatric conditions (e.g., stroke)
• Skin compromised by pre-existing or current burns (e.g., sun burn), injuries, or conditions affecting the scalp (eczema or psoriasis on the head)
• Pre-existing implants such as pacemakers and metal implants (excluding dental work such as tooth fillings, dental implants and non-ferromagnetic material). Any implant that is conductive, ferromagnetic or contains other magnetic-sensitive metals such as cochlea implants, stents, or implanted stimulators are contraindicated for TMS
• Implanted electronic devices or intracranial magnetic clips such as aneurysm clips
• Serious head injury or neurosurgery

Study & Design

• Study Type: Interventional
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Cognitive functioning: Decision making, measured by the Iowa Gambling Task[Cognitive functioning (decision making) will be measured pre- and post- tDCS intervention];Cognitive functioning: Inhibitory control, measured by the Go/No-Go Task[Cognitive functioning (inhibitory control) will be measured pre- and post- tDCS intervention]

Secondary Outcome Measures

Name	Time	Method
Composite secondary outcome - Urinary amino acid biomarkers: <br>1. Gamma y-aminobutyric acid <br>2. L-glutamine<br>3. Succinic acid<br>4. Alpha-ketoglutaric acid<br>5. Catecholaminergic (norepinephrine, epinephrine)<br>6. Dopamine<br>7. D,L-tryptophan<br>8. L-tyrosine<br>9. p-tyramine<br>10. Serotonergic<br>11. L-kynurenine<br>12. L-ornithine<br><br>[Urine samples will be obtained pre- and post- tDCS intervention]