THC Titration of High-Potency Cannabis Concentrates

Inclusion Criteria: * Age 19-55 years. * Frequency of primary exposure to cannabis 1-4 occasions per week, through any route of administration, over the past three months; participants must report experience with vaping high-potency liquid concentrates with more than 3 exposures to 90% THC and willingness to use such products in the study. * Refrain from cannabis for 48 hours and from alcohol for 12 hours before visits. * Agree not to drive a car for 24 hours after each visit. * Abstain from recreational drugs for at least 48 hours prior to each visit. * Abstain from any drugs not medically required. * Well-controlled blood pressure for participants with hypertension. Exclusion Criteria: * Pregnant/breastfeeding (women of childbearing potential must have a negative pregnancy test and report use of appropriate contraception). * Evidence of cardiac arrhythmias/failure, ischaemic heart disease. * Recent open heart/open chest surgery or cataract surgery. * Evidence from Structured Clinical Interview for DSM-5 \[SCID-5-CT\] or clinical evaluation of lifetime psychotic disorder/schizophrenia or bipolar disorder; family history of a first-degree relative with a diagnosis of psychotic disorder or schizophrenia; history of psychiatric co-morbidities in the past year (major depression, anxiety disorder or suicide attempt in past year or current suicidal ideation) and current substance use disorder/dependence. * Evidence of neurological illness (e.g., stroke, epilepsy, traumatic brain injury). * Renal or hepatic abnormalities (self-report and blood hematology/chemistry); and * Respiratory diseases, including asthma and physician-diagnosed lung disease. * Taking prescribed medications that contain either THC or cannabidiol (CBD). * Participation in another clinical or non-therapeutic study in the last three months. * Bleeding disorders.