Factors influencing marijuana self-administration by humans

Area of Science:

• Neuroscience
• Psychopharmacology
• Behavioral Economics

Background:

• Understanding the reinforcing properties of tetrahydrocannabinol (THC) is crucial for addressing marijuana use.
• Investigating factors that influence self-administration of marijuana, such as drug content and external rewards, is important for public health.
• Assessing the development of tolerance to both subjective and reinforcing effects of THC is key to understanding long-term use patterns.

Purpose of the Study:

• To determine if delta 9-THC content influences marijuana self-administration.
• To examine the impact of monetary incentives on marijuana choice behavior.
• To investigate the development of tolerance to the subjective and reinforcing effects of marijuana.

Main Methods:

• A 16-day residential study involving 12 marijuana users.
• Participants made repeated choices between marijuana cigarettes with varying THC concentrations (0.0, 2.2, 3.9%) and snack foods.
• A modified progressive ratio schedule was used for choice trials, with an optional monetary task introduced.

Main Results:

• Cigarettes with 2.2% and 3.9% THC were self-administered more frequently than placebo.
• The availability of monetary rewards influenced participants' decisions to delay marijuana consumption.
• Subjective ratings of 'high,' 'stimulated,' and 'good drug effect' decreased over the study period.

Conclusions:

• Delta 9-THC is an essential reinforcing component of marijuana.
• Monetary contingencies can effectively manipulate marijuana self-administration.
• Tolerance to subjective effects of marijuana may develop more rapidly than tolerance to its reinforcing effects.