Changes in human event related potentials with prolonged delta-9-tetrahydrocannabinol (THC) use

Area of Science:

• Neuroscience
• Psychopharmacology
• Cognitive Psychology

Background:

• Tetrahydrocannabinol (THC) is a psychoactive compound in marijuana with known cognitive effects.
• Auditory event related potentials (AERP) and contingent negative variation (CNV) are electrophysiological measures sensitive to attention and cognitive processing.

Purpose of the Study:

• To investigate the effects of chronic THC intoxication on AERP and CNV.
• To assess dose-dependent and time-dependent alterations in attentional processing during THC use.
• To explore potential lasting cognitive impacts in heavy marijuana users.

Main Methods:

• Recording of AERP and CNV in hospitalized volunteers undergoing controlled THC administration at two dose levels (70-90 mg/day or 180-210 mg/day).
• Testing occurred before, during (early and late phases), and after THC intoxication.
• A control group received no THC.

Main Results:

• Early high-dose THC (180-210 mg/day) administration depressed the N1 component of AERP.
• Contingent negative variation (CNV) was depressed during early THC exposure across tasks, except for a control task.
• Late in the THC period, CNV depression was observed only in the most difficult task at the higher THC dose.

Conclusions:

• THC intoxication induces alterations in attentional processing, reflected in changes to N1 and CNV.
• These attentional deficits may persist in heavy marijuana users, particularly in complex cognitive tasks.
• The findings suggest THC impacts stimulus processing and attention dynamically during chronic use.