INTERPRETATION A single THC administration induces psychotic , negative , and other psychiatric symptoms with large effect sizes .
There is no consistent evidence that CBD induces symptoms or moderates the effects of THC .
BACKGROUND Approximately 188 million people use cannabis yearly worldwide , and it has recently been legalised in 11 US states , Canada , and Uruguay for recreational use .
The potential for increased cannabis use highlights the need to better underst and its risks , including the acute induction of psychotic and other psychiatric symptoms .
We aim ed to investigate the effect of the cannabis constituent Δ9-tetrahydrocannabinol ( THC ) alone and in combination with cannabidiol ( CBD ) compared with placebo on psychiatric symptoms in healthy people .
Does intravenous Δ9-tetrahydrocannabinol increase dopamine release? A SPET study
Intravenous ( IV ) Δ9-tetrahydrocannabinol ( THC ) induces transient psychotic symptoms in healthy subjects and in schizophrenic patients , but the psychotomimetic mechanism is unknown . One possibility is that THC stimulates dopamine ( DA ) release in the striatum . In this study we tested whether IV THC led to an increase in striatal DA release compared to placebo . We also investigated whether DA release and positive psychotic symptoms were related . Eleven healthy male volunteers completed two 123I-iodobenzamide ( [123I]IBZM ) single photon emission tomography ( SPET ) sessions and received IV THC ( 2.5 mg ) or placebo in a r and omized counterbalanced order , under double-blind conditions . Analysable data were obtained from nine participants . The Positive and Negative Syndrome Scale ( PANSS ) was used to rate psychotomimetic effects . Striatal binding index values were calculated using the occipital cortex as a reference region . Both the PANSS positive and general symptoms increased significantly at 30 min following IV THC . There were no significant differences in binding index in the cau date or putamen under THC compared to placebo conditions . Positive psychotic symptoms and DA release were unrelated . THC did not lead to a significant increase in DA release even though the dose was sufficient for participants to have psychotic symptoms . These findings do not support a central role for striatal DA in THC-elicited psychosis
INTERPRETATION A single THC administration induces psychotic , negative , and other psychiatric symptoms with large effect sizes .
There is no consistent evidence that CBD induces symptoms or moderates the effects of THC .
BACKGROUND Approximately 188 million people use cannabis yearly worldwide , and it has recently been legalised in 11 US states , Canada , and Uruguay for recreational use .
The potential for increased cannabis use highlights the need to better underst and its risks , including the acute induction of psychotic and other psychiatric symptoms .
We aim ed to investigate the effect of the cannabis constituent Δ9-tetrahydrocannabinol ( THC ) alone and in combination with cannabidiol ( CBD ) compared with placebo on psychiatric symptoms in healthy people .