TY  - JOUR
PY  - 2018//
TI  - Previous cannabis exposure modulates the acute effects of delta-9-tetrahydrocannabinol on attentional salience and fear processing
JO  - Experimental and clinical psychopharmacology
A1  - Colizzi, Marco
A1  - McGuire, Philip
A1  - Giampietro, Vincent
A1  - Williams, Steve
A1  - Brammer, Mick
A1  - Bhattacharyya, Sagnik
SP  - 582
EP  - 598
VL  - 26
IS  - 6
N2  - Cannabis can induce transient psychotic and anxiety symptoms and long-lasting disorders. The acute psychoactive effects of its main active ingredient, (-)-trans-Δ9-tetrahydrocannabinol (Δ9-THC), may be modulated by previous cannabis exposure. Secondary data analyses tested whether modest previous cannabis exposure modulated the acute effects of Δ9-THC on attentional salience and emotional processing and their neurophysiological substrates. Twenty-four healthy men participated in a double-blind, randomized, placebo-controlled, repeated-measures, within-subject, Δ9-THC challenge study using fMRI. Compared with nonusers (NUs; n = 12; <5 lifetime cannabis joints smoked), abstinent-modest cannabis users (CUs; n = 12; 24.5 ± 9 lifetime cannabis joints smoked) showed less efficient attentional salience processing and recruited different/additional brain areas to process attentional salient and emotional stimuli (all ps ≤.01). The Δ9-THC challenge disrupted attentional salience and emotional-processing-related brain activity and induced transient anxiety and psychotic symptoms (all ps ≤.02). However, Δ9-THC-induced psychotic symptoms and attentional salience behavioral impairment were more pronounced in NUs compared with CUs (all ps ≤.04). Also, NUs under Δ9-THC shifted toward recruitment of other brain areas to perform the tasks. Conversely, CUs were less affected by the acute challenge in an exposure-dependent manner, showing a neurophysiological pattern similar to that of NUs under placebo. Only in NUs, Δ9-THC-induced psychotic symptom and cognitive impairment severity was associated with a more pronounced neurophysiological alteration (all ps ≤.048). In conclusion, CUs displayed residual effects of cannabis exposure but more blunted responses to the acute symptomatic, behavioral, and neurophysiological effects of Δ9-THC, which were more marked in NUs. (PsycINFO Database Record<br><br>(c) 2018 APA, all rights reserved).<p />  <p>Language: en</p>
LA  - en
SN  - 1064-1297
UR  - http://dx.doi.org/10.1037/pha0000221
ID  - ref1
ER  -