Delta-9-tetrahydrocannabinol, neural oscillations above 20 Hz and induced acute psychosis

Nottage, JF, Stone, J, Murray, RM, Sumich, A ORCID: 0000-0003-4333-8442, Bramon-Bosch, E, ffytche, D and Morrison, PD, 2015. Delta-9-tetrahydrocannabinol, neural oscillations above 20 Hz and induced acute psychosis. Psychopharmacology, 232 (3), pp. 519-528. ISSN 0033-3158

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Rationale: An acute challenge with delta-9-tetrahydrocannabinol (THC) can induce psychotic symptoms including delusions. High electroencephalography (EEG) frequencies, above 20 Hz, have previously been implicated in psychosis and schizophrenia. Objectives: The objective of this study is to determine the effect of intravenous THC compared to placebo on high-frequency EEG. Methods: A double-blind cross-over study design was used. In the resting state, the high-beta to low-gamma magnitude (21–45 Hz) was investigated (n=13 pairs+4 THC only). Also, the event-related synchronisation (ERS) of motor-associated high gamma was studied using a self-paced button press task (n=15). Results: In the resting state, there was a significant condition × frequency interaction (p=0.00017), consisting of a shift towards higher frequencies under THC conditions (reduced high beta [21–27 Hz] and increased low gamma [27–45 Hz]). There was also a condition × frequency × location interaction (p=0.006), such that the reduction in 21–27-Hz magnitude tended to be more prominent in anterior regions, whilst posterior areas tended to show greater 27–45-Hz increases. This effect was correlated with positive symptoms, as assessed on the Positive and Negative Syndrome Scale (PANSS) (r=0.429, p=0.042). In the motor task, there was a main effect of THC to increase 65–130-Hz ERS (p=0.035) over contra-lateral sensorimotor areas, which was driven by increased magnitude in the higher, 85–130-Hz band (p=0.02) and not the 65–85-Hz band. Conclusions: The THC-induced shift to faster gamma oscillations may represent an over-activation of the cortex, possibly related to saliency misattribution in the delusional state.

Item Type: Journal article
Publication Title: Psychopharmacology
Creators: Nottage, J.F., Stone, J., Murray, R.M., Sumich, A., Bramon-Bosch, E., ffytche, D. and Morrison, P.D.
Publisher: Springer
Date: 2015
Volume: 232
Number: 3
ISSN: 0033-3158
Divisions: Schools > School of Social Sciences
Depositing User: Jonathan Gallacher
Date Added: 17 Oct 2016 16:01
Last Modified: 09 Jun 2017 14:07

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