OPEN Foundation

Day: 21 September 2017

Increased thalamic resting-state connectivity as a core driver of LSD-induced hallucinations

Abstract

OBJECTIVE:
It has been proposed that the thalamocortical system is an important site of action of hallucinogenic drugs and an essential component of the neural correlates of consciousness. Hallucinogenic drugs such as LSD can be used to induce profoundly altered states of consciousness, and it is thus of interest to test the effects of these drugs on this system.
METHOD:
100 μg LSD was administrated orally to 20 healthy participants prior to fMRI assessment. Whole brain thalamic functional connectivity was measured using ROI-to-ROI and ROI-to-voxel approaches. Correlation analyses were used to explore relationships between thalamic connectivity to regions involved in auditory and visual hallucinations and subjective ratings on auditory and visual drug effects.
RESULTS:
LSD caused significant alterations in all dimensions of the 5D-ASC scale and significantly increased thalamic functional connectivity to various cortical regions. Furthermore, LSD-induced functional connectivity measures between the thalamus and the right fusiform gyrus and insula correlated significantly with subjective auditory and visual drug effects.
CONCLUSION:
Hallucinogenic drug effects might be provoked by facilitations of cortical excitability via thalamocortical interactions. Our findings have implications for the understanding of the mechanism of action of hallucinogenic drugs and provide further insight into the role of the 5-HT2A -receptor in altered states of consciousness.
Mueller, F., Lenz, C., Dolder, P., Lang, U., Schmidt, A., Liechti, M., & Borgwardt, S. (2017). Increased thalamic resting‐state connectivity as a core driver of LSD‐induced hallucinations. Acta Psychiatrica Scandinavica. 10.1111/acps.12818
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Does psychedelic drug use reduce risk of suicidality? Evidence from a longitudinal community-based cohort of marginalised women in a Canadian setting

Abstract

OBJECTIVE:
This study aimed to longitudinally investigate whether ever having used a psychedelic drug can have a protective effect on incidence of suicidality among marginalised women.
DESIGN:
Longitudinal community-based cohort study.
SETTING:
Data were drawn from a prospective, community-based cohort of marginalised women in Metro Vancouver, Canada.
PARTICIPANTS:
766 women completed the baseline questionnaire between January 2010 and August 2014. Participants who did not report suicidality at baseline and who completed at least one follow-up visit were included.
MAIN OUTCOME MEASURE:
Extended Cox regression was used to model predictors of new suicidality (suicide ideation or attempts) over 54-month follow-up.
RESULTS:
Nearly half (46%; n=355) of participants reported prior suicidality and were thus excluded from the present analyses. Of 290 women eligible at baseline, 11% (n=31) reported recent suicidality during follow-up, with an incidence density of 4.42 per 100 person-years (95% CI 3.10 to 6.30). In multivariable analysis, reported lifetime psychedelic drug use was associated with a 60% reduced hazard for suicidality (adjusted HR (AHR) 0.40; 95% CI 0.17 to 0.94). Crystal methamphetamine use (AHR 3.25; 95% CI 1.47 to 7.21) and childhood abuse (AHR 3.54; 95% CI 1.49 to 8.40) remained independent predictors of suicidality.
CONCLUSION:
The high rate of suicidality identified in this study is of major concern. Alongside emerging evidence on the potential of psychedelic-assisted therapy to treat some mental illness and addiction issues, our findings demonstrate that naturalistic psychedelic drug use is independently associated with reduced suicidality, while other illicit drug use and childhood trauma predispose women to suicidality. While observational, this study supports calls for further investigation of the therapeutic utility of psychedelic drugs in treating poor mental health and promoting mental wellness.
Argento, E., Strathdee, S. A., Tupper, K., Braschel, M., Wood, E., & Shannon, K. (2017). Does psychedelic drug use reduce risk of suicidality? Evidence from a longitudinal community-based cohort of marginalised women in a Canadian setting. BMJ open7(9), e016025. 10.1136/bmjopen-2017-016025
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