Decreased mental time travel to the past correlates with default-mode network disintegration under lysergic acid diethylamide
Jana Speth, Clemens Speth, Mendel Kaelen, Astrid M Schloerscheidt, Amanda Feilding, David J Nutt, Robin L Carhart-Harris
Journal of Psychopharmacology January 1, 2016 DOI: 10.1177/0269881116628430 via CORE
Summary
AI-generated from the abstractA single dose of LSD (75 μg) reduced how often people spontaneously thought about the past, while thoughts about the present or future remained unchanged. In a placebo-controlled crossover study with 20 healthy volunteers, fewer references to past mental spaces appeared in reports collected about 2.5 hours after intravenous administration. This reduction correlated with the drug's subjective intensity and with decreased resting-state functional connectivity within the default-mode network, a brain system involved in autobiographical memory and rumination. The findings suggest LSD may reduce past-focused thinking, which could be relevant for treating conditions like depression where excessive reflection on the past is common.
Study at a glance
| Characteristics | Randomized controlled crossover trial Placebo-controlled Peer reviewed |
|---|---|
| Sample size | 20 |
| Population | Healthy volunteers |
| Intervention | LSD |
| Dose | 75 μg |
| Duration | Approximately 2.5 h post-administration |
| Keywords | Mental health Psychiatry Psychology Cognitive health Emotional well-being |
| Citations | 119 |
| Key finding | LSD significantly reduced mental time travel to the past, and this effect correlated with decreased default-mode network connectivity. |
Abstract
This paper reports on the effects of LSD on mental time travel during spontaneous mentation. Twenty healthy volunteers participated in a placebo-controlled crossover study, incorporating intravenous administration of LSD (75 μg) and placebo (saline) prior to functional magnetic resonance imaging (fMRI). Six independent, blind judges analysed mentation reports acquired during structured interviews performed shortly after the functional magnetic resonance imaging (fMRI) scans (approximately 2.5 h post-administration). Within each report, specific linguistic references to mental spaces for the past, present and future were identified. Results revealed significantly fewer mental spaces for the past under LSD and this effect correlated with the general intensity of the drug’s subjective effects. No differences in the number of mental spaces for the present or future were observed. Consistent with the previously proposed role of the default-mode network (DMN) in autobiographical memory recollection and ruminative thought, decreased resting-state functional connectivity (RSFC) within the DMN correlated with decreased mental time travel to the past. These results are discussed in relation to potential therapeutic applications of LSD and related psychedelics, e.g. in the treatment of depression, for which excessive reflection on one’s past, likely mediated by DMN functioning, is symptomatic