Early LSD treatment in Denmark from 1960 to 1974: An analysis of possible and long-lasting changes in the adult personality following psychedelic treatment. A historical retrospective cohort study.
Medicine June 11, 2021 DOI: 10.1097/md.0000000000026300 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Historical cohort analysis Peer reviewed |
|---|---|
| Sample size | 151 |
| Population | Danish psychiatric patients treated with LSD from 1960 to 1974 |
| Intervention | Lysergic acid diethylamide (LSD) |
| Topics | LSD |
| Key findings | Analysis did not reveal personality changes such as "connectedness," but lasting personality changes were observed in 2 to 4 patients, and unwanted effects persisted for weeks or months following acute treatment in quite a few patients. |
Abstract
In view of the renewed interest in psychedelics in psychiatry it is timely to analyze psychedelic treatment in historical cohorts. Recently the therapeutic efficacy of psychedelics has been linked to the so-called phenomenon of "connectedness." The aim of the present study was to explore whether long-lasting personality changes were observed in any of the 151 Danish psychiatric patients who were treated with Lysergic acid diethylamide (LSD) from 1960 to 1974.The exploration included a reanalysis of a subgroup as well from a 1964 Danish historical cohort. Medical records and other case materials of the above mentioned 151 patients are kept in the Danish State Archives. The present author was granted access to the LSD case materials in the Danish State Archives, and respected confidentiality per the Archives Law. According to the LSD Damages Law from 1986, they all received financial compensation for LSD-inflicted harm.Analysis did not reveal any personality changes such as "connectedness;" however, other lasting personality changes were observed in 2 to 4 patients and in quite a few patients unwanted effects persisted for weeks or months following acute treatment. In the present analysis of the 1964 cohort, the same percentage of patients improved with LSD treatment as in the historical analysis. In the latter, however, little attention was given to side effects, such as suicide attempts, suicides, and one homicide.Future psychedelic research with psychiatric patients should respect the potential toxicity of LSD and other psychedelics and meticulously monitor possible side effects.
Comparable studies
Other observational and cohort studies on LSD, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Increased Global Functional Connectivity Correlates with LSD-Induced Ego Dissolution. Human participants | 2016 | Observational cohort | |
| Increased spontaneous MEG signal diversity for psychoactive doses of ketamine, LSD and psilocybin Humans | 2017 | Observational study | |
| Classic psychedelic use is associated with reduced psychological distress and suicidality in the United States adult population. USA adult respondents from the National Survey on Drug Use and Health (2008-2012) | 2015 | Observational cohort | n = 190,000 |
| Psychedelics not linked to mental health problems or suicidal behavior: A population study Randomly selected United States adults | 2015 | Observational cohort | n = 135,095 |
| Whole-Brain Multimodal Neuroimaging Model Using Serotonin Receptor Maps Explains Non-linear Functional Effects of LSD. Healthy human participants | 2018 | Observational study with computational modeling |
Citations in the library
Cited by 5
- Risk of bias in randomized clinical trials on psychedelic medicine: A systematic review Journal of Psychopharmacology July 1, 2023
- Animal Behavior in Psychedelic Research. Pharmacological Reviews October 1, 2022
- Beyond Psilocybin: Reviewing the Therapeutic Potential of Other Serotonergic Psychedelics in Mental and Substance Use Disorders Journal of Psychoactive Drugs August 24, 2023
- Uso de psicodélicos para tratamento de transtornos psiquiátricos: uma revisão integrativa Bionorte October 22, 2024
- Treatment with LSD and psilocybin at the department of psychiatry at Frederiksberg Hospital in Denmark from 1960 to 1973: an analysis of 324 cases Nordic Journal of Psychiatry July 10, 2025
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