University of Oulu

Meyer-Rochow, V.B., Hakko, T., Hakko, H. et al. Synodic lunar phases and suicide: based on 2605 suicides over 23 years, a full moon peak is apparent in premenopausal women from northern Finland. Mol Psychiatry 26, 5071–5078 (2021).

Synodic lunar phases and suicide : based on 2605 suicides over 23 years, a full moon peak is apparent in premenopausal women from northern Finland

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Author: Meyer-Rochow, Victor Benno1,2; Hakko, Tapani3,4; Hakko, Helinä3;
Organizations: 1Department of Plant Medicals, Agricultural Science and Technology Institute, Andong National University, Andong, 36729, Republic of Korea
2Department of Ecology and Genetics, University of Oulu, Oulu, Finland
3Department of Psychiatry, Oulu University Hospital, Oulu, Finland
4Research Unit of Clinical 0Neuroscience, Psychiatry, Oulu, Finland
5Center for Life Course Health Research, University of Oulu, Oulu, Finland
6Unit of General Practice, Oulu University Hospital, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.7 MB)
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Language: English
Published: Springer Nature, 2021
Publish Date: 2021-05-03


Suicide data for this study were available for the period of March 1988 to June 2011, and involved 2111 male and 494 female victims from the Finnish province of Oulu. Data for lunar phases during that period were categorised into three groups: new moon (<25% visible), full moon (>75% visible) and other times with values in between. Seasonal effects were controlled with definitions for winter (Nov, Dec, Jan), spring (Feb, Mar, Apr), summer (May, June, July), and autumn (Aug, Sep, Oct). Suicide occurrences during different lunar phases were compared with their expected distribution using multinomial tests with all tests being two-tailed. Statistical significance was set at p < 0.05. No correlation between suicides and moon phase in any of the four seasons was apparent for male victims, but in winter for women it was (p = 0.001). Further analysis of the data revealed that the full moon association was statistically significant only for premenopausal women, defined as female victims younger than 45 years of age. To explain this unexpected finding a number of factors were considered, e.g., the darkness of a northern Finnish winter with increases of SAD and depression especially in premenopausal women, the influence of the lunar periodicity on the menstrual cycle, and cosmogeophysical effects on the humoral and autonomous nervous system.

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Series: Molecular psychiatry
ISSN: 1359-4184
ISSN-E: 1476-5578
ISSN-L: 1359-4184
Volume: 26
Pages: 5071 - 5078
DOI: 10.1038/s41380-020-0768-7
Type of Publication: A1 Journal article – refereed
Field of Science: 3124 Neurology and psychiatry
Funding: Financial support for VBM-R to complete this work came from Prof. Chuleui JUNG of Andong National University’s Basic Science Research Programme through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2018R1A6A1A03024862).
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