Suicide by Lunar and Seasonal Factors

Introduction

In my work I noticed that lunar and seasonal factors were associated with demand for appointments, symptoms and symptom intensity reported across meetings, and relapse. In order to investigate the effects of lunar and seasonal factors on psychological distress, in 2011 I did a study of this subject using the dates of 43,645 suicides in England and Wales from 2001 to 2010. Due to other work demands I never finished preparing the study for publication. I have posted extracts from a draft write-up below, as I think the results are of potential interest to others. The results are consistent with what I had noticed in my work and I often referred to these results in order to help people understand and better manage their difficulties associated with these natural environment stressors.

Stress

The concept of homeostasis is central to the idea of stress. Most biochemical processes in biology strive to maintain equilibrium, which is more of an ideal steady state rather than an achievable condition. As internal and external environmental factors continually disrupt homeostasis, an organism’s condition wavers about a homeostatic point that is the organism’s optimal condition for living. Factors that cause an organism’s condition to waver away from homeostasis result in stress.¹ Neuroscientists of today emphasize the role of environmental demands (stressors) that exceed the natural regulatory capacity of an organism to cause stress.¹ Such stressors might include those of the moon and seasons. Further, stress can be described as either “eustress”, which is stress that is healthy or gives one positive feelings, or “distress”, the most commonly-referred to type of stress and which has negative implications.²

Stressful person-environment relationships can be thought of in terms of the relative balance of forces between environmental demands and the person’s psychological resources for dealing with them. A seesaw analogy can be used, with environmental load on one side of the fulcrum and the person’s resources on the other side. If the environmental load substantially exceeds the person’s resources, a stressful relationship exists. If the person’s resources are about equal to or exceed the demands, the situation is not stressful. A lack of involvement or stimulation can result in boredom or tedium, while excessive demands can result in feelings of panic, hopelessness and depression.³ Thus in human psychobiology it has been found that psychological stress results from both under-stimulation as well as over-stimulation.⁴

Suicide

Worldwide suicide rates have increased by 60 percent in the past 45 years, mainly in the developing countries. Suicide is now the tenth leading cause of death⁵ with about a million suicides annually, or a suicide every 40 seconds.⁶

Factors correlated with suicide risk include underlying mental disorder, drug addiction, availability of means, family history of suicide, previous head injury,⁷ socio-economic factors such as unemployment, poverty, homelessness, and discrimination.⁸ Ultimately, hopelessness, the feeling that there is no prospect of improvement in one's situation, is a strong indicator of suicide.⁹

Lunar phase

Although several studies have found limited support for lunar effects in abnormal behaviour, most have failed to show any relationship between such behaviour and the phase of the moon.¹⁰ In particular, a review of twenty studies examining correlations between moon phase and suicides showed that most of these studies found no correlation, and the ones that did report positive results were inconsistent with each other.¹¹

Nevertheless, human and animal physiology is subject to lunar rhythms.¹² The lunar cycle has been found to influence human fertility, menstruation and birth rate.¹² Moreover, strong lunar cycle effects were found in stock returns. Returns in the 15 days around new moon dates were about double the returns in the 15 days around full moon dates. Evidence suggests that pessimism follows a sinusoidal pattern along the lunar cycle, with people become increasingly pessimistic in the 15 days around full moons, and increasingly optimistic around new moons.¹³

There does not seem to be published research on the lunar eclipse (which occurs the night of a full moon) or solar eclipse (which happens during a new moon) in relation to human behaviour.

Lunar apogee and perigee

Although there seems to be no published study of the apogee-perigee cycle in relation to humans or animals, the apogee-perigee cycle has been observed in the timing of volcanic eruptions and an eight-fold increase in earthquakes was found during the First and Last Quarter at perigee.¹⁴ It has also been noted that natural disasters such as the South East Asia earthquake and tidal wave disaster of 26 December 2004 (the day of Full Moon and the day before apogee) are more likely to occur at Full Moon, especially if the moon is at apogee.¹⁵ Apparently the earth is subject to exceptional strains when the moon is at apogee, particularly when this occurs at Full Moon.¹⁵

Seasons

Seasonal affective disorder (SAD) is a mood disorder in which people who have normal mental health during most of the year experience depressive symptoms in the winter or summer, spring or autumn, year after year.¹⁶ This condition in summer is often referred to as reverse seasonal affective disorder, and can also include heightened anxiety.¹⁷ About 20% of Irish people are affected by SAD¹⁸ and an estimated 10% of the Netherlands population suffer from SAD.¹⁹

Seasonal mood variations seem to be related to light.²⁰ It has been theorized that the cause may be related to melatonin which is produced in dim light and darkness by the pineal gland, since there are direct connections, via the retinohypothalamic tract and the suprachiasmatic nucleus, between the retina and the pineal gland.²¹

Suicides fall during the winter months and peak during spring and early summer.²² As there is a correlation between the winter season and rates of depression, it has been suggested that individuals decide to commit suicide while profoundly depressed in winter when they lack the ability to organize their death. Later, when the weather improves and the person feels more in control, they are able to arrange their suicide.²³

Purpose of the present study

The purpose of this study was to investigate the nature of any relationship between lunar phase and abnormal behaviour by broadening the scope of the typical study in this field to include variables of the apogee-perigee cycle and season.

Method 

The dates of 43,645 suicides in England and Wales from 2001 to 2010 were classified and compared according to lunar and seasonal characteristics. The suicide dates were the known dates of suicides as defined and recorded by the Office for National Statistics. The dates were studied in relation to lunar phase, which was divided into halves; lunar apogee and perigee; and twelve annual seasonal periods determined by equinox and solstice dates and the division of each season into three equal periods. A chi-square (X²) statistic was used to investigate whether the distribution of suicide dates differed according to these variables. P-values were calculated with two tails. 

Summary of findings 

The below-mentioned results were statistically significant, with p-values of 0.0000 from the seasonal variation variable onwards. The lunar and seasonal factors are presented in order of increasing association with suicide risk.

1. Lunar and solar eclipse -- weak effect (0.8% and 0.9% increases respectively).

2. Lunar phase differences -- small. Fewest suicides occurred during New Moon phase and the largest difference (between New Moon and First Quarter) was 0.9%.

3. Seasonal variation -- suicide numbers rose and fell in trends that peaked in mid spring (about 20 April to 21 May) and troughed in late autumn (about 21 November to 21 December). The difference between these highest and lowest months was 2.1%

4. Lunar phase and apogee / perigee

4.1 Lunar phase and apogee -- Suicides increased substantially when the moon was close to apogee, with biggest increases around Full Moon (6.4%) and New Moon (5.7%).

4.2 Lunar phase and perigee -- Suicides decreased substantially when the moon was close to perigee, with biggest decreases around New Moon (-5.8%) and Full Moon (-5.5%).

5. The lunar phase and apogee / perigee effect varied by season.

The findings referred to in 4.1 and 4.2 obscure the variation in strength and direction of the apogee / perigee effect according to season, e.g. around Full Moon and near apogee, suicides largely decreased (-12.1%) during early Spring but largely increased (11.1%) during mid Summer. Conversely, around Full Moon and near perigee, suicides largely increased (12.7%) during early Spring but decreased (-7.8%) during mid Summer.

Conclusion 

Consistent with previous research, this study found that lunar phase alone is of limited value in explaining the distribution of suicide dates. However, in conjunction with the apogee-perigee cycle and seasonal periods, lunar factors can explain variations in the distribution of suicide dates to a substantial degree. Concepts of stress, particularly those of distress and eustress, under-stimulation and over-stimulation, can provide a coherent way of thinking about the present findings.

References

1. Koolhaas, J., et al. (2011). Stress revisited: A critical evaluation of the stress concept. Neuroscience and Biobehavioral Reviews, 35, 1291–1301.

2. Lazarus, R. S., & Folkman, S. (1984). Stress, appraisal, and coping. New York: Springer.

3. Lazarus, R. S. (1999). Stress and emotion: a new synthesis. New York: Springer.

4. Lundberg, U. (1984). Human psychobiology in Scandinavia: II. Psychoneuroendocrinology—human stress and coping processes. Scandinavian J of Psychology, 25 (3), 214–26.

5. Hawton K., & van Heeringen, K. (2009). Suicide, Lancet, 373 (April), 1372–81.

6. World Health Organization (2006). Suicide prevention. WHO Sites: Mental Health, (16 Feb).

Retrieved 2011-12-29.

7. Teasdale T. W., & Engberg, A. W. (2001). Suicide after traumatic brain injury: a population study. J Neurol Neurosurg Psychiatry, 71(4), 436-40.

8. Qin P., Agerbo, E., & Mortensen, P. B. (2003). Suicide risk in relation to socioeconomic, demographic, psychiatric, and familial factors: a national register-based study of all suicides in Denmark, 1981–1997. Am J Psychiatry, 160 (4), 765–72.

9. Beck, A. T., Steer, R. A., Kovacs, M., et al. (1985). Hopelessness and eventual suicide: a 10-year prospective study of patients hospitalized with suicidal ideation. Am J Psychiatry, 142 (5), 559-63.

10. Chulder, E. Moonstruck! Does the full moon influence behavior?". Neuroscience for Kids. U of Washington. http://faculty.washington.edu/chudler Retrieved 2011-12-29.

11. Kelly, I., Rotton, J., & Culver, R. (1996). The moon was full and nothing happened: a review of studies on the moon and human behavior. Revised and updated in The Outer Edge: Classic Investigations of the Paranormal, edited by J. Nickell, B. Karr, & T. Genoni, CSICOP.

12. Zimecki, M. (2006). The lunar cycle: effects on human and animal behavior and physiology.

Postepy Hig Med Dosw, 60, 1-7.

13. Dichev, I. D., & Janes, T. D. (2003). Lunar cycle effects in stock returns. J of Private Equity, Fall, 8-29.

14. Pasichnyk, R. M. The living cosmos. www.livingcosmos.com Retrieved 2011-12-29.

15. National Association for Scientific and Cultural Appreciation. www.nasca.org.uk

Retrieved 2011-12-29.

16. American Psychiatric Association (1994). Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Washington, DC.

17. Mayo Clinic. Seasonal Affective Disorder. www.mayoclinic.com Retrieved 2011-12-29.

18. BreakingNews.ie - One in five suffers from SAD www.breakingnews.ie Retrieved 2011-12-29.

19. Elsevier – Dark days: winter depression (Dutch) www.elsevier.nl Retrieved 2011-12-29.

20. Lam, R. W., Levitt, A. J., Levitan, R. D., Enns, M. W., Morehouse, R., Michalak, E.E., & Tam, E. M. (2006). The Can-SAD study: a randomized controlled trial of the effectiveness of light therapy and fluoxetine in patients with winter seasonal affective disorder. Am J of Psychiatry, 163 (5), 805–12.

21. Brainard, G. C., Hanifin, J.P., Greeson, J. M., Byrne, B., Glickman, G., Gerner, E., & Rollag, M. D. (2001). Action spectrum for melatonin regulation in humans: evidence for a novel circadian photoreceptor. J of neuroscience : the official j of the Society for Neuroscience, 21 (16), 6405–12.

22. NPR: Study: Suicides drop during holidays. www.npr.org Retrieved 2011-12-29.

23. Ontario Consultants on Religious Tolerance. www.religioustolerance.org

Retrieved 2011-12-29.

Resources

From Earth and Moon Viewer and Solar System Explorer:

View of Present Moon

Perigees and Apogees, New and Full Moons