Without evidence of benefit, an intervention should not be presumed to be beneficial or safe.

- Rogue Medic

Friday the 13th and full-moon – the ‘worst case scenario’ or only superstition?


 
Today we get hit with a double whammy – Friday the 13th and a full moon. This will not happen again until August of 2049.

Is there anything about Friday the 13th, or the full moon, or the combination that would make today worse than usual?

Let’s look at the evidence.

The last combination of Friday the 13th and a full moon was in October 2000. Somebody decided to compare patient volumes by category against other full moon days and also against the average volume.
 

One of the oldest superstitions is about Friday, the number 13, and a full moon. There exists a very popular belief in the relationship between the number 13 and Friday as well as the moon’s phase and the incidence of bad luck. Among the emergency department “folklore” belongs the theory that shifts on such dates are always busy ones.[1]

 

We compared the number of overall admissions divided into medical, nontrauma-related surgical emergencies, mild and moderate trauma, multiple injured patients, and attempted suicides, on the full moon days and nights from February 2000 to Friday, October 13, 2000 with the average admission rate per day during this period.[1]

 

Here are the numbers.
 


 

Nothing unusual there.
 


 

Still nothing unusual.
 


 

A higher number of non-trauma surgical emergencies on Friday the 13th with the full moon, but this is the only one category. Does anything else suggest a connection?

Trauma will clearly show the power of this double hex day to do harm.
 


 

That seems to be beneficial. That can’t be right.
 


 

That, too.

This is downright depressing.
 


 

Worse than depressing – even the suicides were not increased.
 

The data analysis showed no significant difference between Friday the 13th of October compared with our average full moon admission rate (Table 2).

Even fewer trauma patients were seen on this day compared with other full moon days and nights. Furthermore, the present study could not show any difference in the admission rate on days with a full moon, compared with a normal day, disappointing once again a lot of believers in “hospital folklore.”[1]

 

It isn’t proof, but there is plenty of other evidence against full moon superstition and others.

Maybe someone will collect data on the volumes from today and compare them with normal days and with normal full moon days.

I have written about full moon superstitions before.
 

Blue Moon 2012 – Except parts of Oceanea – Fri, 31 Aug 2012

2009’s Top Threat To Science In Medicine – Fri, 01 Jan 2010

T G I Friday the 13th – Fri, 13 Nov 2009

Happy Equinox! – Thu, 20 Mar 2008

Footnotes:

[1] Friday the 13th and full-moon: the “worst case scenario” or only superstition?
Exadaktylos AK, Sclabas G, Siegenthaler A, Eggli S, Kohler HP, Luterbacher J.
Am J Emerg Med. 2001 Jul;19(4):319-20. No abstract available.
PMID: 11447523 [PubMed – indexed for MEDLINE]

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