Monday, 10 September 2012

Come Sta La Luna: fingernails and depression


I saw it written and I saw it say
Pink moon is on it's way
And none of you stand so tall
Pink moon gonna get you all
It's a pink moon
Hey, it's a pink moon 
Nick Drake (Pink Moon)

Psychiatry Research has just published a somewhat leftfield paper about fingernails and depression by a group of Chinese scientists. The association between absent lunula and depression in depressive outpatients: A case-control study by Zhou et al (2012).  It concerns  the lunula (Latin Little Moon), which is the white, half-moon shape often visible on all fingers except the little finger.

File:Fingernail label (enwiki).jpg

Absent lunula are apparently associated with various systemic disorders including hypopituitarism, hypothyroidism, iron deficiency anaemia, arteriosclerosis, malnutrition, chronic renal failure, and even cancer (e.g. Cohen, 1996).

Zhou et al state that in "Traditional Chinese Medicine absent Lanula are associated with lower physiological response and bad microcircualtion" and then use this as leverage for hypothesising that absent lunula may be linked to depression.

 Present Lunula                                                                                 Absent Lunula

The authors examined fingernails in a large sample of 332 depressive outpatients (aged between 19 and 67) without cutaneous, congenital or other systemic diseases; and without application of drug and henna that might contribute to any change of lunula. They compared the patients with a similarly large sample of 367 healthy controls, who were drawn from ‘spouses of the patients’ or local residents. The two groups were well matched for age and sex.
Come Sta La Luna (by Can) - if feeling unwell, the cure is in the Can

The Zung Self rating Depression Scale (ZSDS: Zung, 1965) was used to measure the level of depression with scores of <50 =normal; 50–59=mild depression; 60–69=moderate depression; and 70=severe depression (Lin et al., 2009).

Then they simply observed for absence of luluna on right hand (as right and left tend to be identical in this respect). People were classified as having 1,2, 3 or no luluna (as noted the little finger is excluded having no lunula anyway)

Pink Moon (by Nick Drake) followed by the Black Dog

A large difference emerged with only 17.2% of depressed having all 4 lunula present compared to 68.1% of controls. At the other end, 23.7% of the depressed group and only 9.8 of controls had 4 missing (see Table 2)

Table 3 compares absent lunula in relation to depression severity within the depressed group. The table show no differences in sex and age composition between mild/moderate vs severely depressed but that 69% of severe depressed have >3 absent lunula while in the mild/moderate depressed this figure is 41.7%.

Conclusion - mechanism?
The authors state that
"Though the mechanism of absent lunula is still not clear and disputed, previous researches [sic] agreed that absent lunula reflects a variety of complex factors including metabolic changes in addition to anaemia (Dyachenko et al., 2007;Salem et al., 2008;Saray et al., 2004). Metabolic changes are also included in the mechanism of depression, such as the metabolic disorders of angiotensin-converting enzyme, serotonin, monoamine, cortisol, brain-derived neurotrophic factor, melatonin and so on (Akpinar et al., 2008; Annerbrink et al., 2010; Belmaker and Agam, 2008; Montag et al., 2010; Okuno et al., 2011; Wang et al., 2009). Therefore, it may be possible that absent lunula and depression have a common metabolic process leading to the co-occurrence of them."
While the explanation is somewhat speculative and opaque, it is an intriguing finding showing that a small visible finger detail (lunula) may provide information about inner mental state. Looking at my own fingers, my two hands are quite different - lateralised depression! Perhaps a link between mental health and the 'Moon' has some basis after all, but in a positive manner ...check for your good Moon rising...

Gordon Brown's hands
Whose nails are they ...was he depressed? Not mine! (but belong to someone well-known at least to UK public)



  1. A very, very interesting post.

    I don't know if it is rooted in fact or not, but there is some speculation that disappearing lunula might also be related to issues with the availability of vitamin B12.

    1. Thanks Paul - yes apparently it has been linked to B12 deficiency (which of course may raise a host of other related problems)

  2. So we can just count the lunula and not ask participants to fill in those pesky questionnaires with intrusive questions about crying, sleepless nights, weight change and suicidal thoughts that Ethics Committees get so prickly about. Cool.

    1. And 'Nail Bars' could sell false lunula as a cure

  3. I wonder whether they would reappear with successful treatment and/or resolution of the cause, and how long that might take.