VIENNA – They say that in hula dancing, it’s the expressive hands, not the quaking hips, that tell the story.
And in Dutch women, a relatively short index finger on the left hand bespeaks an increased risk for depression and stress.
That’s right: The ratio of the length of the index finger to the ring finger, or 2D:4D digit ratio, of the left hand shows potential as a quick and dirty biomarker that could be used to screen patients for increased risk for depression. But only in women, Deborah De Kruijff reported at the annual congress of the European College of Neuropsychopharmacology.
She and her coinvestigators measured the lengths of the index and ring fingers on both hands of 124 male and 146 female Dutch college students using Vernier calipers accurate to within 0.01 mm. Participants completed the 21-item version of the Depression, Anxiety, and Stress Scale (DASS-21) and correlated the 2D:4D digit ratios with the DASS-21 total scores as well as the scores on the depression, anxiety, and stress subscales.
The 2D:4D digit ratio didn’t correlate with DASS-21 scores in men. But in women, the lower the 2D:4D ratio on the left hand, the higher their overall DASS-21 score as well as their scores on the depression and stress subscales. Each of these associations was highly statistically significant at the P = .002 to .005 level, according to Ms. De Kruijff, a PhD candidate in neuroscience at Utrecht (the Netherlands) University.
Finding correlates between the 2D:4D digit ratio and predispositions to various diseases, personality traits, and other human characteristics was a popular scientific pastime in the 1800s. After a long dry spell, it rebounded as a research area several decades ago. The 2D:4D ratio is a sexually dimorphic trait. It is thought to depend upon prenatal exposure to sex hormones. A low 2D:4D ratio is associated with in utero exposure to relatively higher levels of fetal testosterone than fetal estrogen. Thus, a greater proportion of men than women have index fingers that are shorter than the ring finger.
Other investigators have linked a low 2D:4D ratio to increased risks of prostate cancer, attention-deficit/hyperactivity disorder, and autism spectrum disorder in men, and to greater assertiveness and increased risk of anorexia nervosa in women.
Ms. De Kruijff said more research is needed to understand why only the finger length on the left hand of the women was predictive of increased risk of depression and stress.
She reported having no financial conflicts of interest regarding this university-funded study.