ORIGINAL CONTRIBUTION The association between formal thought disorder and finger print asymmetry in children with a psychiatric disorder: an exploratory study Esther I. de Bruin • Pieter F. A. de Nijs • Frank C. Verhulst • Anja C. Huizink Received: 27 October 2011 / Accepted: 5 July 2012 Ó Springer-Verlag 2012 Abstract Dermatoglyphics are the ridge constellations found on the hand palms and foot soles that are perma- nently formed by the 24th week of pregnancy. Associations have been found between adult schizophrenia and irregu- larities and asymmetries in dermatoglyphics. Children have not been studied before. The aim of this study was to assess the association between formal thought disorder (FTD), as a possible forerunner of schizophrenia, in children and asymmetry or discordance (DISC) of the finger prints. 222 children, aged 6–14, from an outpatient department of child psychiatry participated. Finger prints were rated with the three-pattern system (whorls, loops or arches). FTD criteria were illogical thinking (ILL), loose associations (LA), incoherence (INC), and poverty of content of speech (POC), as rated by the clinician. When boys with and without DISC were compared, no differences in FTD were found. In contrast, however, girls with DISC showed sig- nificantly more FTD than girls without DISC, t (72) = -2.39, p = 0.02. Further, for boys, only total FTD was positively correlated with DISC of the middle finger, r = 0.20, p = 0.02. For girls, total FTD was positively correlated with DISC of the index finger: r = 0.30, p = 0.02; DISC of the middle finger: r = 0.27, p = 0.03; and with total DISC dichotomous: r = 0.27, p = 0.02. In addition, total DISC correlated positively with ILL: r = 0.31, p = 0.01; LA: r = 0.23, p = 0.05; INC: r = 0.30, p = 0.01; and total FTD: r = 0.31, p = 0.01. Overall, the existence of finger print discordance, as a pos- sible marker of prenatal instability, was associated with the occurrence of FTD in girls. Keywords Finger print patterns Á Dermatoglyphics Á Child psychiatry Introduction Dermatoglyphics are the ridge constellations found on the hand palms and foot soles. They have been studied for nearly 120 years [1]. Dermatoglyphics are formed from the 10th week of pregnancy [2]. From the 24th week derma- toglyphics remain unchanged and, therefore, can be con- sidered as trait markers, or as fossils of a specific period of prenatal development [3, 4]. Syndromes such as Down’s syndrome [5] or fragile-X syndrome [6] are associated with irregularities in finger and hand palm prints and ridge counts. The morphology of the ridges is determined by our genes but can also be affected by environmental stress such as an infection such as rubella or the abuse of alcohol or drugs [7]. The most frequently studied dermatoglyphic variables are the ridge counts on the fingertips, the a-b ridge counts on the palm, the atd-angle on the palm, and the ridge patterns on the fingertips. Our study will focus on the fingertip patterns. Dermatoglyphic patterns are sometimes used as proxy markers of prenatal instability in schizophrenic or psy- chotic development. The underlying idea is that certain brain developments take place at the same prenatal time period, and from the same ectoderm, as dermatoglyphic development does, such as the formation of the ridges on E. I. de Bruin (&) Á P. F. A. de Nijs Á F. C. Verhulst Outpatient Department of Child and Adolescent Psychiatry, Erasmus Medical Center Rotterdam/Sophia Children’s Hospital, Dr. Molewaterplein 60, 3015 GJ Rotterdam, The Netherlands e-mail: e.i.debruin@uva.nl A. C. Huizink Department of Developmental Psychology, Faculty of Psychology and Education, VU University Amsterdam, Amsterdam, The Netherlands 123 Eur Child Adolesc Psychiatry DOI 10.1007/s00787-012-0309-2