The association between formal thought disorder and finger print asymmetry in children with a psychiatric disorder: an exploratory study.

Dermatoglyphics are the ridge constellations found on the hand palms and foot soles that are permanently formed by the 24th week of pregnancy. Associations have been found between adult schizophrenia and irregularities 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 significantly 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 possible marker of prenatal instability, was associated with the occurrence of FTD in girls.