Urinary catecholamines as a measure of emotional stress in children with a digit-sucking habit: a preliminary study.

This cross-sectional study investigated the relationship between digit-sucking habit and emotional stress measured by the urinary catecholamines in 314 children, boys and girls, ages six to eight years. The digit-sucking habit was recorded by an interview. A twenty-four hour urine sample was collected for each subject and a representative sample was analyzed by the HPLC technique to assay the catecholamine content. Socioeconomic factors were recorded by a questionnaire distributed to the parents. The logistic multiple-regression analysis was used to test the impact of catecholamines and other related factors on the presence of a digit-sucking habit. The results showed that emotional stress measured by the urinary catecholamines did not have a significant effect on the presence of a digit-sucking habit. Of the socioeconomic factors, father's education had a significant negative effect on the presence of the habit. The evidence provided by this investigation cannot support the view of psychoanalytic theory that continuation of the habit beyond the early childhood is due to emotional stress.