Evidence for involvement of central noradrenergic activity in crying proneness

Crying as a response to emotionally-charged situations varies greatly among individuals, genders, and cultures. Information on the neural systems involved in crying behavior comes mainly from studies of pathological laughing and crying in patients after brain injury. The authors assessed crying proneness (CPR) as expressed by the score on the "crying easily" item of the SCL-90 questionnaire in 65 men and 105 women subjects in whom lumbar puncture was performed for diagnostic reasons. None of the subjects showed pathological laughing or crying. The authors estimated the levels of the main metabolites of noradrenaline (MHPG), serotonin (5-HIAA), and dopamine (HVA) in CSF, and searched for associations to CPR score. Subjects with high CPR showed significantly lower MHPG levels than subjects with low CPR, and no differences in 5-HIAA or HVA levels. Higher frequencies of women were found in the subgroups with high CPR. The "crying easily" score was positively associated with the Interpersonal Sensitivity subscale of the SCL-90 questionnaire in female but not in male subjects, indicating the cultural dimension of crying behavior, while it was not associated with the Depression subscale score. It is suggested that central noradrenergic mechanisms control the threshold for tear production in normal crying behavior.