Infantile Colic is a diagnosis of varying descriptions from the literature, the criteria proposed by Wessel in 1954 is often the benchmark used when considering a diagnosis of colic.
Colic was proposed as being excessive crying, or paroxysmal fussing,
of at least 3 hours a day,
on at least three days a week,
for at least three weeks.

It occurs in an otherwise healthy infant, with inconsolable crying and high pitch crying. The incidence of colic is estimated as 8-40% of infants, with symptoms occurring 2-3 weeks postnatally.

Barr et al (1996) compared crying patterns in preterm infants to those carried to full term. It was concluded that the age of crying was not related to gestational age at birth. It was found that crying peaked at the third month of age, and that variables such as weight for gestational age, or a variety of other perinatal and neurological indices didn’t influence the likelihood of developing symptoms of colic.

Interestingly other causes for the paroxysmal fussing may include somatic responses to the presence of tension in the environment, i.e referring to the family dynamics and environment. The term “evening colic” referring to the circadian rhythm in the nature of crying in the early evening onwards.