Colic

Ronald Barr, Ian St. James-Roberts, and Maureen Keefe (2001) brought together our knowledge of infant crying and its impact on Western parents and clinical services. The principal findings can be summarized as follows:

1. In general, Western infants cry about twice as much in the first three months as they do at later ages, with the amount of crying peaking at around five weeks of age (the infant crying peak). Around two hours of fussing and crying in twenty-four hours has been reported in U.S., Canadian, and English samples. Rather less has been reported in other European countries, but the reason for this is not yet clear. Infant crying at this age also clusters in the evening (the evening crying peak);
2. As well as its greater amount, infant crying in the first three months has distinct qualitative features, which help to explain its impact on parents. These include the existence of bouts which occur unexpectedly and are prolonged, relatively intense to listen to, and difficult to soothe effectively;
3. Parental complaints to clinicians about infant crying problems also peak during the first three months, while infants identified in this way share the same features as other infants, but often to a more extreme degree. This has led to the view that many infants identified as problem criers—and hence labelled as colic cases—are at the extreme end of the normal distribution of crying at this age, rather than having a clinical condition;
4. Crying in the early months is a graded signal, which signals the degree of an infant's distress, but not precisely what is causing the crying (Gustafson, Wood, and Green 2000). It was previously believed that babies had different cry "types" (e.g., hunger, anger, pain) that allowed a sensitive parent to detect the causes of crying and to intervene to stop it. The unfortunate implication was that a baby who cried a lot had incompetent parents. Instead, it has become clear that "reading" the cause of crying from its sound is at best difficult and, in everyday circumstances, often impossible during the first three months. At this age, babies may cry intensely but the cry itself does not tell you what the problem is;
5. Most babies grow out of their crying as they get older. Providing their parents can cope, follow-up studies have found that the infants are normal in their cognitive, social and emotional development, and sleep. However, a small minority do have long-term problems (Papousek and von Hofacker 1998). It is not yet clear whether these infants are different in what causes their crying, or in how their parents respond to and care for their babies over the long term.
6. Women who are prone to depression can have their depression triggered by an objectively irritable newborn (Murray et al. 1996). This emphasizes the need to consider infant crying and colic in terms of parental and family vulnerability, rather than solely as an infant phenomenon.