"Although these boys at age 8 included only 4 percent of the sample, they were responsible for more than one fourth of all crimes between age 16 and 20 in this sample," Dr Andre Sourander of Turku University Hospital, the study's lead author, told Reuters Health.
As reported in the Journal of the American Academy of Child and Adolescent Psychiatry, Sourander and his colleagues followed 2 556 boys born in 1981 from age 8 up to age 23 to determine how psychological problems in childhood affected later life.
Psychological profiles They divided boys with psychological problems into different groups: those with both conduct problems and so-called internalizing disorders such as depression or anxiety; those with conduct problems only; boys with attention problems alone; boys with internalizing disorders alone; and boys who themselves reported high levels of distress, but who weren't thought by parents or other observers to have psychological problems. The researchers referred to this last group as the "invisible children."
Among the conduct and emotional problems group, who made up 4.3 percent of all boys in the study, two-thirds were in need of mental health help at age eight, according to their parents or teachers. However, almost none of them got such help, either in childhood or later on.
Nearly half committed crimes
By age 18 to 23, 32 percent of the study participants with both conduct and emotional problems had been diagnosed with a psychiatric disorder, while 48 percent had committed a crime by age 20.
Boys with conduct problems alone or attention problems were at lower risk of later criminal activity and psychiatric problems. Those with emotional problems only and the "invisible children" fared the best, although they were still at greater risk than their peers with no mental health problems in childhood.
"Our findings suggest that screening of child mental health problems is most important," said Sourander, who pointed out that parent training groups and cognitive behavioural therapy have both been shown to be helpful in treating conduct problems in children.
Early detection essential
"The strategy of early detection, screening, assessment and follow-up should be similar to any other severe chronic childhood disorders, such as diabetes or asthma," he added.
Sourander concluded: "We need further research on psychosocial, biological and genetic risk factors (for) these boys who are 'affectively and behaviourally dysregulated' and are in greatest risk for later adversities." - (Anne Harding/Reuters Health)
SOURCE: Journal of the American Academy of Child and Adolescent Psychiatry, September 2007.