LAUSR

1496 www.thelancet.com Vol 389 April 15, 2017 “Sir—The evacuation of small children between the ages of 2 and 5 introduces major psychological problems.” This sentence by John Bowlby and colleagues published in The BMJ in 1939 warns against the detrimental effects of separation of young children from their mothers. During World War 2, children in the UK were evacuated to unfamiliar families for reasons of safety. The professional attention to the effects of family disruption preceded the attention to serious physical and emotional deprivation of children raised in residential institutions such as orphanages as a result of war. Since Bowlby’s report for WHO about the negative effects of institutional deprivation, it is now well established that early deprivation faced by many institutionalised children has serious consequences for children’s neurobiological, social, behavioural, and cognitive development. However, less is known about the effects of timing and duration of adverse exposures and its pervasiveness on later development. This type of knowledge is important because it can inform child mental health professionals about how to treat or prevent the effects of early deprivation. The young adult follow-up of the longitudinal English and Romanian Adoptees study by Edmund Sonuga-Barke and colleagues in The Lancet fills an important knowledge gap on the long-term mental health consequences of early severe childhood deprivation. The authors followed up two groups of children who were assessed in childhood at ages 6, 11, and 15 years and in young adulthood at ages 22–25 years. The first group consisted of children raised in Romanian institutions from soon after birth to up to 43 months who were removed out of deplorable living conditions—characterised by severe physical, emotional, and social deprivation—and placed into stable and caring families in the UK. This group was separated into those who had spent less than 6 months in an institution (n=67 at age 6 years; n=50 at young adulthood) and those who spent more than 6 months in an institution (n=98 at age 6 years; n=72 at young adulthood). The second group consisted of UK adoptees who did not experience deprivation as a comparison group (n=52 at age 6 years; n=39 at young adulthood). The authors carefully assessed both groups using developmentally appropriate standardised procedures (questionnaires and interviews for adoptees and their parents, and direct measures of IQ) across the four assessment waves. Using these procedures, Sonuga-Barke and colleagues determined symptoms of autism spectrum disorder, inattention and overactivity, disinhibited social engagement, conduct or emotional problems, and cognitive impairment (IQ score <80). This study is unique because it directly compares the developmental course of a wide range of behavioural, social, and cognitive measures in children who experienced extremely poor physical and social circumstances before adoption with that of adopted children who did not experience deprivation, it followed both groups across extended developmental periods from childhood into adulthood with multiple assessments, and it contrasted the development of severely deprived children adopted before 6 months of age with those who spent more than 6 months in an institution. The most salient finding was that children severely deprived up to 6 months and non-deprived UK adoptees had similarly low levels of problems, whereas severe deprivation lasting 6 months or more had persistent detrimental effects on individuals’ behavioural and social development in terms of symptoms of autism spectrum disorder, disinhibited social engagement, and inattention and overactivity through to young adulthood (pooled p<0·0001 for all), despite the fact that they were raised in supportive and caring adoptive families. Compared with the UK controls, the high deprivation group also had a higher proportion of people with low educational achievement (p=0·0195), unemployment (p=0·0124), and mental health service use (<11 years p=0·0120, 11–14 years p=0·0032, and 15–23 years p=0·0003). The longitudinal comparison across the four assessment waves revealed two interesting findings that would have stayed unnoticed if only young adult data had been used. The higher rates of cognitive impairment in the high deprivation group at ages 6 years (p=0·0001) and 11 years (p=0·0016) compared with the UK controls remitted to normal rates at young adulthood (p=0·76). By contrast, emotional problems in the high deprivation group (depression and anxiety) showed a late onset pattern with a significant increase in levels from ages 11 and 15 years to young adulthood (p=0·0005). This study raises three questions. First, are the findings in line with the concept of sensitive periods in which particular experiences are essential for normal development? During brain development, there seem Early life deprivation: is the damage already done?