By DR FIONA MENSAH and GEORGE PATTON
Puberty has long been recognised as a transition point in which many emotional and behavioural problems emerge. These include depression and anxiety, substance use and abuse, self-harm and eating disorders.
We previously thought that children who entered puberty earlier than their peers were at greater risk of these problems because they were less equipped to cope with the transition. This may be part of the story.
But we’re increasingly realising that social and emotional disadvantages and stresses in childhood may trigger early puberty. This possibility was explored in a study published today in the Journal of Adolescent Health, which found children who go through puberty early showed signs of poorer mental health in early childhood.
We studied a cohort of 3,491 children and families from the Longitudinal Study of Australian Children. Parents reported behavioural difficulties and emotional, social and school functioning in four surveys between ages four and 11. Around 16% of girls and 6% of boys had begun puberty by age eight to nine.
We found that boys with an earlier onset of puberty had greater behavioural difficulties and poorer emotional and social adjustment. These difficulties began as early as four to five years of age and continued to early adolescence.
Girls who reached puberty early also had more difficulties in emotional and social adjustment from early childhood. But these girls did not have the increased behavioural problems found in boys.
When does puberty start?
Puberty is the stage of development in which a child’s body matures to enable reproduction. This includes the development of breast tissue and the first period in girls, and maturation of the testes in boys. The hormonal changes that lead to sexual maturation during puberty are accompanied by major physical growth and maturation of the brain.
Puberty typically begins in late childhood. On average, girls begin puberty at ages ten to 11; boys start at 11 to 12. But the timing of puberty varies by four to five years among healthy children. This reflects the effects of nutrition, psychological status and socioeconomic conditions. Studies also suggest that genes play a role.
The age of first menstruation has dropped significantly since the 1840s, when the average age in Western European girls was around 16. Since the 1960s this trend has ceased in most developed countries and the average age is now 12 to 13.
Within countries, differences in pubertal age may be found according to socioeconomic status and racial origin. Data from the United States, for example, found that black American girls begin puberty earlier than white or Mexican-American girls.
Emotional and behavioural problems
We know that adversity in life – such as stressful family circumstances or a lack of care and warmth – can affect the rate and course of a child’s development. Early psychosocial stress can be a cue for environmental risk and trigger earlier reproductive development. From this perspective, emotional and behavioural problems would be expected to occur even before early puberty is evident.