Sleep is a critical activity in our mental and physical health. Sufficient sleep is necessary for learning, productivity, and emotional regulation. It boosts our energy, improves our performance, and helps us prevent injury, making it an athletic necessity on par with hydration and nutrient intake. Sleep deprivation, meanwhile, has been linked to an increased risk of stroke, obesity, cardiovascular disease, and onset dementia. And without it, your glymphatic system doesn’t have the time to properly scrub your brain of the toxic protein beta-amyloid—meaning your head fills up, literally, with unfiltered daytime gunk.
For children, sleep is even more cruci
al. A meta-analysis of ten studies on infant sleep and cognition found a “positive association between sleep, memory, language, executive function, and overall cognitive development.” In other words, all the ingredients for a healthy mind and social aptitude. It’s so necessary for cognitive development that by age two a child will spend more time asleep than awake. In total, 40 percent of our childhoods are spent mapping our personal dreamlands.
But a recent study in JAMA Psychiatry suggests the obverse is also true. Poor sleep routines, chronically disrupted sleep, and other parasomnias may have an adverse effect on children’s mental health later in life.
Previous studies had already suggested a link between persistent nightmares in childhood and psychosis and borderline personality disorder (BPD) by adolescence, but researchers at the University of Birmingham’s School of Psychology wanted to see if a similar connection existed between these mental disorders and other childhood behavioral sleep problems.
To do this, they scoured data from the Avon Longitudinal Study of Parents and Children, a longitudinal cohort study that followed approximately 14,000 children born in Avon, England, in the early 1990s. The study followed the children for more than 13 years. During that time, mothers filled out questionnaires asking about the children’s lives. Factors looked at included housing, parenting, nutrition, physical health, mental wellbeing, environmental exposures, and so on.
The cohort study inquired about sleep routines, sleep duration, and awakening frequency when the children were 6, 18, and 30 months old, and then again at 3.5, 4.8, and 5.8 years. It also assessed mental health in adolescence using semi-structured interviews, such as the Psychosis-Like Symptom Interview.
“We know that adolescence is a key developmental period to study the onset of many mental disorders, including psychosis or BPD. This is because of particular brain and hormonal changes which occur at this stage,” Steven Marwaha, professor of psychiatry at Birmingham and senior author on the study, said in a release. “Sleep may be one of the most important underlying factors—and it’s one that we can influence with effective, early interventions, so it’s important that we understand these links.”
After compiling the data, the researchers discovered an association between children with irregular sleeping patterns and teenagers with psychotic experiences—that is, episodes when the person perceives reality differently than those around them. Even when depression at 10 years old was considered as a mediating factor, their findings still suggested “a specific pathway between these childhood sleep problems and adolescent psychotic experiences.”
Toddlers with shorter nighttime sleep duration and late bedtimes were likewise associated with a borderline personality disorder—a disorder marked by a pattern of varying moods, self-images, and behaviors—in their teenage years. Depression at age 10 did not mediate this particular association, suggesting a separate and more specific pathway.
While the sample size was large and mental health was assessed with a validated interview, there nevertheless remain limitations to this data. For starters, sleep habits were based on mothers’ reports. Because they came from memory, versus a more direct observation method such as actigraphy, these data may be prone to imperfect recollection and reporting error. There are also many confounders that could be secretly nudging the results, such as family conditions, prenatal medicines, and a host of environmental factors. Finally, the relationship between sleep problems and mental disorders is both complex and two-way.
As such, the study shows an association between poor childhood sleep later mental disorders but does not prove a causal link. Parents need not worry that a string of nightmares or the eternal struggle settle into bed will be the first ingredients in a witches’ brew of debilitating mental disorders. The goal of the study, the researchers point out, is not to create undue worry but improve our ability to recognize the signs of at-risk children and deliver necessary interventions earlier.
“The results of this study could have important implications for helping practitioners identify children who might be at higher risk for psychotic experiences or BPD symptoms in adolescence, and potentially lead to the design of more effectively targeted sleep or psychological interventions to prevent the onset or attenuate these mental disorders,” Isabel Morales-Muñoz, the study’s lead researcher, told Healio Psychiatry.
If a parent reading this is worried that their child’s sleep patterns are deleterious, the take away should not be despair over an unyielding fate. It should be to seek professional help as soon as possible to begin improving sleep duration and quality. Even if you aren’t worried, it’s worth remembering that childhood experiences lay the foundation for a lifetime of salubrious sleeping habits. It’s so much more than beauty rest.