Teens who have celiac disease appear to suffer more frequently from mental disorders — specifically, depression and disruptive behavior disorders such as attention deficit-hyperactivity disorder and oppositional defiant disorder — than their non-celiac peers.
It's not clear why this occurs, but researchers speculate that malnutrition caused by celiac disease may play a role.
Regardless of the reason, there's some evidence that depression, ADHD and other behavior problems might improve or even abate entirely on the gluten-free diet... which might provide some extra incentive for your teen to follow the diet strictly.
ADHD Common in Teens with Celiac Disease
There's a strong link between celiac disease and ADHD — studies have found undiagnosed celiac disease in a high percentage of teens (up to 15%) with diagnosed ADHD. For comparison, celiac disease is found in about 1% of the general population.
In both teens and adults, the gluten-free diet appears to help improve concentration and other symptoms of ADHD, including hyperactivity and impulsiveness, according to some studies.
No studies have looked at teens with non-celiac gluten sensitivity to see if they suffer from more ADHD, but some anecdotal reports from teens and their parents indicate that a gluten-free diet can help with ADHD if the teen in question is gluten-sensitive.
Another study looked at celiac disease and all disruptive behavior disorders, which includes ADHD, oppositional defiant disorder and conduct disorder. That study found 28% of teens with celiac disease had been diagnosed with a disruptive behavior disorder at some point, compared with just 3% of non-celiac teens. "In most cases, these disorders preceded the diagnosis of celiac disease and its treatment with a gluten-free diet," the authors said, adding that celiac teens following the diet suffered from current problems with disruptive behavior disorder at the same rate as non-celiac teens.
Depression Common Among Celiac Teens
There hasn't been as much research involving celiac teens and depression as there has been on gluten and depression in adults, but the research that has been done indicates it's a pretty common problem in teens. For adults, numerous studies show a link between gluten and depression, both for celiac adults and those diagnosed with non-celiac gluten sensitivity.
In the study that looked at disruptive behavior disorders in celiac teens, the researchers also asked about the teens' history of major depressive disorder, and found that 31% of teens reported experiencing an episode of major depression at some point. Only 7% of the non-celiac control subjects reported a history of major depressive disorder.
As with disruptive behavior disorder, going gluten-free seemed to alleviate depressive symptoms and bring levels of the disorder down to those of the control group.
There's evidence from one study that teens with undiagnosed celiac disease and depression have lower-than-normal levels of tryptophan and certain hormones when compared to those without depression, which could lead to problems with mood and sleep (gluten can affect sleep, too).
In that study, teens had a significant decrease in depression after three months on a gluten-free diet. This coincided with easing of the teens' celiac disease symptoms, and also with improvement in their tryptophan levels.
Other Mental Disoders High in Celiac Children
There's medical evidence for slightly higher rates of neurological or psychiatric conditions, such as epilepsy and bipolar disorder, in children who have been diagnosed with celiac disease — one study found such problems in 15 of 835 celiac children, and identified new cases of celiac in seven of 630 children with a neurological disorder.
Problems Living Gluten-Free Could Contribute
Of course, it's possible that gluten-free children and teens might suffer more from some mental disorders — specifically, depression, anxiety and behavioral symptoms — simply because of the difficulties involved in following the gluten-free diet.
In one study, children and teens on a strict gluten-free diet showed more frequent behavioral and emotional symptoms several years after they started the diet. In addition, children and teens in that study seemed to show increased depression and anxiety, starting at the time they went gluten-free.
It's not clear what the results of that study meant, but the authors speculated that the diet was the cause. "The introduction of a gluten-free diet results in a radical change in eating habits and lifestyle of CD [celiac disease] children, and it can be hard to accept and stressful to follow," the authors said.
This stress contributes to anxiety, which surfaces as depression in girls and aggression plus irritability in boys, the authors said. Teens frequently have a tougher time accepting their new dietary restrictions than younger children, they added.
Pynnönen PA et al. Mental disoders in adolescents with celiac disease. Psychosomatics. 2004 Jul-Aug;45(4):325-35.
Pynnönen PA et al. Gluten-free diet may alleviate depressive and behavioural symptoms in adolescents with coeliac disease: a prospective follow-up case-series study. BMC Psychiatry. 2005 Mar 17;5:14.
Ruggieri M et al. Low prevalence of neurologic and psychiatric manifestations in children with gluten sensitivity. Journal of Pediatrics. 2008 Feb;152(2):244-9. Epub 2007 Nov 19.