Lack of sleep seen to cause sluggish cognitive tempo (SCT) in adolescents with attention deficits

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It is esti­mat­ed that up to 75% of youth with ADHD have sleep prob­lems. And, exper­i­men­tal stud­ies that manip­u­late sleep quan­ti­ty have demon­strat­ed a causal link between sleep and ADHD behav­ior in children.

How­ev­er, there has been no pri­or work in which sleep dura­tion has been manip­u­lat­ed in ado­les­cents diag­nosed with ADHD. Evi­dence of a causal link between sleep quan­ti­ty and ADHD symp­toms in ado­les­cents would pro­vide addi­tion­al sup­port for includ­ing sleep as an inter­ven­tion tar­get in teens with ADHD, espe­cial­ly for those with known sleep difficulties.

This issue was addressed in a study pub­lished online recent­ly in the Jour­nal of the Amer­i­can Acad­e­my of Child and Ado­les­cent Psychiatry.

The New Study

Par­tic­i­pants were 72 14–17-year olds diag­nosed with ADHD. The study involved a 3‑week sleep pro­to­col with an exper­i­men­tal cross over design. After a one-week base­line peri­od, youth par­tic­i­pat­ed in one-week of sleep restric­tion and one-week of sleep extension.

Dur­ing the restric­tion week, teens adjust­ed their bed­time to allow no more than 6.5 hours in bed. Dur­ing the exten­sion week, bed­time was adjust­ed to pro­vide 9.5 hours in bed. The order of restric­tion and exten­sion weeks was coun­ter­bal­anced across participants.

Sleep was mea­sured using a wrist-mount­ed acti­graph. This con­firmed that par­tic­i­pants obtained 1.6 more hours of sleep on aver­age dur­ing the exten­sion week com­pared to the restric­tion week.

Day­time sleepi­ness and ADHD symp­toms were mea­sured at the end of each week using rat­ing scales com­plet­ed by par­ents and by adolescents.

Par­ents and teens also com­plet­ed rat­ings of slug­gish cog­ni­tive tem­po (SCT), a set of atten­tion­al symp­toms reflect­ed by men­tal con­fu­sion, day­dream­ing, and ‘slowed’ behav­ior and think­ing. SCT over­laps with, but is not iden­ti­cal to, the inat­ten­tive symp­toms that char­ac­ter­ize ADHD.

Final­ly, par­ents also com­plet­ed rat­ings of their teen’s oppo­si­tion­al behavior.

The Results

As expect­ed, large dif­fer­ences in day­time sleepi­ness were found in both par­ent and ado­les­cent rat­ings, with greater sleepi­ness report for the sleep restric­tion week. Ado­les­cents also report­ed more day­time nap­ping dur­ing this week.

Par­ents report­ed that their teen showed sig­nif­i­cant­ly more atten­tion prob­lems and oppo­si­tion­al behav­ior dur­ing the sleep restric­tion week com­pared to the sleep exten­sion week.; they also observed large dif­fer­ences relat­ed to slug­gish cog­ni­tive tem­po. Dif­fer­ences in hyper­ac­tive-impul­sive behav­ior dur­ing restric­tion and exten­sion weeks were not found.

The teens them­selves did not report dif­fer­ences in atten­tion prob­lems between the restric­tion and exten­sion weeks. How­ev­er, they report­ed more symp­toms of slug­gish cog­ni­tive tem­po and more hyper­ac­tive-impul­sive behav­ior dur­ing the sleep restric­tion week.

The Key Takeaway

This study pro­vides clear exper­i­men­tal evi­dence that how much teens with ADHD sleep has a sig­nif­i­cant impact on their atten­tion and behav­ior. An addi­tion­al 1.6 hours per night — the aver­age dif­fer­ence in sleep dur­ing restric­tion and exten­sion weeks — had impacts that were dis­cernible to par­ents and, for some out­comes, to teens themselves.

The fact that these results are not sur­pris­ing does not dimin­ish their poten­tial sig­nif­i­cance. Increas­ing sleep is a safe, free, inter­ven­tion that can make a mean­ing­ful difference.

What is sur­pris­ing, how­ev­er, is that that assess­ing sleep and inter­ven­ing where indi­cat­ed is not done for many youth with ADHD. While the impact of increas­ing sleep did not have as large an effect, on aver­age, as med­ica­tion, there is no rea­son not to include sleep assess­ment and inter­ven­tion for near­ly all youth with ADHD. There is vir­tu­al­ly no cost to doing this and it can make a difference.

The study would have been stronger if data was also obtained from teach­ers to learn whether the ben­e­fits that par­ents observed were also observed at school. This is par­tic­u­lar­ly true since par­ents were not ‘blind’ to sleep con­di­tion and their rat­ings may thus have been influ­enced by knowl­edge of whether their child was in the restric­tion or exten­sion por­tion of the study. This could be addressed in sub­se­quent research.

This lim­i­ta­tion not with­stand­ing, the study high­light a safe, inex­pen­sive, and poten­tial­ly valu­able tar­get for inter­ven­tion in youth with ADHD that may often be overlooked.

– Dr. David Rabin­er is a child clin­i­cal psy­chol­o­gist and Direc­tor of Under­grad­u­ate Stud­ies in the Depart­ment of Psy­chol­o­gy and Neu­ro­science at Duke Uni­ver­si­ty. He pub­lish­es the Atten­tion Research Update, an online newslet­ter that helps par­ents, pro­fes­sion­als, and edu­ca­tors keep up with the lat­est research on ADHD.

The Study in Context: