Sleep disturbances in children with ADHD : a study conducted at Hazrat

Introduction Attention deficit hyperactivity disorder (ADHD) is one of the commonest disorders seen in Child and Adolescent Psychiatry services. ADHD is associated with comorbid conditions such as emotional problems, aggression and oppositional behaviors, specific learning disorders and sleep problems Aims The aim of the present study was to compare sleep problems in children with ADHD with that of a control group.


Introduction
Attention deficit hyperactivity disorder (ADHD) is one of the commonest disorders seen in Child and Adolescent Psychiatry services.ADHD is characterised by inattention, impulsivity and hyperactivity (1,2).The symptoms of ADHD last until adulthood in 65% of cases (3,4).According to a systematic review of the epidemiology of ADHD in Iran, Tehran has the highest prevalence of ADHD (20%), while Sanandaj has the lowest prevalence (2.8%) (5).
ADHD is associated with comorbid conditions such as emotional problems, aggression, oppositional behaviours, specific learning disorders and sleep problems (6,7).Irregular or disturbed sleep is not classified in the DSM IV (8).Sleep problems in children with ADHD can have an impact on the disease and pose a challenge for both parents and professionals (9).
Studies have shown that 25 -50% of children with ADHD have sleep problems (10,11).The types of sleep problems include insomnia, parasomnia , restless leg syndrome, jerky movements , nightmares, inadequate sleep, somnolence, day time sleepiness and low quality of sleep (12)(13)(14).Despite the high prevalence of sleep problems in children with ADHD, physicians usually treat inattention and hyper activity, and do not pay much attention to the treatment of sleep disorders.Improvement of sleep in children with ADHD results in improvement of the condition (11).
Several studies have described the epidemiology of ADHD in Iran , but these have not looked at sleep problems in these children (15,16).The aim of the present study is to compare sleep problems in children with ADHD with that of a control group.

Results
The ADHD group consisted of 80 boys and 10 girls with a mean age of 9.1 years (SD1.6).Control group consisted of 40 boys and 50 girls with mean age of 8.0 years (1.5).
Sex distribution was different in cases and controls.Female to male ratio in ADHD group was 1:8 and in the control group 1:0.8.This was because of higher prevalence of ADHD in boys.Because the control group was selected from an outpatient paediatric clinic, the female: male ratio was similar among controls.The rate of sleeping alone in children with ADHD is significantly lower than in the control group (figure 1) (p<0.001).There was significant difference between the two groups in the duration of sleep, sleep latency and waking up time during holidays and school days.
Routine bed time during school days in the ADHD and control groups is shown in figure2.The number of children with ADHD who slept after 11pm on school days (p=0.03) and slept after midnight during holidays (p< 0.001) was significantly higher than in the control group.

Discussion
Sleep disturbances were significantly more in children with ADHD compared the control group in 22 out of 44 categories.Sleeping alone was less frequent in children affected by ADHD and they slept later during school days and holidays compared to the control group.This can be due to higher anxiety, phobia or oppositional defiant disorder.It is also known that medication used to treat ADHD such as stimulants can cause sleep disturbance.
Other studies have shown some impairment in duration of sleep, sleep latency and awakening time in children with ADHD (17)(18)(19) .A systematic review of sleep Sleep disturbance in children with ADHD disturbances also showed different duration of sleep and sleep latency.There were changes in the stages of sleep and sleep insufficiency in children with ADHD (20).The parents of our patients reported fatigue on waking up, day time sleepiness and lack of deep sleep in children with ADHD.This can be interpreted as a change in the sleep structure.
We found no difference in sleep latency between the two groups.A study by Hvolby et al on 206 children aged 5-11 years, show that long sleep latency and irregularity in sleep pattern in ADHD group are higher than in the control group (17).
It was reported in our study that children with ADHD breathe through the open mouth during the day time more than the control group.In a study in Taiwan, it has been shown that ADHD is associated with respiratory problems during sleep, day time sleepiness, napping, sleep irregularity and parasomnias (20).Our patients showed higher sleepiness but parasomnias like talking during sleep and sleepwalking was not significantly different.
In this study, pain or jerking of feet during sleep was significantly more in children with ADHD.This can be due to restless leg syndrome.However this was elicited as a response to one question and the diagnosis should be confirmed by a comprehensive clinical evaluation.
Although refusing to go to bed can be due to early insomnia, it also could be due to oppositional behaviour, fear or anxiety which is associated with ADHD.These findings are consistent with other research that restless leg syndrome, overactivity and respiratory problems during sleep and early insomnia are more common in children with ADHD (18).
Children in ADHD group were more likely to experience dysphoric mood on waking up.This may be due to mood dysregulation in ADHD.
Rituals associated with sleeping, fear of sleeping alone and fear of darkness in children with ADHD may be due to comorbid anxiety and sense of insecurity.This study had several limitations.It assessed sleep problems using a questionnaire.A clinical evaluation is necessary for a comprehensive assessment of sleep problems.We were also not able to assess the impact of stimulants used to treat ADHD on sleep.

Conclusions
Sleep disturbances are commoner in children with ADHD than in the control group.This is known to affect quality of life and functioning of the patient and family negatively.Future studies should assess the association of severity of ADHD symptoms, functioning level and adherence to treatment, with sleep disturbance in children with ADHD.

AFig. 1
Fig. 1 Comparison of sleeping arrangements Fig. 2 Routine bedtime during school days

Table 1 -
Sleep related behaviours in children with ADHD and controls