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SLEEP AND HEALTH 33
occurred when children were in sports areas and it is noteworthy that 25% of all
injuries were caused through intentional violence by other pupils.
2.3.1.12 Use of sleeping pills
Several studies demonstrated that the use of sleeping pills is common among children
and that paediatricians are prone to prescribe these medications. Twenty-five percent
of firstborn infants had been given “sedatives” by 18 months (Ounsted and
Hendrick, 1977). A research study into parental reports of 11 000 preschool children
showed that 12% took psychoactive drugs, most commonly for sleep: 39%
daily and 60% intermittently for 1–2 years (Kopferschmitt et al., 1992). Another
study (Trott et al., 1995) revealed that 35% of prescriptions for children less than a
year old were for sleep disturbances and that sleep disturbances were also the most
common reason for prescribing medications to preschool children (23%). Two
French surveys on adolescents showed that 10–12% of the respondents reported use
of prescription or over-the-counter drugs for sleep disturbances (Patois, Valatz and
Alperovitch, 1993; Ledoux, Choquet and Manfredi, 1994). Recently it has been
reported that of 671 community-based United States paediatricians, 75% had recommended
over-the-counter and 50% prescription medicines for insomnia during
the past 6 months (Owens, Rosen and Mindell, 2003). In addition, an Italian survey
showed that pharmacological treatment for sleep problems was prescribed during
the past 6 months by 58.54% of paediatricians and by 61.21% of child neuropsychiatrists
(Bruni et al., 2004).
2.3.2 BASIC INDIVIDUAL FACTORS: GENDER AND AGE
Gender shows itself to be an important predictor of disturbed sleep in virtually all
epidemiological studies (Karacan et al., 1976; Bixler, Kales and Soldatos, 1979;
Ancoli-Israel and Roth, 1999; Leger et al., 2000; Sateia et al., 2000). On the other
hand, there does not seem to be much of a difference in polysomnographical parameters
between males and females, except for the former losing SWS with increasing
age and having slightly reduced sleep efficiency also with increasing age (Williams,
Karacan and Hursch, 1974; Hume, Van and Watson, 1998). Ehlers and Kupfer
(1997) timed the start of differences between genders to between 20 and 40 years.
Spectral analysis also indicates slightly larger amounts of low frequency activity in
females (Dijk, Beersma and Bloem, 1989; Dijk, Beersma and Van den Hofdakker,
1989). In addition, men seem to run a higher risk of morbidity and mortality related
to sleep problems than women (Nilsson et al. 2001). The inconsistency between
polysomnography and subjective measures has not been resolved but it may be
important that most polysomnographical studies have controlled for anxiety and
depression. Thus, it is conceivable that the higher level of subjective complaints in
women reflects a higher prevalence of anxiety. The latter is a speculation, however.
A confounding factor in gender comparisons is that phases in female biological
cycles are also usually controlled for in polysomnographical studies, meaning that
potential effects of, for example, menstruation, may not receive their proper weight.
A recent review has gone through the literature in this area (Moline et al., 2003). It
found that the luteal phase of the menstrual cycle is associated with subjective sleep
problems, but polysomnographical studies have not supported this. Pregnancy
affects sleep negatively as early as in the first trimester and the effects mainly involve
awakenings and difficulties getting back to sleep. Napping is a frequent coping
method. The post-partum period is often associated with severe sleep disruption,
mainly due to feeding and comforting the infant. There seems to be some relation
between sleep disruption and post-partum mood, but nothing is known about the
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