Sick and Tired: Understanding and Managing Sleep Difficulties in ...

particularly some pain relieving medications that contain high levels of caffeine. As a
stimulant, caffeine can lead to poor sleep quality particularly if ingested close to
bedtime. Even moderate amounts of caffeine can affect sleep. For example in one study,
adult men were given a 200mg single dose of caffeine (equivalent to one to two cups of
regular coffee) or a non active placebo before 7.30 in the morning and were asked not to
consume any further caffeine products for the remainder of the day. The results revealed
that on the day participants were given the caffeine, they experienced reduced sleep
efficiency (total sleep time/time in bed x 100), total sleep time, and increased latency to
stage two sleep (Landolt, Werth, Borbely, & Dijk, 1995). This suggests that even a
relatively small dose of caffeine can have a considerable effect on sleep.
Bootzin and Nicassio (1978) highlighted the importance of behaviours on sleep quality
in their stimulus control theory. They proposed that over time the sleeping environment
(e.g. the bedroom) becomes associated with wakefulness and other activities un-
associated with sleep. For example, people may also use their bedroom for watching
television, working or using a computer or reading, making the bedroom a stimulating
environment and therefore increasing arousal. If people experience difficulty sleeping
they may also begin to associate being in bed with feeling agitated and frustrated about
not being able to sleep and these associations may therefore prevent sleep onset or
further disrupt sleep.
Amalgamating the research evidence on the factors affecting sleep quality in people
with insomnia, Lundh and Broman (2000) proposed the integrative model of the
interaction between sleep-interfering and sleep-interpreting processes. The four boxes at
the top of Figure 3 (p. 20) represent the sleep interfering processes and the three boxes
at the bottom of Figure 3 highlight the sleep interpretation processes that impact on
sleep quality. As shown by the model, these processes are likely to influence each other
with beliefs about sleep also directly influencing behaviour and cognitive coping
strategies.
19