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

pain). Lentz et al (1999) revealed that after three nights of disrupted stage four (deep)
sleep, participants reported increased pain sensitivity. However, this finding was not
replicated in a similar study by Older (1998). Onen et al (2001) found that only total
sleep deprivation (and not specifically stage four or REM sleep deprivation), was
associated with increased pain sensitivity. The inconsistent findings between these
studies may, however, be a reflection of the lack of statistical power in the three studies
which only included between 9 and 13 participants (Smith & Haythornthwaite, 2004).
Generalisation of the findings for people with chronic sleep disturbance may also be
difficult, as the effects of acute induced sleep deprivation may not be directly
comparable to the effects of chronic poor sleep quality (Smith & Haythornthwaite,
2004).
Using a different approach, Chiu (2005) investigated pain sensitivity in 424 participants
who completed a questionnaire about their sleep quality, and revealed that those who
reported experiencing sleep difficulties were significantly associated with increased
pain sensitivity, as measured by dolorimetry. These findings were subsequently
supported in a similar study of patients with rheumatoid arthritis (Lee et al., 2009)
where higher sleep disturbance reported using the MOS-SS was significantly associated
with increased pain sensitivity using dolorimetry. This suggests that pain and sleep are
linked, although the cross-sectional nature of the studies prevents any sense of causality
being explored.
Further evidence of the links between sleep and pain is revealed through the high
prevalence of self-reported poor sleep quality in patients with chronic pain conditions.
Although the percentage of patients with poor sleep quality does vary between chronic
pain conditions, the percentage of people with chronic pain reporting poor sleep ranges
between 50-70% (Morin, Gibson, & Wade, 1998; Pilowsky, Crettenden, & Townley,
1985; Smith, Perlis, Smith, Giles, & Carmody, 2000), with one study revealing up to
89% of patients reporting at least one difficulty with sleep (McCracken & Iverson,
2002). These are substantially higher rates than those reported in the general population
(23-56%) (Leger et al., 2008).
Poor sleep quality has consistently been found to correlate significantly with
perceptions of pain severity in a number of chronic pain conditions (Pilowsky et al.,
1985). McCracken (2002) revealed that in a sample of 287 participants, who completed
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