You’re feeling very sleepy

Just thinking that they’ve not had much sleep could interfere with the daytime functioning of imsomniacs, regardless of whether they actually had enough sleep or not.

Twenty-two students (average age 21 years) with primary insomnia were recruited by Christina Semler and Allison Harvey at Oxford University. All had experienced at least three nights’ sleep disturbance per week for the past month.

For three nights, the students’ sleep was measured using a sensitive gadget that records how much its wearer moves around. Each morning, an electronic display that the students thought was connected to this gadget, told them how well they had slept. But in fact the display was controlled by the researchers, so that they could trick the students into thinking they’d had a good or bad night’s sleep, regardless of how well they’d actually slept.

On days that the students were led to believe they’d had a poor night’s sleep, they reported having more negative thoughts (e.g. “I can’t cope today”), feeling more sleepy, performing more sleep-related monitoring (e.g. noticing aching muscles/ sore eyes), and resorting to more compensatory behaviours (e.g. taking a daytime nap). That’s despite the fact that the actual quality of their sleep didn’t vary significantly between days they were given positive or negative feedback about their sleep.

Together with past research showing imsomniacs often sleep much better than they realise, these findings suggest it could be their anxiety about not sleeping well, rather than a lack of sleep per se, that causes or worsens the daytime impairments so often reported by imsomniacs.

If these results can be replicated with a clinical sample, the authors said, then “…consideration should be given to teaching insomnia patients to lend less credence to their subjective perception of sleep. And the adverse consequences, for daytime functioning, of concluding that they’ve not obtained enough sleep should be emphasised”.

Semler, C.N. & Harvey, A.G. (2005). Misperception of sleep can adversely affect daytime functioning in insomnia. Behaviour Research and Therapy, 43, 843-856.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.