Throwing new light on sleep

benefits that sleep brings until they can’t sleep well any more,’ Lockley and Foster comment in Sleep: A Ver y Short Introduction.1 It’s a lesson millions of people learn the hard way. About 10% of us report chronic insomnia, for example.2 Many more – about a third – suffer from one or more of the 75 or so clinical sleep disorders at some time in our lives.1 At least 80% of people with depression or schizophrenia and many of those with Alzheimer’s or Parkinson’s disease experience sleep disturbances.1 Indeed, hypersomnia and excessive daytime sleepiness can be one of the first signs of parkinsonism. (This probably reflects dysfunctions in neural networks and neurotransmitters common to sleep and parkinsonism.)2 Sleep disordered breathing independently predicts stroke risk and worsens the outcomes of stroke and epilepsy.2 Yet while the health implications of disrupted sleep are increasingly clear, sleep remains, arguably, the most enigmatic of our basic biological drives.