Schizophrenia 27 Oct, 2016 Read Time: 4 mins

Sleep and schizophrenia are intimately linked

Since sleep regulation involves many neurotransmitter systems and brain circuits, it is likely that the mechanisms generating normal sleep overlap with those that maintain mental health. This would explain why disturbed sleep and schizophrenia are so intimately linked. This was the essence of the seminar given at the Lundbeck Institute on 17th April 2015 by Russell Foster, director of the Sleep and Circadian Neuroscience Unit at the University of Oxford, UK.

Sleep disturbance is common in serious mental illness, and schizophrenia is no exception. It is widely accepted that schizophrenia disrupts sleep and circadian rhythms. But it also seems that disturbances of sleep can precede severe mental illness and may even help cause it.1

Sleep problems: common and important in psychosis1

  • Sleep is less regular, may occur at any time of the day or night, and may be too much or too little.
  • It can be hard to get sleep or stay asleep.
  • Symptoms of fear or anxiety often affect sleep.
  • A change in sleep may precade onset of psychosis or relapse.
  • Sleep problems cause other major health problems - both physical and mental.

References

  1. Ruhrmann S, et al. Prediction of psychosis in adolescents and young adults at high risk: results from the prospective European prediction of psychosis study. Arch Gen Psych.2010;67(3):241-51.
    Among 245 people at high risk of psychosis and presumed to be in a prodromal phase, sleep disturbance contributed to a model that predicted transition to psychosis over 18-month follow-up. Other predictors included positive symptoms, bizarre thinking, level of functioning in the past year and years of education. 

  2. Wulff K, et al. Sleep and circadian rhythm disruption in schizophrenia. Br J Psychiatry. 2012;200(4):308-16.
    Despite relatively well controlled symptoms and treatment with newer antipsychotic medications, people with schizophrenia (n=20 outpatients) showed significant disruption of sleep and circadian cycles when compared to healthy controls (n=21). These differences are not accounted for by absence of the discipline imposed by paid employment since – just as among patients - none of the control subjects was in work. People with schizophrenia reported that their sleep was of poorer quality, showed markedly greater variability in the timing of sleep and waking, took longer to fall asleep (mean 34 vs 19 minutes), and spent longer asleep (mean sleep duration 8.2 vs 6.1 hours). In 50% of schizophrenia patients, the timing of sleep was out of synchrony with the day/night cycle. In many of these patients, circadian rhythms in melatonin were also abnormal, indicating that their bodies’ internal rhythm was not well synchronised with the day/night cycle. It has been suggested that sleep disruption in schizophrenia may be a side effect of antipsychotic medication, but this study found no relationship between circadian abnormalities and drug type or dose.

  3. Wulff K, et al. Sleep and circadian rhythm disruption in psychiatric and neurodegenerative disease. Nat Rev Neurosci. 2010;11(8):589-99.

  4. Oliver PL, et al. Disrupted circadian rhythms in a mouse model of schizophrenia. Curr Biol. 2012;22(4):314-9.
    The mechanistic basis for the association between circadian rhythm disruption and schizophrenia is unknown. The authors presented a link between disruption of circadian activity cycles and synaptic dysfunction in an animal model of neuropsychiatric disease. They investigated the circadian phenotype of blind-drunk (Bdr), a mouse model of synaptosomal-associated protein (Snap)-25 exocytotic disruption that displays schizophrenic endophenotypes. The rest and activity rhythms of Bdr mice are phase advanced and fragmented under a light/dark cycle. This is similar to the disturbed sleep patterns in schizophrenia. The authors proposed that the Bdr circadian phenotype is due to disruption of synaptic connectivity within the SCN that alters critical output signals.

  5. Myers E, et al. Cognitive behavioural treatment of insomnia in individuals with persistent persecutory delusions: a pilot trial. J Behav Ther Exp Psychiatr. 2011;42(3):330-6.
    This study evaluated the treatment of insomnia in individuals with persecutory delusions to establish whether reducing insomnia will reduce paranoid delusions. In 15 patients who received cognitive behavioural intervention for insomnia (CBT-I) intervention, levels of insomnia and persecutory delusions were significantly reduced post-treatment and at the one-month follow-up. Levels of anomalies of experience, anxiety and depression were also reduced. It was concluded that CBT-I can be used to treat insomnia in individuals with persecutory delusions and also lessens the delusions.

  6. Peigneux P, et al. Are spatial memories strengthened in the human hippocampus during slow wave sleep? Neuron. 2004;44(3):535-45.
    Using cerebral blood flow measurements, this study demonstrated that hippocampal areas that are activated during route learning in a virtual town are also activated during subsequent slow wave sleep. In fact, the amount of hippocampal activity during slow wave sleep correlated with route retrieval performance the following day. The authors proposed that learning-dependent modulation of hippocampal activity during sleep leads to plastic changes that account for subsequent recall performance.