Sleep Disturbances Affect the Majority of Schizophrenia Patients

Liam Davenport

April 09, 2018

FLORENCE, Italy — A large proportion of schizophrenia patients suffer from a range of sleep disturbances — a finding that shines a light on an underexamined area in major psychiatric disorders.

In a study that included more than 5000 psychiatric patients and 8000 healthy control persons, investigators found that among schizophrenia patients, particularly those aged 18 to 40 years, rates of sleep disturbances were much higher than in the general population.

Led by Minna Torniainen-Holm, PhD, National Institute for Health and Welfare, University of Helsinki, Finland, the researchers found that "disturbed sleep is very common" in patients with schizophrenia; 75% of such patients report having a sleep disturbance of one kind or another.

"They were sleeping long, they were tired, and they had difficulties falling asleep and staying asleep," said Torniainen-Holm.

The findings were presented here at the Schizophrenia International Research Society (SIRS) 2018 Biennial Meeting.

Important Piece of the Puzzle

Torniainen-Holm began her presentation by noting that there has been a lot of focus on physical exercise and diet for patients with schizophrenia, but "I think there is still one piece missing, and I think it could be sleep," she said.

As part of the international Stanley Global Neuropsychiatric Genomics Initiative, the researchers launched the Finnish SUPER (Finnish Study on Genetic Mechanisms of Psychotic Disorders), which aims to recruit 10,000 patients who have major psychiatric disorders by the end of 2018.

In the current study, the investigators focused on 5046 patients aged 18 to 80 years. Of those patients, 2972 had schizophrenia; 640, schizoaffective disorder; 1097, bipolar disorder; and 330, psychotic depression. These patients were compared with 8018 adults from the general population who took part in the Health 2000 study.

Participants completed a self-report questionnaire on sleep. Patients provided information on total sleep time, tiredness, difficulties in getting to sleep without sleep medication, and early-morning or night awakenings.

The team found that 30% of patients aged 18 to 40 years who had schizophrenia or schizoaffective disorder reported sleeping more than 10 hours a day. By comparison, 15% of patients of the same age who had bipolar disorder or psychotic depression slept as much, as did fewer than 1% of the general population of the same age.

Schizophrenia patients were also more likely to report tiredness, difficulties in getting to sleep, and early-morning or night awakenings than the general population of those younger than 60 years. The prevalence was greater in patients with bipolar disorder and in those with psychotic depression.

In all cases, the differences in sleep difficulties became less pronounced in individuals older than 60 years. Long sleep and tiredness decreased in all patient groups. The general population reported an increase in difficulty in getting to sleep and an increase in early-morning or night awakenings.

Torniainen-Holm noted that, despite the findings, many questions remain.

"We have still many things we have to do more research on," she said. "For example, what is the effect of medication on these results? How does illicit drug use affect them, and how about [the fact] that most of the patients are not working?"

Emphasizing the fact that the results are "still very preliminary and our research into sleep is still in its infancy," she said that the role of sleep disturbances in patients with major psychiatric disorders is still not clear. One key question, she said, is, "What could happen if we would improve sleep?"

Benefits of Treatment

A second study, which was also presented at the meeting, suggests that 6 months of treatment not only improved sleep in this patient population but also resulted in improved cognition, weight loss, and reductions in systolic blood pressure.

Using a home-based assessment, Cherrie Galletly, MD, PhD, Discipline of Psychiatry, the University of Adelaide, Australia, and colleagues found that rates of sleep apnea in schizophrenia patients were twice those seen in the general population.

The researchers performed home sleep studies with polysomnography in 30 schizophrenia patients who were being treated with clozapine.

Results revealed that 14 (47%) of the participants had obstructive sleep apnea (OSA), defined as having a score >10 on the Apnea-Hypopnea Index (AHI). Eight (27%) participants had severe OSA, defined as an AHI score >30, which is "twice the prevalence of severe OSA in the general population," the investigators report.

Six patients with severe OSA were offered continuous positive airway pressure (CPAP) treatment. Adherence to the treatment was good — the mean nightly usage was 7.7 hours.

Six months of CPAP was associated with improvements in sleep architecture. The percentage of the night spent in restorative, slow-wave sleep increased from 4.8% to 31.6%, and the percentage of time in rapid eye movement sleep increased from 4.1% to 31.4%.

The mean percentage of the night spent in a hypoxic state, defined as an oxygen saturation <90%, reduced from an average of 27.6% to 2.0%.

In addition, participants experienced an average weight loss of 7.2 kg during the study period, as well as a 12-mmHg reduction in systolic blood pressure.

Patients also experienced improvements in cognitive performance with 6 months of CPAP treatment. The greatest improvements were seen in verbal and working memory and motor skills.

Galletly told Medscape Medical News that it was "very feasible" to assess OSA in schizophrenia patients using home-based screening.

"Patients have been very accepting of it. They've undertaken the screening properly, and they've been interested in the results, because they know they don't sleep well," she said.

She said that the results "surprised us, because they lost weight.... It's very hard to get people with schizophrenia on clozapine to lose weight. Cognitive function is better, energy is better, they're doing more — they're very happy with the outcomes."

For Galletly, one secret of their success in tackling OSA in patients with schizophrenia is that their team includes both respiratory physicians and psychiatrists.

"Also, we've done a lot of research with people with schizophrenia in the community, so we're used to working with that population and engaging with them," she said.

She also believes that they had more success in identifying OSA in patients with schizophrenia because they used home-based screening, rather than the standard screening instruments, such as questionnaires.

These questionnaires, she said, typically rely on questions such as, " 'Does your partner say you snore? Does your partner say that you pause in your sleep?' Of course, most of them don't have partners, so those screening instruments are actually not that much help."

Psychosis Contributor?

Fiona Gaughran, MD, PhD, Institute of Psychiatry, Psychology and Neuroscience, King's College London, United Kingdom, who was not involved in either study, said that sleep is a "very important" issue in schizophrenia.

"There are people talking about insomnia being relevant in the genesis of psychosis, so even at the very early stages, before you have a diagnosis, sleep may be important," she said.

"[Torniainen-Holm] presented that the patients with schizophrenia found it difficult to get to sleep at nighttime, and yet they're sleeping 10 hours a day. When are those 10 hours, and how does that interfere with your ability to get back into educational training or the workforce, if needed? That's something we need to find out a lot more about," Gaughran added.

She also pointed out that the "sleep apnea question is incredibly important because you can do something about it."

She added that systematically assessing sleep may show ways of working with patients to improve sleep hygiene.

"Looking at how you can get sleep into a way that will best support recovery is vital," she said.

No funding for either study has been disclosed. Dr Galletly serves on advisory boards for Janssen-Cilag and Lundbeck. The other investigators have disclosed no relevant financial relationships.

Schizophrenia International Research Society (SIRS) 2018 Biennial Meeting. Poster F165, presented April 6, 2018, and abstract 05.5, presented April 7, 2018.

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