Study links abnormal sleep and schizophrenia for the first time

A study by Oxford researchers of schizophrenia patients has found a link between sleep disruption and schizophrenia independent of medication and social isolation.

The study was the first of its kind in that it looked at the sleep-wake patterns of schizophrenia patients in the community rather than in hospital and over a period of weeks rather than a period of days.

Researchers suggest that the stabilization of sleep-wake patterns may be important in the treatment of schizophrenia and that a stabilized pattern could help patients become less social isolated.

Head of the research group Professor Russell Foster said: “For a long time people have noted that sleep is disrupted in mental health but it has always been assumed to be associated with medication or the fact that they are socially isolated and, as a result, it has been largely dismissed.”

Foster continued: “We have now shown in humans that there is a profound disruption of sleep wake timing. It is the first time that this has been quantified in a cohort of patients. It also seems to be independent of the drugs that they are on and independent of any form of social isolation, such as the lack of a job.”

According to Foster the most important thing to note about sleep-wake timings is that they are “more than just the inconvenience of not sleeping at the appropriate time of day. They have been associated with a whole raft of additional problems.”

These problems are not only social issues of isolation and difficulty in interaction but include immune dysfunction, cognitive disruption and metabolic abnormalities.

“If you can stabilize sleep-wake in these patient groups then you will hopefully mitigate, and maybe even eliminate, some of the comorbid (secondary) pathologies that you find in mental health.”

Second year experimental psychology student Roseanna Sharville said: “Like food and water, sleep is crucial for all living, breathing things. Intuitively, therefore, it certainly seems possible that long-term sleep disturbances could cause severe physical and mental health problems.”

The importance of the findings is supplemented by Foster’s statement that “one in every hundred members of the public is likely to have schizophrenia”.

“The mental health burden to the economy is greater than the cancer burden. Since its effects are long term and impact on family and carers also,” he continued. “We haven’t had any major innovation in mental health in years.”

Foster described possible methods of stabilizing sleep-wake patterns, which involve “trying to impose a temporal order on these individuals” by “stabilizing the light dark cycle and stabilizing the time that they eat”, as well as the use of drugs such as melatonin, which has been “shown under certain circumstances to stabilize sleep-wake in certain individuals with conditions where sleep can be disrupted, such as bilateral eye loss, but might also apply to patients with schizophrenia”.

The study has also has raised a much bigger picture about the nature of the link between mental health problems and sleep-wake abnormalities.

Foster notes how “most people ask ‘Is it cause and effect?’, but I don’t think you can really think about it in that way any longer. I think you have to think about it as common neurotransmitter pathways that are being affected.”

Foster describes a follow up study on mice where gene abnormalities previously linked to schizophrenia are created in mice to see whether “you would also have a big affect upon the sleep wake profile of the mouse and in the paper that has just been accepted, that is exactly what we see.”

The results of the work are not only applicable to schizophrenic patients but are “part of big and really exciting picture”.

According to Foster, the study is also the basis for a big initiative to look at “sleep-wake timings in mental health generally”, with preliminary data suggesting that “we might be able to use sleep as a predictor of impending psychiatric illness. If you have an early indicator then there is chance of going in early”.

Sharville said how the study would either “have led to a breakthrough in the study of this, and other, mental disorders”, or will have “encouraged the treatment of sleep difficulties in schizophrenic patients, no doubt improving the lives of the many suffering from this debilitating, and often terrifying, disorder.”