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25-09-2011 | Psychology | Article

Sleep-wake disturbances increased in schizophrenia patients with mostly positive symptoms


Free abstract

MedWire News: Results from a Portuguese study suggest that schizophrenia patients with predominantly positive symptoms (SZP) have more disturbed sleep-wake cycles than those with predominantly negative symptoms (SZN).

Patients with schizophrenia frequently experience sleep problems, but little is known about the effects of predominantly positive or negative symptoms on sleep in such patients, explain Pedro Afonso (Lisbon Psychiatry Hospital Center) and colleagues.

To investigate, and to assess the effect of sleep disturbance on quality of life (QoL) in such patients, the team studied 23 outpatients with schizophrenia who were aged between 19 and 52 years.

The Positive and Negative Syndrome Scale (PANSS) was used to divide the patients into two groups consisting of those with SZP (n=11) or SZN (n=12).

Sleep-wake cycle disturbance was assessed using 24-hour wrist-actigraphy over a 7-day period, and quality of sleep and QoL were assessed using the Pittsburgh Sleep Quality Index (PSQI) and the World Health Organization Quality of Life - Abbreviated version (WHOQOL), respectively.

The researchers found that 64% of SZP patients had an irregular sleep-wake cycle compared with 33% of those with SZN.

Both groups had a mean PSQI score of more than 5, which is considered as poor sleep quality. However, SZP patients had a higher mean PSQI score than SZN patients, at 7.7 versus 6.2.

Furthermore, SZP patients had poorer scores in all four WHOQOL domains (physical, psychological, social, and environmental) compared with SZN patients.

Nevertheless, none of these differences in sleep and QoL between the groups reached statistical significance, the researchers note.

However, there were significant negative correlations between PANSS subscales scores and WHOQOL and PSQI scores, indicating that higher symptom levels correlate with lower self-reported QoL and worse quality of sleep.

Afonso and team conclude: "Our results show that there is a trend for more disrupted sleep-wake patterns and circadian activity rhythms in schizophrenia patients with predominant positive symptoms."

They add: "Our results support the hypothesis that poor sleep may worsen QoL in schizophrenia patients. In clinical practice, psychiatrists should give more attention to sleep complaints in schizophrenia since that can have a negative impact in the quality of life of these patients."

By Mark Cowen

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