Sleep disturbances are common complains among schizophrenia patients. Based on these subjective complaints, treatment often involves hypnotic and/or anxiolytic medications with disturbing side effects that increase patients' drug load. Most hypnosedatives are prescribed based on subjective complaints, but little information is published on the relationship between self-report and recorded sleep in this population.

The present study examined the correlation between subjective and objective evaluation of sleep measures among schizophrenia patients compared with age- and gender-matched controls.

The sample comprised two groups: 30 schizophrenia patients (mean age=48.50, SD=12.45; 17 M, 13 F) and 30 age- and gender-matched controls (mean age= 48.56, SD=12.54; 17 M, 13 F). Subjects subjectively evaluated their sleep patterns using two qualitative reports–the Mini Sleep Questionnaire (MSQ), and Pittsburgh Sleep Quality Index (PSQI), and one quantitative report–the Technion Sleep Questionnaire (TSQ). Additionally, subjects' sleep was continuously monitored for a week with a wrist actigraph (Ambulatory Monitoring, Inc.).

Analysis revealed no significant correlations between subjective and objective measures of sleep in all participants. Interestingly, significant interactions were found between estimation type of the discrepancy (overestimate vs. underestimate) and schizophrenia existence (schizophrenia patients vs. controls) on discrepancy of sleep efficiency [F(1,51)=6.2, p<0.05], sleep percentage [F(1,54)=8.86, p<0.01] and minutes of wake after sleep onset [F(1,51)=9.24, p<0.01]; meaning that schizophrenia patients display greater discrepancies than controls.

The findings indicate that subjective reports among schizophrenia patients are unreliable, and argue for objectively evaluating sleep in this population before prescribing sleep medications.