Zheng W, et al. - The prevalence of insomnia symptoms and their socio-demographic correlates were investigated in patients treated at medical outpatient clinics affiliated with four general hospitals in Guangzhou, a large metropolis in southern China. Participants, including 4399 consecutive patients, via completing standardized questionnaires provided data regarding insomnia and its socio-demographic correlates. Findings revealed a common occurrence of insomnia symptoms among patients attending medical outpatient clinics in Guangzhou. Thereby suggesting the need for increasing awareness of sleep hygiene measures, regular screening and psychosocial and pharmacological interventions for insomnia in China.