Hohagen F, Käppler C, Schramm E, Riemann D, Weyerer S, Berger M
Psychiatric Department, University of Freiburg, Germany.
Sleep. 1994 Sep;17(6):551-4.
The present study investigated the temporal stability of insomnia patterns during a 4-month study period, classifying insomnia as sleep-onset insomnia, sleep-maintaining insomnia or insomnia with early morning awakening. In a longitudinal study design, 2,512 general practice attenders were investigated at the time of the first inquiry (T1) with a questionnaire. Four months later (T2), all patients complaining of difficulties in initiating and/or maintaining sleep and/or early morning awakening (n = 328) were again contacted by mail and received the same questionnaire as at T1. According to the reported symptoms, patients were assigned to the different subtypes of insomnia. The diagnosis at T1 was then compared with the diagnosis at T2 4 months later. Only about half of all patients who complained of difficulties in initiating sleep at T1 still exclusively reported sleep-onset insomnia 4 months later, whereas the remaining patients were distributed to different subtypes. The stability of sleep-maintaining insomnia and insomnia with early morning awakening was even lower. Comorbidity with a somatic or psychiatric disorder at T1 and change in hypnotic treatment did not account for the instability of the respective subgroup of insomnia. These findings illustrate that cross-sectional studies focusing on subtypes of insomnia, e.g. sleep-onset insomnia, may lead to erroneous results.
本研究在为期4个月的研究期间调查了失眠模式的时间稳定性，将失眠分为入睡困难型失眠、睡眠维持困难型失眠或早醒型失眠。在一项纵向研究设计中，在首次询问时（T1），用问卷对2512名全科门诊患者进行了调查。4个月后（T2），通过邮件再次联系了所有抱怨入睡和/或维持睡眠困难及/或早醒的患者（n = 328），并向他们发放了与T1时相同的问卷。根据所报告的症状，将患者分配到不同的失眠亚型。然后将T1时的诊断与4个月后的T2时的诊断进行比较。在T1时抱怨入睡困难的所有患者中，4个月后只有约一半的患者仍仅报告入睡困难型失眠，而其余患者则分布到不同亚型。睡眠维持困难型失眠和早醒型失眠的稳定性甚至更低。T1时存在躯体或精神疾病合并症以及催眠治疗的改变并不能解释相应失眠亚组的不稳定性。这些发现表明，关注失眠亚型（如入睡困难型失眠）的横断面研究可能会导致错误的结果。
