First night effect and reverse first night effect in older adults with primary insomnia: does anxiety play a role?

Objective: The main objective was to examine first night effect (FNE) and reverse first night effect (RFNE) in older insomniacs and the role played by anxiety in these processes.Background: RFNE has been documented in a middle-aged sample of insomniacs, but little research has been done on RFNE or FNE in older insomniacs. Also, a relationship between anxiety and FNE has not been established.Methods: Participants were 77 older adults with primary insomnia (57 females, 20 males). Two consecutive nights of polysomnography (PSG) were conducted, and the state form of the State-Trait Anxiety Inventory was completed each night. Sleep diaries were completed the morning after each (PSG) and for 2 weeks at home.Results: Most participants exhibited a FNE (57%) rather than a RFNE (26%). State anxiety was elevated on PSG night 1 relative to PSG night 2 in the FNE group but not the RFNE group, and the FNE group reported greater home total sleep time. Among FNE participants, self-reported total sleep and sleep efficiency were significantly higher on PSG night 2 than at home.Conclusions: Most older insomniacs show a FNE, but a portion exhibit a RFNE. Elevated anxiety on PSG night 1 may play a role in FNE.