Insomnia that is a result of a stressful situation may go away on its own over time or when the factor causing stress is no longer present, but for some people insomnia continues even after things improve. So, although some factors may have started problems with insomnia, it is likely that the harmful habits you developed to cope with the insomnia are keeping the insomnia going long after the stressful situation has passed.
Perpetuating factors are common habits and behaviours which people adopt to cope with insomnia which in effect keep insomnia going over time such as irregular sleep schedule, doing activities in bed other than sleep or sex, sleeping in on the weekends, taking long naps in the afternoon. While those habits and behaviours often are initiated to compensate for sleep loss (and can feel refreshing initially), they often disturb sleep-wake cycles in the long run. For example, if you take naps you will use build up "sleep pressure". By the end of the day, the build-up sleep pressure will not be as high since you already used some part of it by taking naps. This could result in difficulties with falling asleep or staying asleep. Additionally, sleeping in and taking naps can mess-up our internal body clock (24 our rhythm). If we dont adhere to a regular sleep-wake schedule, our bodies have a harder time to know when it is time sleep and to be awake, which results in longer wake times and increased sleepiness during the day.
Even if the precipitating factors (the things which triggered the insomnia in the first place) are kept under control, perpetuating factors can still make the sleep problem worse and prevent recovery. The longer you have had your sleep problem, the more likely it is that perpetuating factors are helping to maintain or worsen your insomnia symptoms.
One of the objectives of the programme, therefore, is to help you minimise the influence perpetuating factors have on your sleep.