Understanding insomnia through cognitive modelling.
Cognitive models of insomnia have received growing support in recent years and are embraced by the current diagnostic framework. Many people with insomnia report that mental events, such as intrusive thoughts or a racing mind, prevent them from achieving or maintaining sleep. Dysfunctional cognition may play an important role in perpetuating insomnia, with many individuals with psychophysiological insomnia reporting a distorted perception of sleep. Neurocognitive studies have indicated that high-frequency EEG activity associated with cognitive processes is enhanced in patients with insomnia at or around sleep onset, which may distort the individual's judgement about sleep initiation and duration. A subtype of psychophysiological insomnia has been proposed--attention-intention-effort (AIE) syndrome--that takes into consideration the interaction between behavioral and cognitive factors in the development and maintenance of insomnia. A series of studies from the University of Glasgow Sleep Centre using cognitive probe tasks has provided insight into this pathway, particularly with regard to the role of attention bias towards sleep stimuli in mediating insomnia. Further research is required to explore the cortical correlates of attention bias, investigate AIE as a potential causal mechanism of insomnia and examine AIE in other insomnia groups.