5 types of insomnia identified
Scientists have identified five different types of insomnia, a finding they say paves the way for more targeted treatments and therapies for those who experience the condition.
The subtypes are not based on sleep complaints, such as difficulty falling asleep or early morning awakening, but on differences between personality traits, responses to treatment, life history and risk of depression.
Researchers surveyed over 4300 participants from the Netherlands Sleep Registry, a database of volunteers, who filled out at least one of 34 questionnaires on personality traits, sleep, life events and health history.
In the findings, outlined in the Lancet Psychiatry, of the 1046 who completed more than 10 questionnaires, researchers classified insomnia into the following:
- Type 1: (19%) Highly distressed insomnia disorder. This group had high pre-sleep arousal and reduced subjective happiness compared with other respondents, scoring highly on many distressing traits, such as neuroticism and feeling down or tense.
- Type 2: (31%) Moderately distressed but reward-sensitive insomnia disorder. These people still display intact responses to pleasurable emotions.
- Type 3: (15%) Moderately distressed but reward insensitive. This group is primarily characterised by reduced positivity, with positive rumination and experience of pleasure more reduced in this than any other subtype.
- Type 4: (20%) Slightly distressed but with high reactivity to their environment and life events. Life events induced severe and long lasting insomnia in this group.
- Type 5: (15%) Slightly distressed with low reactivity. This group’s sleep was less affected by these life events and past traumas.
The identified subtypes would enable more targeted treatments, allowing for improved cognitive, emotional and behavioural interventions, say the researchers from the Netherlands Institute for Neuroscience.
“For example, because a meditation intervention lowers pre-sleep arousal, this treatment could particularly be recommended for people with insomnia disorder of subtypes 1, 2, and 3, which are characterised by high pre-sleep arousal,” they write.
“Interventions that aim to improve positive effect and happiness could be evaluated for people with insomnia subtypes 3 and 5, who showed a disproportional reduced positive effect or experience of pleasure.
“Finally, sleep problems related to childhood adversity, which was most prevalent among participants with subtypes 1 and 4, could require trauma therapy rather than CBT for insomnia only.”
More information: Lancet Psychiatry 2019.