Washington: More than 8.4 million adults in the United States tend to sleepwalk, showing a link between nocturnal wanderings and psychiatric disorders such as depression and anxiety.
Researchers from Stanford University School of Medicine, who conducted the study, said it "underscores the fact that sleepwalking is much more prevalent in adults than previously appreciated".
Maurice Ohayon, professor of psychiatry and behavioural sciences at Stanford, who led the study, said sleepwalking can have serious consequences. Episodes can result in injuries to the wanderer or others and lead to impaired psychosocial functioning, the journal Neurology reports.
It is thought that medication and certain psychological and psychiatric conditions can trigger sleepwalking, but the exact causes are unknown. Also unclear to experts in the field is the prevalence, according to a Stanford statement.
The researchers wrote: "Apart from a study we did 10 years ago in the European general population, where we reported a prevalence of two percent sleepwalking, there are nearly no data regarding the prevalence of nocturnal wanderings in the adult general population. In the United States, the only prevalence rate was published 30 years ago."
For this study, the first to use a large, representative sample of the US general population to demonstrate the number of sleepwalkers, the researchers also aimed to evaluate the importance of medication use and mental disorders associated with sleepwalking.
Ohayon and colleagues secured a sample of 19,136 individuals from 15 states and then used phone surveys to gather information on participants` mental health, medical history and medication use.