Is Sleepwalking Hereditary? The Genetic Link Explained

Sleepwalking, also known as somnambulism, is a type of parasomnia involving physical behaviors during sleep. It occurs during the non-rapid eye movement (NREM) stages, specifically deep sleep. Individuals may engage in complex actions like walking, talking, or performing other activities, with little to no memory of the event upon waking.

The Genetic Link to Sleepwalking

There is a clear hereditary influence on sleepwalking, with family and twin studies providing strong evidence. Children are significantly more likely to sleepwalk if one or both parents have a history of the disorder.

For instance, a child has approximately three times higher odds of sleepwalking if one parent was a sleepwalker. This likelihood increases to about seven times if both parents have a history of sleepwalking, with prevalence rates reaching over 60% in such cases.

Scientists have identified specific gene variations more common in individuals who sleepwalk, such as the HLA-DQB105 allele. While these genetic factors create a predisposition, their presence does not guarantee sleepwalking episodes.

Environmental and Lifestyle Triggers

While genetics play a role, external and physiological factors can also provoke a sleepwalking episode in predisposed individuals. Disruptions to a consistent sleep schedule, such as sleep deprivation or irregular bedtime routines, are common triggers. Physiological stressors like fever or illness can contribute to an episode.

Psychological factors, including heightened stress, anxiety, or a history of childhood trauma and post-traumatic stress disorder, can increase the likelihood of sleepwalking. Substance use, particularly alcohol consumption before bedtime, can disrupt normal sleep patterns by increasing slow-wave sleep, the stage where sleepwalking typically occurs.

Certain medications, such as zolpidem, quetiapine, various antidepressants, benzodiazepines, and lithium, have also been linked to triggering sleepwalking episodes. Other sleep disorders, like obstructive sleep apnea and restless legs syndrome, can similarly act as triggers due to their impact on sleep cycles.

Sleepwalking Prevalence in Children Versus Adults

Sleepwalking is considerably more common in children than in adults, typically presenting between the ages of 4 and 8 years. Within a 12-month period, approximately 5% to 15% of children experience sleepwalking, in contrast to about 1% to 1.5% of adults. This higher prevalence in younger individuals is often attributed to their developing nervous systems and the greater amount of time they spend in deep NREM sleep.

Most children who sleepwalk will outgrow the condition by their teenage years, often without the need for specific interventions. When sleepwalking begins in adulthood, it is less common and may signal a connection to the environmental or lifestyle triggers previously mentioned. Adult-onset sleepwalking can also be associated with underlying medical conditions, including certain neurological or degenerative brain diseases.

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