HTML Heading: Study Shows Sleep Spindles May Regulate Anxiety in People with PTSD
A new study has found that sleep spindles, which are brief bursts of brain activity during one phase of sleep, may play a role in regulating anxiety in individuals with post-traumatic stress disorder (PTSD). These findings challenge previous research suggesting that spindles can heighten intrusive and violent thoughts in people with PTSD. The study was published in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging on May 3, 2023.
Researchers from the UCSF Department of Psychiatry and Behavioral Sciences, the Weill Institute for Neurosciences, and the San Francisco VA Medical Center conducted the study. They enrolled 45 participants who had experienced combat or noncombat trauma, with about half having moderate symptoms of PTSD and the other half having milder symptoms or being asymptomatic.
The researchers focused on studying spindles during non-rapid eye movement 2 (NREM2) sleep, which is the phase of sleep when spindles mainly occur. This phase accounts for approximately 50% of total sleep.
During the study, the participants attended a “stress visit” where they were shown images of violent scenes, such as accidents, war violence, and human and animal injury or mutilation. They then had a lab-monitored nap about two hours later. Anxiety surveys were conducted immediately after exposure to the images and after the nap when recall of the images was tested. The researchers compared anxiety levels in the stress visit to a control visit without exposure to violent images.
The researchers found that spindle rate frequency was higher during the stress visit than during the control visit, indicating that stress influenced spindle-specific sleep rhythm changes. Notably, participants with greater PTSD symptoms experienced a reduction in anxiety after the nap, suggesting that increased spindle frequency influenced anxiety levels.
The study raises questions about whether the therapeutic effect of spindles would be the same if sleep occurred days or weeks after trauma. However, the researchers believe that interventions can be developed to trigger spindles associated with NREM2 sleep, benefiting individuals with stress and anxiety disorders.
The potential use of prescription drugs, like Ambien, to induce spindles is an area for further study. The researchers acknowledge the need to determine if medication-induced spindles can replicate the full range of brain processes associated with naturally occurring spindles.
Electrical brain stimulation is another area of interest for researchers. They suggest that transcranial electrical stimulation or targeted memory reactivation, which involves using cues like odors or sounds during experimental sessions and replaying them during sleep, could potentially induce spindles.
In the absence of such interventions, the researchers recommend following good sleep hygiene practices as a way to maximize the benefits of spindles after a stressful episode. This zero-cost and easy approach can ensure entering sleep phases appropriately.
The researchers’ next project involves studying the role of spindles in the consolidation and replay of intrusive and violent memories several weeks after trauma exposure.
In conclusion, the study highlights the potential role of sleep spindles in regulating anxiety in individuals with PTSD. The findings challenge previous research and offer potential avenues for non-invasive interventions and further investigation into the use of prescription drugs and electrical stimulation to promote spindles. Following good sleep hygiene is also recommended to maximize the benefits of spindles. Future research will focus on their role in the consolidation and replay of traumatic memories.