Sleep quality and neuropsychological functioning in bipolar I disorder

Area of Science:

• Neuroscience
• Psychiatry
• Sleep Medicine

Background:

• Bipolar I disorder (BD-I) is associated with impaired sleep and neuropsychological functioning, hindering recovery.
• The specific impact of poor sleep on cognitive deficits in BD-I remains under-investigated.
• Poor sleep is known to affect cognitive functions like learning, memory, and executive functions in healthy populations.

Purpose of the Study:

• To compare sleep disturbance and neuropsychological functioning between individuals with BD-I and healthy controls (HC).
• To investigate the association between sleep quality and cognitive performance in both BD-I and HC groups.
• To determine if the effect of sleep quality on cognition differs between BD-I and HC.

Main Methods:

• A naturalistic study involving 250 individuals with BD-I and 206 HC.
• Participants completed the Pittsburgh Sleep Quality Index and underwent neuropsychological testing.
• Clinician-administered mood measures were also collected to examine effects of diagnosis and sleep quality on cognitive functioning.

Main Results:

• Individuals with BD-I exhibited poorer sleep quality and deficits in 7 out of 9 neuropsychological domains compared to HC.
• Poor sleep quality correlated with impairments in verbal learning, verbal fluency, processing speed, and interference control.
• The impact of poor sleep on neuropsychological functioning was comparable between the BD-I and HC groups.

Conclusions:

• Individuals with BD-I experiencing poor sleep are more susceptible to verbal learning and executive functioning impairments.
• Findings underscore the importance of assessing and treating sleep disturbances in BD-I for improved cognitive outcomes.
• The study highlights the pervasive effects of poor sleep on cognitive health across different populations.