Insulin resistance in bipolar disorder: A systematic review of illness course and clinical correlates.
Level 3 - non-randomized controlled study
Systematic review of primarily non-randomized observational/cross-sectional studies
PubMed 37086806 · doi:10.1016/j.jad.2023.04.068
What was done
A systematic review and meta-analysis (PROSPERO CRD42022359259) was conducted across multiple databases through May 2022 to examine neuroimaging, cognition, illness course, and treatment response in individuals with bipolar disorder (BD) with insulin resistance (IR) or impaired glucose metabolism (IGM) compared to euglycemic BD individuals.
What was found
Ten reports were included (n = 1,183). BD patients with IR showed worse composite verbal memory scores, worse executive function, smaller hippocampal volumes, and prefrontal neurochemical alterations compared to euglycemic BD patients. Meta-analyses showed BD patients with IGM were more likely to have a chronic course (k = 2, OR = 2.96, 95% CI 1.69-5.17, p < 0.001), a rapid cycling course (k = 2, OR = 2.88, 95% CI 1.59-5.21, p < 0.001), and a higher rate of poor response to mood stabilizers (k = 2, OR = 6.74, 95% CI 1.04-43.54, p = 0.04). There was a non-significant trend for lower Global Assessment of Functioning scores (k = 5, MD = -4.00, 95% CI -8.23 to 0.23, p = 0.06).
Why it matters
This review links insulin resistance to worse cognitive, structural, illness trajectory, and treatment response outcomes in bipolar disorder, highlighting metabolic health as a potential prognostic factor.
Limits
The included studies were predominantly cross-sectional with small sample sizes, limiting generalizability and causal inference. Meta-analytic findings for illness course and treatment response relied on only two studies each, with wide confidence intervals.
Cited by
- supports In patients with bipolar disorder, insulin resistance is associated with increased rapid cycling, greater treatment resistance, and higher suicidality.