Insulin resistance and outcome in bipolar disorder.
Level 4 - case-series / case-control
Cross-sectional observational study assessing metabolic status and clinical course
PubMed 25323142 · doi:10.1192/bjp.bp.114.152850
What was done
Fasting glucose and insulin were measured in 121 adults with bipolar disorder to diagnose type 2 diabetes and determine insulin resistance. Researchers used the National Institute of Mental Health Life Chart to record the course of bipolar disorder and the Alda scale to determine response to prophylactic lithium treatment. Sensitivity analyses adjusted for body mass index and antipsychotic exposure.
What was found
Patients with bipolar disorder and type 2 diabetes or insulin resistance had significantly higher odds of a chronic course (50% and 48.7% vs. 27.3% in euglycaemic controls; OR = 3.07, P = 0.007) and rapid cycling (38.5% and 39.5% vs. 18.2%; OR = 3.13, P = 0.012). They were also markedly more likely to be refractory to lithium treatment (36.8% and 36.7% vs. 3.2%; OR = 8.40, P < 0.0001). These associations remained statistically significant after adjusting for antipsychotics and body mass index.
Why it matters
This study links metabolic dysfunction to more severe illness trajectories and treatment refractoriness in bipolar disorder, highlighting insulin resistance as a potential target or biomarker for poor lithium response.
Limits
The sample size is relatively small (n = 121), and the observational design prevents establishing causality between insulin resistance and lithium resistance. The abstract does not specify the exact criteria or index used to define insulin resistance.
Cited by
- supports In patients with bipolar disorder, insulin resistance is associated with increased rapid cycling, greater treatment resistance, and higher suicidality.