C-reactive protein alterations in bipolar disorder: a meta-analysis

Area of Science:

• Neuroscience
• Psychiatry
• Immunology

Background:

• Growing evidence suggests a link between bipolar disorder (BD) and inflammation.
• Abnormal levels of acute-phase C-reactive protein (CRP) are implicated in BD.
• CRP is a key marker of low-grade inflammation and a risk factor for other diseases.

Purpose of the Study:

• To estimate the association between C-reactive protein (CRP) levels and bipolar disorder (BD).
• To investigate subgroup differences in CRP levels based on mood phase and treatment.
• To synthesize existing research on CRP and BD through a meta-analysis.

Main Methods:

• A systematic literature search was conducted across major databases (MEDLINE, EMBASE, PsycINFO, ISI Web of Science) up to June 2013.
• Eleven English language studies involving 1,618 subjects were included after screening.
• Data were extracted by two independent reviewers, and random-effects models were used for meta-analysis.

Main Results:

• Overall, patients with bipolar disorder (BD) exhibited significantly elevated C-reactive protein (CRP) levels compared to controls.
• CRP levels were significantly higher in manic and euthymic phases of BD, but not in the depressed phase.
• CRP levels showed no association with lithium or antipsychotic medication use.

Conclusions:

• This meta-analysis provides robust support for an association between elevated CRP levels and bipolar disorder (BD).
• Increased CRP levels indicate low-grade inflammation, which is a risk factor for cardiovascular and malignant diseases.
• Measuring CRP levels may hold clinical relevance for managing bipolar disorder patients.