From the Journals

A blood test to diagnose bipolar disorder?


 

TOPLINE:

A blood test that measures biomarkers linked to manic symptoms can accurately identify patients with bipolar disorder (BD) who were previously misdiagnosed with major depressive disorder (MDD), new research shows. Investigators state that the test could identify up to 30% of patients with BD when used on its own and could be even more effective when combined with a standardized psychometric assessment.

METHODOLOGY:

  • In the proof-of-concept study, investigators sought to identify biomarkers to accurately identify BD, which is frequently misdiagnosed as MDD because of overlapping symptoms and the lack of objective diagnostic tools.
  • The study included 241 participants (70% female; mean age, 28 years) from the U.K.-based Delta Study who had been diagnosed with MDD within the past 5 years and had depressive symptoms as assessed with the Patient Health Questionnaire-9 (score ≥ 5).
  • Participants completed an online questionnaire that included questions from the Mood Disorder Questionnaire and the Warwick-Edinburgh Mental Well-Being Scale and were asked to return a dried blood spot (DBS) fasting blood sample.
  • Investigators analyzed the DBS samples for 630 metabolites and contacted participants by phone to establish diagnoses at 6 and 12 months using the World Health Organization World Mental Health Composite International Diagnostic Interview.

TAKEAWAY:

  • Investigators used a panel of 17 biomarkers to correctly identify 67 (27.8%) participants with BD who had been previously misdiagnosed with MDD. They confirmed MDD in the remaining 174 patients.
  • The biomarkers used in the test were correlated primarily with lifetime manic symptoms and were validated in a separate group of 30 patients.
  • The identified biomarker panel provided a mean cross-validated area under the receiver operating characteristic curve of 0.71 (P < .001), with ceramide d18:0/24:1 emerging as the strongest biomarker.
  • Combining biomarker readouts with patient-reported data significantly improved the performance of diagnostic models based on extensive demographic data and information from the Patient Health Questionnaire and Mood Disorder Questionnaire (P = .03 for all).

IN PRACTICE:

“The added value of biomarkers was particularly evident in scenarios where data on psychiatric symptoms were unavailable and at intermediate diagnostic thresholds, suggesting that biomarker tests may especially benefit patients who do not report their symptoms and whose diagnoses are uncertain,” the authors write.

SOURCE:

Jakub Tomasik, PhD, of the University of Cambridge (England), led the study, which was published online in JAMA Psychiatry. Stanley Medical Research Institute and Psyomics funded the study.

LIMITATIONS:

Data on confounding factors such as diet and blood pressure were missing. In addition, investigators noted that the sample mostly comprised White Internet users and was not representative of all individuals with BD.

Dr. Tomasik has a patent pending for DBS blood biomarkers. Other disclosures are noted in the original article.

A version of this article first appeared on Medscape.com.

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