Bipolar disorder is a mental health condition that causes extreme mood swings, from manic highs to depressive lows. It can be a difficult condition to diagnose, as the symptoms can overlap with other conditions, such as depression, anxiety, ADHD, etcetera.
A new study from the University of Cambridge suggests that some day a blood test could help to diagnose bipolar disorder more accurately and quickly. The test looks for biomarkers that are associated with the condition.
Over 3000 individuals were enlisted, and each of them undertook an extensive online evaluation about their mental well-being including more than 600 questions designed to identify those individuals who had a history of major depression (unipolar depression) and those who had a history of bipolar mood disorders. The questionnaire consisted of 635 questions split into 6 modules: 1) demographic information, 2) manic and hypomanic symptoms, 3) depressive symptoms, 4) personality traits, 5) psychiatric history, and 6) comorbid psychiatric symptoms.
A subset of the 3000 individuals completed a phone based interview using the World Health Organization World Mental Health Composite International Diagnostic Interview (CIDI) version 3.0. The interview was used to establish the diagnosis of either major depression (unipolar depression) or bipolar disorder.
From the pool of individuals who successfully finished the internet evaluation, approximately 1000 individuals were chosen to submit a dried blood sample obtained through a straightforward finger prick. The researchers then utilized mass spectrometry to analyze over 600 metabolites present in the samples.
Metabolites measured were mostly either amino acids or amino acid metabolites or lipids and their metabolites.
The overall sample was broken into two groups:
- Group 1, the discovery cohort. The discovery cohort consisted of 241 participants with current depressive symptoms who had been diagnosed with major depression within the prior 5 years, whose diagnosis was either confirmed as unipolar depression or altered to bipolar disorder type 1 by the CIDI. The metabolite results from this group were used to develop, using machine based learning, a model that had the best ability to distinguish between those individuals with major depression and those with bipolar disorder.
- Group 2, the validation cohort. The validation cohort included 30 participants experiencing depressive symptoms at the time of sample collection and professionally diagnosed with either BD or MDD during the study’s 1-year follow-up period.
How well did the metabolite test do in distinguishing bipolar and unipolar individuals?
The research used the AUC ROC method for evaluating the usefulness of the test. In the discovery cohort and the validation cohort the AUC ROC value was roughly the same at roughly 0.72. What does this mean qualitatively? Generally, an AUC ROC of 0.7 to 0.8 is considered acceptable, 0.8 to 0.9 is considered excellent, and more than 0.9 is considered outstanding. In other words, the test was at the low end of acceptably accurate. However, when combined with other data (the MDQ, PHQ-9 and demographic information) the AUC ROC increased to 0.89 or just below outstanding.
In summary, the blood test would have to be used in conjunction with other diagnostic tools, such as psychiatric assessments, but it could significantly improve the accuracy of bipolar disorder diagnosis.
The blood test is still in its early stages of development, but it has the potential to revolutionize the way that bipolar disorder is diagnosed. A simple blood test could make it possible to diagnose bipolar disorder more quickly and accurately, which would lead to earlier treatment and better outcomes for patients.
Benefits of a simple blood test for bipolar disorder
There are several potential benefits to a simple blood test for bipolar disorder, including:
Earlier diagnosis: A blood test could help to diagnose bipolar disorder earlier than current methods, which could lead to earlier treatment and better outcomes for patients.
More accurate diagnosis: A blood test could help to improve the accuracy of bipolar disorder diagnosis, especially in people with complex or atypical symptoms.
More objective diagnosis: A blood test could provide a more objective measure of bipolar disorder than current methods, which are based on subjective reports from patients and clinicians.
Reduced stigma: A blood test could help to reduce the stigma associated with bipolar disorder by making it clear that the condition is a biological disorder, not a sign of weakness or personal failure.
How a blood test for bipolar disorder could work
The blood test for bipolar disorder is still in its early stages of development, but it is thought to work by detecting biomarkers in the blood that are associated with the condition. Biomarkers are molecules that can be measured in the blood or other bodily fluids and that can indicate the presence or severity of a disease.
A simple blood test for bipolar disorder could be a major breakthrough in the diagnosis and treatment of this condition. A blood test could help to diagnose bipolar disorder earlier, more accurately, and more objectively than current methods. It could also help to reduce the stigma associated with bipolar disorder.
This study had several limitations, including missing data on potential confounding factors, such as diet and blood pressure, a predominantly White patient population of internet users previously diagnosed with MDD who are not representative of all patients with BD, the reliance on information self-reported by participants, and the small validation cohort.
More research is needed to validate the blood test for bipolar disorder and to determine how it can be best used in clinical practice. However, the results to date are promising and suggest that a blood test for bipolar disorder could be available in the not-too-distant future.
University of Cambridge. (2023, October 25). Simple blood test can help diagnose bipolar disorder. ScienceDaily. Retrieved October 26, 2023 from www.sciencedaily.com/releases/2023/10/231025162958.htm
Simple blood test can help diagnose bipolar disorder. (2023, October 25). University of Cambridge. https://www.cam.ac.uk/research/news/simple-blood-test-can-help-diagnose-bipolar-disorder
Tomasik J, Harrison SJ, Rustogi N, et al. Metabolomic Biomarker Signatures for Bipolar and Unipolar Depression. JAMA Psychiatry. Published online October 25, 2023. doi:10.1001/jamapsychiatry.2023.4096