Blood test for the diagnosis of depression

Depression can be diagnosed with the help of biomarkers

04/17/2012

Depression affects not only adults, but may also affect children, with mental illness often difficult to distinguish from general mood swings. US researchers have therefore determined several biomarkers that can be detected in a blood test and provide clear evidence of depression.

A blood test can be used to reliably diagnose childhood and adolescent depression, write First author Kathleen Pajer of Northwestern University in Chicago and her colleagues in the latest issue of the journal „Translational psychiatry“. The US researchers have defined a number of biomarkers that can be detected in the blood and provide information about a possibly existing depression.

Blood test for the diagnosis of depression
The blood test could in the opinion of the US researchers soon replace the complex diagnosis of depression disorders of children and adolescents. The severe mental illness also affects people under the age of 25 years, but with them is particularly difficult to diagnose, write Pajer and colleagues. Overall, about one percent of the population is already affected under the age of 12 years, the US researchers continue. For the adolescents, the mental illness often causes serious damage to their development and bring with it an increased risk of physical illness, explain the scientists. They are also prone to drug use, have difficulties in social adjustment and are at increased risk of suicide, Pajer and colleagues report.

Biomarkers allow objective diagnosis of depression
So far, the diagnosis of depression in both adults and adolescents relies on patient self-control and clinical observation, which, according to the US researchers, provides relatively unreliable (subjective) findings. Biological markers could provide objective guidance in diagnosis, however „despite 30 years of research“ To date, no clear biomarkers have been identified, as the US scientists write in their journal article. Kathleen Pajer and colleagues therefore devoted themselves to the search for reliable biological characteristics that can be used to diagnose depression. They focused their research on indicators that point to genetic disposition and stress as the most common causes of depression.

Also, anxiety disorders can be identified by biomarkers
Based on animal experiments and a first study with 14 depression patients and 14 healthy volunteers, the US researchers identified eleven blood markers, which may indicate a depression in childhood. Based on the blood markers, a reliable diagnosis can be made, which also allows a clear distinction in the direction of general mood swings - as they often occur in adolescents - write the US scientists. In addition, 18 other biomarkers have been identified that allow a distinction between pure depression and depression with concomitant anxiety disorder, Pajer and colleagues further. Five of the eleven defined biomarkers, according to the researchers, come from the heritable area and six are linked to chronic stress. The won „Pilot data suggest that our approach of clinically valid diagnostic panels of blood markers“ In early depression, the diagnostic options significantly improved and has the potential, „to advance individualized therapy strategies“, write the US scientists. For the first time it is possible based on the biomarker to objectively prove the mental illness.

Further studies on biomarkers in depression required
According to study director Eva Redei from Northwestern University, those are discovered „Eleven genes may just be the tip of the iceberg“ and it may be possible to identify numerous other biomarkers that are useful in diagnosing depression. In any case, the current study provides the proof, „that it is actually possible to diagnose depression via the blood“, emphasized the study director. The limits of „current study are the relatively small sample size and the limited number“ of biomarkers, so the limitation of the authors. Overall, the US researchers, according to their own assessment, however „a novel approach to identifying potential biomarkers“ for depression in children and adolescents. In further studies, the biomarkers must now „a large sample of adolescents with depression“ be tested to confirm their validity, explains Kathleen Pajer. Researchers expressed confidence that biomarkers will provide objective evidence of depression in the future. (Fp)

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Picture: Rainer Sturm