SKINREMS-A New Method for Assessment of the Niacin Skin Flush Test Response in Schizophrenia

Diagnostic value of niacin skin blunting response in adolescent patients with depression

OBJECTIVE

To investigate the differences in the niacin skin flushing response of adolescent depressed patients and healthy adolescents and its diagnostic value in adolescent depression.

METHODS

Thirty-eight cases of acute episodes of depression in unmedicated adolescents and 47 age- and sex-matched healthy controls were included as study subjects, and sociodemographic and clinical data were collected, all of which were stimulated with six concentration gradients (up to 60 mmol/L, followed by sequential 3-fold gradient dilution to a minimum of 0.25 mmol/L) of niacin solution on the forearm skin, and the skin flushing area was applied as an assessment index.

RESULTS

The total area of redness of the skin in response to niacin was significantly lower in the adolescent depression group than in the healthy adolescent group (Z=-3.36, p = 0.001) and was able to distinguish the adolescent depression group from the healthy adolescent group (area under curve = 0.713, sensitivity 51.1%, specificity 83.2%).

CONCLUSIONS

Niacin sensitivity is reduced in adolescent depressed patients, and the niacin skin flush response has potential clinical value as a diagnostic biomarker for adolescent depression.

Niacin Skin Flush Backs-From the Roots of the Test to Nowadays Hope

The niacin skin flush test (NSFT) is a simple method used to assess the content of fatty acids in cell membranes and is a possible indicator of factors hidden behind various outcomes in patients. The purpose of this paper is to determine the potential usefulness of NSFT in mental disorder diagnostics along with the determination of factors that may affect its results. The authors reviewed articles from 1977 onwards, focusing on the history, variety of methodologies, influencing factors, and proposed mechanisms underlying its performance. Research indicated that NSFT could be applicable in early intervention, staging in psychiatry, and the search for new therapeutic methods and drugs based on the mechanisms of NSFT action. The NSFT can contribute to defining an individualized diet for patients and prevent the development of damaging disease effects at an early stage. There is promising evidence for supplementation with polyunsaturated fatty acids, which have a beneficial influence on the metabolic profile and are effective even in the subclinical phase of the disease. NSFT can contribute to the new classification of diseases and a better understanding of certain mental disorders' pathophysiology. However, there is a need to establish a validated method for assessing the NSFT results.

A potential objective marker in first-episode schizophrenia based on abnormal niacin response

The lack of objective diagnostic markers has long been a challenge in the clinical management of schizophrenia (SZ). The current bivariate cut-offs method is an objective quantification of niacin skin flush abnormality (NFA) for identifying the SZ subgroup. However, the sensitivity of approximately 30% limits the application of NFA as a marker for detecting SZ. A laser Doppler flowmeter was employed to test the niacin skin-flushing response in 123 patients with first-episode psychosis including first-episode SZ (FES, n = 82) and psychotic bipolar disorders (PBP, n = 41), and non-psychiatric comparisons (NPC, n = 80). We modified the bivariate cut-offs using a combination of the niacin concentration corresponding to the half-maximal blood flow response (EC₅₀) and a new quantitative indicator called the overall trend area (OTA). The NFA used this study method predicted FES in the NPC group with 57% sensitivity, 89% specificity, and 73% accuracy compared to the 28% sensitivity, 91% specificity, and 59% accuracy of the existing method. This novel method could discern FES from the PBP group with an accuracy of 62%, compared with the 45% of the old method. In addition, we also discuss whether the bivariate cut-offs were occasional by adjusting the cut-offs threshold. The experimental results showed that the sensitivity and specificity were most stable when using the study method. The study indicates that NFA using modified bivariate cut-offs may be a potential objective marker in FES, and the niacin skin test could be feasible for early diagnosis and treatment of SZ.