• Potential Biomarker: Serum levels of lipid hydroperoxide (LOOH)
• Type: Serum
• Relevance: The serum levels of lipid hydroperoxide have been considered as a potential biomarker for anxiety disorders among children (Ceylan et al., 2014).
• Potential Biomarker: Nighttime Fears (NF)
• Type: Behavioral
• Relevance: Nighttime Fears (NF) may be a potential behavioral biomarker for anxiety vulnerability, fears, and behavioral problems among children, especially those preschool children of 4 -6 years old (Kushnir et al., 2014).
• Potential Biomarker: BAIAP3 SNPs (AA for rs2235632, TT for rs1132358)
• Type: Genetic variants
• Relevance: The genetic polymorphisms of BAIAP3 (BAI1 Associated Protein 3) may be the potential biomarkers for anxiety among women and benzodiazepine abuse among men (Wojcik et al., 2013).
• Potential Biomarker: Cone of Direct Gaze: CoDG (“range of eye gaze angles judged as being directed at oneself”)
• Type: Psychophysical
• Relevance: CoDG has been suggested as a potential psychophysical biomarker for social anxiety disorder (Jun et al., 2013).
• Potential Biomarkers: Abnormal cerebrospinal fluid (CSF) Aβ42 and t-tau levels
• Type: Cerebrospinal fluid (CSF)
• Relevance: Abnormal levels of cerebrospinal fluid (CSF) Aβ42 and t-tau can be the potential biomarkers for the symptoms of anxiety, agitation and irritability among those with mild cognitive impairment (MCI) (Ramakers et al., 2013).
• Potential Biomarker: Electroencephalographic activities (P1 activation, N2 activation)
• Type: Neurophysiological
• Relevance: The Electroencephalographic activities may be the potential biomarkers for the outcomes of cognitive behavioral therapy (P1) and responses (N2) among anxious children (Hum et al., 2013).
• Potential Biomarkers: Higher HDL, free fatty acids (FFA), dehydroepiandrosterone-sulfate (DHEA-S), substance P
• Type: Plasma biochemical markers
• Relevance: Higher levels of HDL, FFA, DHEA-S, and substance P may indicate anxiety and degraded mood among females (Lieberman et al., 2012).
• Potential Biomarkers: Elevated dark-enhanced startle, sympathetic system activation
• Type: Psychopathological markers
• Relevance: Elevated dark-enhanced startle and sympathetic system activation may be a marker for anxiety among children with abused mothers (Jovanovic et al., 2011).
• Potential Biomarker: Higher cortisol levels in saliva
• Type: Saliva biochemical markers
• Relevance: Higher cortisol levels in saliva may be a potential marker for psychosomatic halitosis (PH) (oral malodor) with anxiety (Fukui et al., 2010).
• Potential Biomarker: Aversive learning, aversive conditioning
• Type: Behavioral
• Relevance: Aversive learning may be a potential biomarker for anxiety disorders among children (Craske et al., 2008).
• Potential Biomarker: CO2 sensitivity
• Type: Psychophysical
• Relevance: The CO2 sensitivity may be a potential biomarker for social anxiety disorder (SAD) among young adults (Schmidt et al., 2008).
• Potential Biomarkers: Inflammation and coagulation markers in men: C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), homocysteine, fibrinogen levels; in women: CRP, white blood cell counts, IL-6, homocysteine, fibrinogen levels
• Type: Inflammation and coagulation markers
• Relevance: Inflammatory and coagulation markers including CRP and IL-6 may be associated with anxiety among men (19-89 years old) and women (18 to 84 years old) (Pitsavos et al., 2006).
• Potential Biomarker: Glyoxalase-I protein
• Type: Protein marker in the brain areas
• Relevance: The glyoxalase-I protein may be a potential biomarker for anxiety- and depression-like behavior, as identified in mice models (Krömer et al., 2005).
• Potential Biomarker: Anxiety sensitivity (phrenophobia, fear of physical arousal)
• Type: Psychological
• Relevance: Phrenophobia may be a potential biomarker for anxious symptoms among young psychiatric inpatients between 9-17 years old (Joiner et al., 2002).
• Potential Biomarker: Cholesterol levels
• Type: Biochemical marker
• Relevance: Cholesterol levels have been associated with anxiety and depression among a normal population in a primary care setting (Rafter et al., 2001).
• Potential Biomarkers: Higher levels of CD16 (natural killer) cells; CD19 cells (B lymphocytes), human leukocyte antigen (HLA)-DR-presenting cells, HLA-DR and CD19 surface markers (B lymphocytes with surface HLA-DR)
• Type: Circulating lymphocyte phenotypic markers
• Relevance: Higher levels of natural killer cells, B lymphocytes, and HLA-DR-presenting cells have been associated with anxiety disorders, panic disorder, and generalized social phobia (Rapaport et al., 1998).
• Potential Biomarker: Plasma levels of glucose, cortisol and prolactin
• Type: Plasma biochemical markers
• Relevance: The plasma levels of glucose, cortisol and prolactin may be related to anxiety caused by physiology examination (EPh) and psychology (EPs) examination among female medical students (Armario et al., 1996).
• Potential Biomarker: Frontal midline theta activity
• Type: Physiological
• Relevance: Frontal midline theta activity has been considered as a potential biomarker for anxiety among male university students (Mizuki et al., 1989).
Armario A, Marti O, Molina T, de Pablo J, Valdes M. Acute stress markers in humans: response of plasma glucose, cortisol and prolactin to two examinations differing in the anxiety they provoke. Psychoneuroendocrinology. 1996 Jan;21(1):17-24.
Ceylan MF, Guney E, Alisik M, Ergin M, Dinc GS, Goker Z, Eker S, Kizilgun M, Erel O. Lipid peroxidation markers in children with anxiety disorders and their diagnostic implications. Redox Rep. 2014 Mar;19(2):92-6. doi: 10.1179/1351000213Y.0000000082.
Craske MG, Waters AM, Lindsey Bergman R, Naliboff B, Lipp OV, Negoro H, Ornitz EM. Is aversive learning a marker of risk for anxiety disorders in children? Behav Res Ther. 2008 Aug;46(8):954-67. doi: 10.1016/j.brat.2008.04.011.
Fukui M, Hinode D, Yokoyama M, Yoshioka M, Kataoka K, Ito HO. Levels of salivary stress markers in patients with anxiety about halitosis. Arch Oral Biol. 2010 Nov;55(11):842-7. doi: 10.1016/j.archoralbio.2010.07.014.
Hum KM, Manassis K, Lewis MD. Neurophysiological markers that predict and track treatment outcomes in childhood anxiety. J Abnorm Child Psychol. 2013 Nov;41(8):1243-55. doi: 10.1007/s10802-013-9755-7.
Joiner TE Jr, Schmidt NB, Schmidt KL, Laurent J, Catanzaro SJ, Perez M, Pettit JW. Anxiety sensitivity as a specific and unique marker of anxious symptoms in youth psychiatric inpatients. J Abnorm Child Psychol. 2002 Apr;30(2):167-75.
Jovanovic T, Smith A, Kamkwalala A, Poole J, Samples T, Norrholm SD, Ressler KJ, Bradley B. Physiological markers of anxiety are increased in children of abused mothers. J Child Psychol Psychiatry. 2011 Aug;52(8):844-52. doi: 10.1111/j.1469-7610.2011.02410.x.
Jun YY, Mareschal I, Clifford CW, Dadds MR. Cone of direct gaze as a marker of social anxiety in males. Psychiatry Res. 2013 Nov 30;210(1):193-8. doi: 10.1016/j.psychres.2013.05.020.
Krömer SA, Kessler MS, Milfay D, Birg IN, Bunck M, Czibere L, Panhuysen M, Pütz B, Deussing JM, Holsboer F, Landgraf R, Turck CW. Identification of glyoxalase-I as a protein marker in a mouse model of extremes in trait anxiety. J Neurosci. 2005 Apr 27;25(17):4375-84.
Kushnir J, Gothelf D, Sadeh A. Nighttime fears of preschool children: a potential disposition marker for anxiety? Compr Psychiatry. 2014 Feb;55(2):336-41. doi: 10.1016/j.comppsych.2013.08.019.
Lieberman HR, Kellogg MD, Kramer FM, Bathalon GP, Lesher LL. Lipid and other plasma markers are associated with anxiety, depression, and fatigue. Health Psychol. 2012 Mar;31(2):210-6. doi: 10.1037/a0026499.
Mizuki Y, Suetsugi M, Imai T, Kai S, Kajimura N, Yamada M. A physiological marker for assessing anxiety level in humans: frontal midline theta activity. Jpn J Psychiatry Neurol. 1989 Dec;43(4):619-26.
Pitsavos C, Panagiotakos DB, Papageorgiou C, Tsetsekou E, Soldatos C, Stefanadis C. Anxiety in relation to inflammation and coagulation markers, among healthy adults: the ATTICA study. Atherosclerosis. 2006 Apr;185(2):320-6.
Rafter D. Biochemical markers of anxiety and depression. Psychiatry Res. 2001 Aug 5;103(1):93-6.
Ramakers IH, Verhey FR, Scheltens P, Hampel H, Soininen H, Aalten P, Rikkert MO, Verbeek MM, Spiru L, Blennow K, Trojanowski JQ, Shaw LM, Visser PJ; Alzheimer’s Disease Neuroimaging Initiative and DESCRIPA Investigators. Anxiety is related to Alzheimer cerebrospinal fluid markers in subjects with mild cognitive impairment. Psychol Med. 2013 May;43(5):911-20. doi: 10.1017/S0033291712001870.
Rapaport MH. Circulating lymphocyte phenotypic surface markers in anxiety disorder patients and normal volunteers. Biol Psychiatry. 1998 Mar 15;43(6):458-63.
Schmidt NB, Timpano KR, Buckner JD. Fear responding to 35% CO(2) challenge as a vulnerability marker for later social anxiety symptoms. J Psychiatr Res. 2008 Jul;42(9):763-8.
Wojcik SM, Tantra M, Stepniak B, Man KN, Müller-Ribbe K, Begemann M, Ju A, Papiol S, Ronnenberg A, Gurvich A, Shin Y, Augustin I, Brose N, Ehrenreich H. Genetic markers of a Munc13 protein family member, BAIAP3, are gender specifically associated with anxiety and benzodiazepine abuse in mice and humans. Mol Med. 2013 Jul 24;19:135-48. doi: 10.2119/molmed.2013.00033.