High salivary alpha-amylase levels in patients with schizophrenia: A pilot study

A Bibliometric Analysis of Clinical Trials on Salivary Biomarkers for Mental Health (2003-2024)

Mental health conditions, such as depression, anxiety, and stress-related disorders, are often difficult to diagnose and monitor using traditional methods. Salivary biomarkers offer a promising alternative due to their non-invasive nature, ease of collection, and the potential to reflect real-time physiological changes associated with mental health. This bibliometric analysis examines 95 clinical trials on stress biomarkers for mental health, published between 2003 and 2024. The field is characterized by extensive collaboration and global participation, involving 593 authors and publications across 73 journals. Despite a consistent annual publication rate, notable increases in 2011, 2014, and 2018 indicate growing research interest. The United States leads in research output, followed by Australia, Germany, and Japan, with Psychoneuroendocrinology being the most prominent journal. Co-occurrence analysis identified nine research clusters, suggesting diverse directions such as the impact of stress-related hormones, circadian rhythms, mindfulness, various therapies, aging, psychological adaptation mechanisms, exercise therapy, anxiety disorders, and the autonomic nervous system on salivary biomarkers. Key terms such as "biomarkers/metabolism," AND "hydrocortisone/metabolism," AND "saliva/metabolism" were central, with significant activity from 2012 to 2018. This analysis highlights a growing focus on the metabolic processes and therapeutic applications of salivary biomarkers in mental health. This bibliometric analysis calls attention to the promising potential of salivary biomarkers to revolutionize mental health diagnostics and treatment through non-invasive methods, fostering interdisciplinary research, technological advancements, and global health improvements.

Associations between saliva alpha-amylase, heart rate variability, saliva cortisol and cognitive performance in individuals at ultra high-risk for psychosis

BACKGROUND

Cognitive impairments are present in individuals at ultra-high risk (UHR) of psychosis and UHR individuals exhibit a hyperactive and dysfunctional HPA-axis. Increasing stress levels could potentially lead to cognitive impairments and no previous studies have examined the association between physiological stress biomarkers and cognition in UHR individuals. This study aims to examine the association between saliva alpha amylase (SAA), heart rate variability (HRV), saliva cortisol, and cognition in UHR individuals.

METHOD

We included 72 UHR individuals, aged 18-40, fulfilling criteria of the comprehensive assessment of at-risk mental state (CAARMS). Cognitive tests indexed the 7 core domains as stated by Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS). Physiological stress levels were observed for one day: saliva was collected at awakening, 30 min and 60 min after awakening and at bedtime. HRV was measured during sleep and before awakening. We used generalized linear model and controlled for multiple testing using false discovery rate (FDR).

RESULTS

Higher levels of SAA were significantly associated with lower cognitive performance in the domains of verbal and visual learning and memory, sustained attention, working memory and global neurocognition looking at unadjusted data. Controlling for FDR visual memory, sustained attention and global neurocognition remained significant associated with SAA. We discovered no associations between cortisol and cognition.

CONCLUSION

Visual learning and memory, sustained attention and global neurocognition remained significantly associated with SAA. This finding supports our hypothesis that an association between abnormal stress biomarkers and impaired cognition might be present in UHR individuals.

The effects of voice content on stress reactivity: A simulation paradigm of auditory verbal hallucinations

OBJECTIVES

Psychosis is associated with increased subjective and altered endocrine and autonomic nervous system stress-reactivity. Psychosis patients often experience auditory verbal hallucinations, with negative voice content being particularly associated with distress. The present study developed a voice-simulation paradigm and investigated the effect of simulated voices with neutral and negative content on psychophysiological stress-reactivity, and the effect of mindful voice-appraisals on stress-reactivity.

METHOD

Eighty-four healthy participants completed the Montreal Imaging Stress Task with simultaneous presentation of one of three randomly allocated auditory stimuli conditions: negative voices, neutral voices or non-voice ambient sounds. Subjective stress-levels and mindful voice-appraisals were assessed using questionnaire measures, and cortisol and α-amylase levels were measured using saliva samples.

RESULTS

ANOVA revealed a significant effect of condition on subjective stress-levels (p = .002), but not cortisol (p = .63) or α-amylase (p = .73). Post-hoc analyses showed that negative voices increased subjective stress-levels relative to neutral voices (p = .002) and ambient sounds (p = .01), which did not differ from each other (p = .41). Mindful voice-appraisals were associated with less distress across conditions (p = .003), although negative voices were also associated with less mindful appraisals (p < .001).

CONCLUSIONS

Negative voice content, rather than voices or auditory stimuli per se, is linked to greater subjective but not physiological stress-reactivity. Mindful appraisals may partially moderate this effect. These findings highlight the importance of voice content for the impact of voice-hearing, and highlight the potential value of mindfulness training to treat voice distress in psychosis.

A Potential Interface between the Kynurenine Pathway and Autonomic Imbalance in Schizophrenia

Schizophrenia is a neuropsychiatric disorder characterized by various symptoms including autonomic imbalance. These disturbances involve almost all autonomic functions and might contribute to poor medication compliance, worsened quality of life and increased mortality. Therefore, it has a great importance to find a potential therapeutic solution to improve the autonomic disturbances. The altered level of kynurenines (e.g., kynurenic acid), as tryptophan metabolites, is almost the most consistently found biochemical abnormality in schizophrenia. Kynurenic acid influences different types of receptors, most of them involved in the pathophysiology of schizophrenia. Only few data suggest that kynurenines might have effects on multiple autonomic functions. Publications so far have discussed the implication of kynurenines and the alteration of the autonomic nervous system in schizophrenia independently from each other. Thus, the coupling between them has not yet been addressed in schizophrenia, although their direct common points, potential interfaces indicate the consideration of their interaction. The present review gathers autonomic disturbances, the impaired kynurenine pathway in schizophrenia, and the effects of kynurenine pathway on autonomic functions. In the last part of the review, the potential interaction between the two systems in schizophrenia, and the possible therapeutic options are discussed.

Psychophysiological stress-reactivity in clinical and non-clinical voice-hearers

BACKGROUND

Psychosis is associated with dysregulation of psychophysiological stress-reactivity, including in subjective, autonomic nervous system (ANS) and hypothalamic-pituitary-adrenal (HPA) parameters.

AIMS

This study investigated whether dysregulated psychophysiological stress-reactivity is specifically associated with auditory verbal hallucinations (AVHs) or psychosis more generally by comparing voice-hearers with and without a need for care.

METHOD

Clinical (n = 20) and non-clinical voice-hearers (n = 23), as well as a healthy control group with no voices (n = 23), were compared on HPA and ANS responses, and subjective reactivity, to a psychophysiological stress paradigm, the socially evaluative cold pressor test.

RESULTS

Measures of HPA function in both clinical and non-clinical voice-hearers diverged from non-voice-hearing controls. Clinical participants showed a blunted peak response compared to both non-clinical groups (p = 0.02), whilst non-clinical voice-hearers showed, at trend-level, reduced cortisol levels during stress exposure compared to both clinical voice-hearers (p = 0.07) and healthy controls (p = 0.07), who unexpectedly did not differ from each other (p = 0.97). Clinical participants showed greater subjective stress levels than both non-clinical groups (p < 0.001), as well as greater anticipatory stress (p = 0.001) and less recovery. There were no differences between groups on parameters of the ANS (all p > 0.05).

CONCLUSIONS

Dysregulated psychophysiological stress-function is present in clinical voice-hearers, and partially discriminates them from non-clinical voice-hearers. Overall, the present findings identified specific potential psychophysiological markers of risk and resilience in auditory verbal hallucinations and need for care.

[Traumatization and Schizophrenic Disorders - A Multidimensional View]

Prevalence of traumatizing of patients with schizophrenia is higher as in the normal community. Meta analyses show significant relationships between traumatic experiences in childhood and psychotic disorders. Patients with schizophrenia as well as those with posttraumatic stress disorder (PTSD) are characterized by brain morphological changes (mygdala und Hippocampus). In these two patient groups, neuroendocrinological disturbances (cortisol und α-amylase) as well as a worse clinical outcome could be additionally found. In the psychodynamic theoretical discussion, there are only few approaches concerning trauma and psychosis. Specifically here, the name of Frieda Fromm-Reichmann should be noted, who already pointed out the great meaning of child traumatization (especially physical and sexual abuse) for the later manifestation of schizophrenia. She also developed first principles of analytic psychosis therapy with the working on the deep life anxiety caused by the trauma in the here and now of the transference situation. It is assumed that schizophrenic disorders and PTSD have to be understood as trauma consequence diseases, which occur in comorbidty in a so far unknown extent.

Oral health, organic and inorganic saliva composition of men with Schizophrenia: Case-control study

BACKGROUND

Schizophrenia (SCZ) presents complex challenges related to diagnosis and clinical monitoring. The study of conditions associated with SCZ can be facilitated by using potential markers and patterns that provide information to support the diagnosis and oral health.

METHODS

The salivary composition of patients diagnosed with SCZ (n = 50) was evaluated and compared to the control (n = 50). Saliva samples from male patients were collected and clinical parameters were evaluated. The concentration of total proteins and amylase were determined and salivary macro- and microelements were quantified by ICP OES and ICP-MS. Exploratory data analysis based on artificial intelligence tools was used in the investigation.

RESULTS

There was a significant increase in the salivary concentrations of Al, Fe, Li, Mg, Na, and V, higher prevalence of caries (p < 0.001), periodontal disease (p < 0.001), and reduced salivary flow rate (p = 0.019) in SCZ patients. Also, samples were grouped into six clusters. As, Co, Cr, Cu, Mn, Mo, Ni, Se, and Sr were correlated with each other, while Fe, K, Li, Ti, and V showed the highest concentrations in the samples distributed in the clusters with the highest association between SZC patients and controls.

CONCLUSIONS

The results obtained indicate changes in salivary flow, organic composition, and levels of macro- and microelements in SCZ patients. Salivary concentrations of Fe, Mg, and Na may be related to oral conditions, higher prevalence of caries, and periodontal disease. The exploratory analysis showed different patterns in the salivary composition of SCZ patients impacted by associations between oral health conditions and the use of medications. Future studies are encouraged to confirm the results investigated in this study.

Autonomic nervous system dysfunction in schizophrenia: impact on cognitive and metabolic health

Schizophrenia (SCZ) is a psychiatric disorder characterized by a wide range of positive, negative and cognitive symptoms, along with an increased risk of metabolic syndrome and cardiovascular disease that contribute to a 15-20-year reduced life expectancy. Autonomic dysfunction, in the form of increased sympathetic activity and decreased parasympathetic activity, is postulated to be implicated in SCZ and its treatment. The aim of this narrative review is to view SCZ through an autonomic lens and synthesize the evidence relating autonomic dysfunction to different domains of SCZ. Using various methods of assessing autonomic activity, autonomic dysfunction was found to be associated with multiple aspects of SCZ pathophysiology, including symptom severity, cognitive impairment, and the development of cardiometabolic comorbidities, such as metabolic syndrome and high BMI. The strongest association of low heart rate variability was noted among patients on antipsychotic treatment with high-affinity muscarinic antagonism (i.e., clozapine, olanzapine and quetiapine). The review will also suggest ways in which studying autonomic dysfunction can help reduce morbidity and mortality associated with SCZ and its treatment.

Salivary secretion and salivary stress hormone level changes induced by tongue rotation exercise

PURPOSE

Prevention of xerostomia and stress is important to prolong healthy life expectancy and improve the quality of life. We aimed to investigate the effects of tongue rotation exercise for increasing salivary secretions and stabilizing salivary stress hormone levels.

MATERIALS AND METHODS

Twenty four participants without subjective oral dryness were enrolled. The exercises comprised tongue rotation exercise and empty chewing. The salivary stress hormone level was measured using a Salivary Amylase Monitor. Unstimulated whole saliva volume and salivary amylase activity were measured before tongue rotation exercise or empty chewing and subsequently 5, 10, and 15 minutes after these exercises. Differences in the rates of change of unstimulated whole saliva volume and salivary amylase activity were analyzed by repeated measure analysis of variance.

RESULTS

Statistically significant differences among the rates of change were not observed after empty chewing for unstimulated whole saliva volume and salivary amylase activity at the four measurement times. However, the rate of change of unstimulated whole saliva volume and salivary amylase activity were statistically significantly different among the four time points: before the tongue rotation exercise and 5, 10, and 15 minutes post-exercise (P< .05 and P<.01, respectively).

CONCLUSION

Tongue rotation is effective in increasing saliva secretion, reducing stress, improving oral function, and extending healthy life expectancy.

Salivary Alpha-Amylase Activity Levels in Catatonic Schizophrenia Decrease after Electroconvulsive Therapy

Background. Dysfunction of the autonomic nervous system (ANS) in schizophrenia has been detected by electrophysiological methods, but the underlying mechanisms remain unknown. Several studies have suggested that measuring salivary alpha-amylase activity levels is useful for evaluating the ANS activity and that sAA levels increase in schizophrenia and correlate with Brief Psychiatric Rating Scale (BPRS) scores. However, no study has examined the relationship between sAA activity levels and symptoms of schizophrenia with catatonic state. Methods. We present the case of a 59-year-old female with persistent catatonic schizophrenia treated by electroconvulsive therapy. We evaluated the ANS activity by measuring sAA activity levels before and after ECT, and we evaluated her symptoms using the BPRS and Bush–Francis Catatonia Rating Scale (BFCRS). Results. ECT was highly effective and BPRS and BFCRS scores substantially decreased. sAA activity levels decreased from 125 kU/l to 33 kU/l. Conclusions. sAA activity levels could be a potential biomarker of schizophrenia with catatonic state.

Salivary stress biomarkers and anxiety symptoms in children with and without temporomandibular disorders

The etiology of temporomandibular disorders (TMD), which are considered as a heterogeneous group of psychophysiological disturbances, remains a controversial issue in clinical dentistry. This study aimed to evaluate whether the salivary alpha-amylase (sAA), cortisol levels, and anxiety symptoms differ between children with and without TMD. Initially, 316 young subjects were screened in public schools (nonreferred sample); 76 subjects aged 7-14 years were selected and comprised the TMD and control groups with 38 subjects each matched by sex, age, and the presence/absence of sleep bruxism. Four saliva samples were collected: upon waking, 30 min and 1 h after awakening (fasting), and at night (at 8 PM) on 2 alternate days to examine the diurnal profiles of cortisol and sAA. Anxiety symptoms were screened using the Multidimensional Anxiety Scale for Children (MASC-Brazilian version). Shapiro-Wilk test, Student's t-test/Mann-Whitney U test, and correlation tests were used for data analysis. No significant differences were observed in the salivary cortisol area under the curve (AUCG mean ± SD = 90.22 ± 63.36 × 94.21 ± 63.13 µg/dL/min) and sAA AUCG (mean ± SD = 2544.52 ± 2142.00 × 2054.03 ± 1046.89 U/mL/min) between the TMD and control groups, respectively (p > 0.05); however, the clinical groups differed in social anxiety domain (t = 3.759; CI = 2.609, 8.496), separation/panic (t = 2.243; CI = 0.309, 5.217), physical symptoms (U = 433.500), and MASC total score (t = -3.527; CI = -23.062, -6.412), with a power of the test >80% and large effect size (d = 0.80), with no significant correlation between the MASC total score, cortisol, and sAA levels. Although children with TMD scored higher in anxiety symptoms, no difference was observed in the salivary stress biomarkers between children with and without TMD.

Investigation of the Endogenous Stress Response System in Patients with Chronic Schizophrenia

OBJECTIVE

Cardiophysiological and neuroendocrine studies suggest that the two components of the endogenous stress response system, the sympathetic nervous system (SNS) and the hypothalamic-pituitary-adrenal (HPA) axis, are dysregulated in patients with schizophrenia. However, cardiophysiological measures are influenced by several confounding factors and the secretion of α-amylase in saliva is believed to represent a more reliable index of SNS activity. Therefore, to characterize the functional status of the SNS and HPA axis in schizophrenia we explored the concomitant salivary secretion of cortisol and α-amylase.

METHODS

Saliva cortisol and α-amylase levels were measured after awakening in 30 patients with chronic schizophrenia and 22 healthy subjects.

RESULTS

After awakening, saliva cortisol increased in a similar way in both patients and healthy controls, while saliva α-amylase concentrations showed a clear-cut decrease in healthy subjects but not in patients with schizophrenia. No significant correlation emerged between biochemical measures and patients' demographic or psychopathological characteristics.

CONCLUSIONS

These findings demonstrate normal activity of the HPA axis with an enhanced SNS tone, which suggests a functional dissociation of the two components of the endogenous stress response system in patients with chronic schizophrenia. The pathophysiological significance of such dysregulation needs further studies to be clarified.

A small randomized pilot study of a workplace mindfulness-based intervention for surgical intensive care unit personnel: effects on salivary α-amylase levels

OBJECTIVE

To determine whether a workplace stress-reduction intervention decreases reactivity to stress among personnel exposed to a highly stressful occupational environment.

METHODS

Personnel from a surgical intensive care unit were randomized to a stress-reduction intervention or a waitlist control group. The 8-week group mindfulness-based intervention included mindfulness, gentle yoga, and music. Psychological and biological markers of stress were measured 1 week before and 1 week after the intervention.

RESULTS

Levels of salivary α-amylase, an index of sympathetic activation, were significantly decreased between the first and second assessments in the intervention group with no changes in the control group. There was a positive correlation between salivary α-amylase levels and burnout scores.

CONCLUSIONS

These data suggest that this type of intervention could decrease not only reactivity to stress but also the risk of burnout.

Evaluation of autonomic nervous system by salivary alpha-amylase level and heart rate variability in patients with schizophrenia

Several researches indicate that autonomic nervous system (ANS) dysfunction in patients with schizophrenia. Recently, salivary alpha-amylase (sAA) has been employed as a useful marker for ANS function. We investigated the extent of ANS dysfunction by measuring sAA and heart rate variability (HRV) of 25 patients with schizophrenia compared with controls. Schizophrenia group demonstrated a significant increase in sAA and markedly lower parasympathetic nervous system (PNS) activity in the HRV. However, there were no significant differences between two groups in sympathetic nervous system (SNS) activity. We concluded that PNS might be suppressed and the SNS shows relatively high activity in schizophrenia.

Effects of a single bout of walking on psychophysiologic responses and executive function in elderly adults: a pilot study

Background

The purpose of this study was to examine the effects of a single bout of walking on mood, psychophysiologic responses, and executive function in elderly adults.

Methods

Twenty healthy, elderly adults (10 women and 10 men; mean age 70.50 ± 3.4 years) participated in this study. Mood, as assessed by the Profile of Mood States, and salivary α-amylase activity were examined before and after walking. Executive functions were also evaluated by the Wisconsin Card Sorting Test.

Results

Negative feeling scores such as tension-anxiety, anger-hostility, and confusion significantly improved after walking. No significant differences were found for either salivary α-amylase activities or Wisconsin Card Sorting Test scores before and after walking. However, the changes in salivary α-amylase activity before and after walking correlated positively with the number of total errors and perseverative errors of Nelson in the Wisconsin Card Sorting Test.

Conclusion

These results suggest that moderate exercise, such as self-paced one-time walking, induces beneficial psychologic effects in elderly adults. Meanwhile, the significant increase in salivary α-amylase activity after walking might temporarily cause deterioration of executive function.

Is salivary alpha-amylase an indicator of autonomic nervous system dysregulations in mental disorders?--a review of preliminary findings and the interactions with cortisol

During recent years, a growing interest emerged in using salivary alpha-amylase (sAA) as a non-invasive, surrogate marker for sympathetic activity. Numerous studies applying stress protocols have demonstrated that sAA is highly sensitive to stress-related changes (in healthy subjects). Additionally, it was suggested that sAA might moreover serve as an index for pathological dysregulation of the autonomic nervous system (ANS) in patients showing psychopathology. Since then, a small but growing literature investigated sAA in patients with mental disorders. This review aims to give an overview of preliminary findings in this field of research. The results of n=15 studies are described in detail and implications for further research are discussed. Although the number of studies and the samples examined were rather small, changes in sAA, reflecting adrenergic dysregulation, could be demonstrated in psychopathology, especially in anxiety-related disorders. This field of research is still in its early stages. However, the studies included in this review revealed first evidence that the employment of sAA, as an indicator of ANS dysregulation in mental disorders, is promising.

May salivary alpha-amylase level be a useful tool for assessment of the severity of schizophrenia and evaluation of therapy? A case report

Background. Previous studies suggested dysfunction of the autonomic nervous system (ANS) in schizophrenia patients, but the mechanism remains unclear. Recently, the measurement of salivary alpha-amylase (sAA) has been considered a useful tool for evaluating ANS, especially the sympathoadrenal medullary system. Furthermore, there was a report that patients with schizophrenia showed much higher sAA level than normal controls. Methods. We present the case of a 51-year-old female with catatonic schizophrenia. She needed the treatment of electroconvulsive therapy (ECT). We evaluated her sAA level and her psychiatric symptoms during the treatment. Results. Before ECT treatment, she showed high sAA level. Her sAA level decreased during the course of ECT, and this attenuation was accompanied by improvement of schizophrenic symptoms. Conclusion. We consider that measurement of the sAA level may be one of the useful biological markers for assessment of psychotic state and efficacy of treatment in patients with schizophrenia.