Saliva testing Uses in behavioral research

Saliva testing also has specific uses in clinical and experimental psychological settings.Because of its insight into human behavior, emotions, and development it has been used to study psychological phenomena such as anxiety, depression, PTSD, and other behavioral disorders.Its main purpose is to test cortisol and alpha amylase levels, which indicate stress levels.Salivary cortisol is a good indicator of stress, and increases in cortisol levels correlate positively with increases in stress levels.Cortisol levels rose slowly over time and took a while to return to basal levels, suggesting that cortisol is more related to chronic stress levels.On the other hand, α-amylase rises rapidly when a stressor is encountered and quickly returns to baseline after the stress has passed,making salivary amylase measurements a powerful tool in psychological research investigating acute stress responses.Samples are typically collected from participants by having them drain saliva through a straw into a collection tube as they experience the stimulus, with samples taken every few minutes to record gradual changes in stress hormone levels.Because the collection of saliva samples is non-invasive, it has the advantage of not putting further stress on the participants that might skew the results.

In more specific studies examining the link between cortisol levels and psychological phenomena, chronic stressors such as life-threatening situations (eg: illness), depression, and social or economic difficulties have been found to be significantly associated with cortisol levels.In subjects experiencing anxiety-inducing conditions, high cortisol levels corresponded to experiencing more stressful physiological symptoms, such as increased heart rate, sweating, and increased skin conductance.Furthermore, an inverse correlation was found between baseline cortisol levels and aggression.Thus, salivary cortisol levels can provide insight into many other mental processes.

Alpha-amylase levels in saliva provide a non-invasive way to examine sympathetic adrenal medulla (SAM) activity, which can otherwise be measured using electrophysiological equipment or plasma readings.Salivary alpha-amylase levels have been found to correlate with elevated levels of autonomic nervous system activity, responding in a similar manner to the hormone norepinephrine.Subsequent discoveries revealed the relationship between α-amylase and competition.The results showed that alpha-amylase levels changed in response to competition, but not in anticipation of competition. In addition, by testing alpha-amylase levels, the scientists noticed differences in response behavior between individuals with prior experience in similar situations.While saliva testing promises to be a valuable and more widely used tool in future psychological research, some disadvantages of the method must also be kept in mind, including the cost of collecting and processing samples and the reliability of the analysis. the measure itself.The substantial variability in cortisol levels within and between people must be taken into account when drawing conclusions from research.

A number of studies have been conducted to further examine the variables responsible for these within-person and between-person differences. Analysis of variables affecting cortisol levels yielded a large number of confounding variables.Diurnal variation is a major factor in variation within individuals, as baseline cortisol levels are known to vary depending on the time of day.In normally developing individuals following a typical circadian schedule, cortisol production peaks during the last hours of sleep.This peak is thought to help prepare the body for action and stimulate appetite upon waking.Diurnal variation is also affected by psychological conditions. For example, early morning cortisol levels have been found to be elevated in shy children and late night cortisol levels in depressed adolescents, especially between two and four in the afternoon.This may be important for understanding mood and depressive symptoms.Other variables affecting intrapersonal and interpersonal differences.This list is not comprehensive and the effects of many of these variables may benefit from further research and discussion.

• Age is one of the main factors that vary from person to person.Several studies have shown that children and adolescents display greater cortisol activity, which may be related to development.Gender has been found to affect baseline cortisol levels, resulting in differences between individuals.During generally stressful situations,men's cortisol levels were found to nearly double compared to women's.However, women but not men tend to exhibit significantly higher cortisol levels in stressful social situations (i.e., social exclusion challenges).

• The menstrual cycle has been found to affect the levels of cortisol in the body, which can vary within and between people. Cortisol levels have been reported to be the same in women during the luteal phase as in men,suggesting that there is no sex difference in basal levels of cortisol when women are not ovulating.Significantly lower cortisol levels have been reported in women in the follicular phase and in women taking oral contraceptives compared with men and women in the luteal phase.

• Pregnancy has been found to increase cortisol levels in the body.In particular, breastfeeding reduces cortisol levels in the short term, even when the mother is under psychosocial stress.

• Nicotine is known to increase cortisol levels in the body because it stimulates the HPA axis. After smoking at least two cigarettes, smokers had significantly higher salivary cortisol levels. In addition, habitual smokers have a blunted response to salivary cortisol from psychological stressors.

• Food has been found to affect cortisol levels.The presence of the protein has been found to increase cortisol.This variable is often influenced by diurnal variation, with cortisol being significantly higher at lunchtime than dinnertime, and sex, with women having higher levels of cortisol after eating than men.

• While some studies examining the effects of alcohol consumption and caffeine intake on basal levels of cortisol have found positive associations, the results are mixed and further research is needed.Vigorous or prolonged exercise can increase cortisol levels. Short-term and low-level exercise only modestly increases cortisol levels.Repeated exposure to an initial stressful stimulus has been found to cause a decrease in cortisol levels in the body.Birth weight has been shown to be inversely related to basal cortisol levels.Low birth weight is associated with high levels of cortisol. 

• Position in the social hierarchy has been found to affect cortisol levels.One study specifically looked at a sample of 63 military recruits and found that socially dominant subjects showed high salivary cortisol increases, whereas subordinate men showed only modest increases after stress exposure and physical exercise.Certain medications (ie, corticosteroids, psychotropic drugs,antidepressants) have been found to affect cortisol levels in the body but studies examining these effects have had mixed results.