Lecture2: Anxiety

The last psychological issue regarding fear and anxiety is to distinguish between the state and trait aspects. As I mentioned earlier, when patients show their anxiety, we need to clarify if that relates more to their personal trait or if that relates more to the state or both. For example, patients may tend to feel anxious about everything, which is not specific to the dental setting. On the other hand, even a very ‘calm’ person may feel strong anxiety when the situation is very anxiety-provoking. To clarify the state and trait aspects is very important for making a good decision about managing patients’ negative emotions. And this is critical to assess patients’ fear and anxiety.

As we will see in our later course, the use of dental anxiety scales or questionnaires helps us to quantify the degree of patients’ fear and anxiety in the dental setting. In fact, there is one type of trait anxiety that dental professionals should take care of. That is dental anxiety. Dental anxiety can be considered as anxiety toward many aspects of dental care service. Therefore, it is highlighted as ‘dental care-related fear’ by some researchers. However, dental anxiety should be distinguished from state anxiety, which focuses on the anxiety and fear specific to a specific moment during dental treatment. For example, patients may have higher state anxiety right before treatment and feel relieved after the treatment.

State anxiety may fluctuate between different state of dental treatment. For example, patients may feel increased fear toward needle injection but feel relieved for the following dental scaling. Dental anxiety, in contrast, is considered a personal trait. Patients with higher dental anxiety are more tended to feel anxious about dental care as a whole, even the treatment procedure is considered ‘mild’. Therefore, it would clinically important to assess dental anxiety individually for each patient. The assessment can be done easily with the scales of dental anxiety, which have been studied extensively in the literature. Before concluding this section, I need to mention a little bit about the brain mechanisms of fear and anxiety, which is one of the major fields in affective neuroscience.

Research evidence suggests that there is no such thing as a ‘fear centre’ in the brain. The amygdala, for example, plays a key role in fear conditioning, i.e., the formation of the association about what is fearful. However, the experience of fear is shaped by the participation of many brain regions, including the modulation from the higher cortex. For example, the dual-route model by Joseph LeDoux suggests that an aversive stimulus, such as a loud noise may trigger an escape behaviour via the amygdala. However, we seldom run immediately after being scared – because the cortex, including the prefrontal cortex, will integrate more information from the context, which may tell us that we are safe.

The modulation from the cortex would work with the amygdala so that we can make a proper response. The prefrontal cortex also plays a key role in the cognitive process of emotional stimuli. For example, different emotional experiences may occur when we pay to shift our attention between the stimuli or when we ‘think twice,’ revisiting the same stimuli from a different frame. This is also the biological basis of cognitive-behavioural management of fear and anxiety, which we will learn in our later course. Before closing this part, I need to clarify that the ‘mechanisms’ or the line drawing here should not be interpreted as a fixed pattern of cable lines or the circuitry in a microchip.

They are not ‘fixed’ or ‘unified’ by a standardized industry process. In the contrast, the figures here represent the flexibility of information processing of the brain. It highlights the fact that when the brain works on a stimulus it keeps on integrating information. What is more important is the variation of information processing between different individuals. For example, some people may have a stronger connection between two brain regions, which may reflect an increasing or decreasing amount of information processing, compared to other people. Simply speaking, the variety of our emotional experiences is highly associated with individual differences in the brain mechanisms of information processing.