Pain is typically defined by neuroscientists as an unpleasant sensory and emotional experience associated with actual or potential tissue damage (Sufka & Lynch, 2000).  Pain is highly associated psychologically with distress as an undifferentiated protest against anything that is unpleasant or aversive (Kalat & Shiota, 2007).  The function of pain is generally believed  to be the escape and avoidance to prevent further trauma and/or promote the healing processes (Williams, 2002).  Pain is experienced by everyone, but is expressed in different ways (Llewellyn, n.d.).  These definitions suggest pain is an emotional experience.  I will show how pain fits into all five criteria of a basic emotion, then I will compare pain to the emotions already classified as basic in the way they are related to mental illness in order to provide further evidence that pain is in fact a basic emotion.

Comparing pain with the current criteria             

The first criterion as a basic emotion is universal within the human species.  While cultural differences exist in perceptions and communication of pain, there is no question that pain does exist in every culture (Llywellyn, n.d.).  If certain cultures did not experience pain, given this information, we would see cultures that do not experience pain dying off.  Culture is recognized as being a strong indicator of how one perceives and reacts to pain (Llewellyn, n.d.).  However, even with these differences in mind, they act to establish the fact that pain exists in every culture to the extent that pain is distinguishable.  Given thought to the variances in pain perception, studies still show that there are built-in avenues for people to express pain as a way of eliciting medical attention from a caregiver.  Pain can be broken down into two types of expression.  The first is stoic which is very internalized, and the second emotive which manifests itself in a more verbalized manner (Llewellyn, n.d.).  Regardless of culture, these two types of expressions may occur.  Since one person from an Asian culture may be stoic this does not mean people of any other culture do not experience pain in this way.  While pain expression can be based in culture, it is also a very personal experience.  Since all cultures are ultimately composed of individuals, these differences exist in any and every culture.           

The next criterion involves facilitating a functional response to specific, prototypical life event, or antecedent.  As previously mentioned we know pain is a functional response, and is critical to human survival.  Pain acts as a notification to the person experiencing the pain to alert them to danger or injury.  Pain forces the person feeling the pain to stop doing what has caused the pain, and allow the body to heal.  Basically, pain motivates one into changing a specific action in order to ensure survival (Williams, 2002).             

The next category to approach is the criterion involving emotion being evident early in life.  Hummel, Puchalski, Creech, and Weiss, (2003) show this with their diagram of facial expressions in neonates (see Figure 1). 

Figure 1. Facial Expression of Physical Distress and Pain in the Infant     

Figure 1 shows distinct facial qualities in babies' expression of distress and pain.  The identification of pain in infants has been a primary factor preventing pain from being classified as a basic emotion.  We know babies express pain, because they have only two ways of expressing these feelings which are through facial expressions and verbal expressions.  In the N-Pass scoring criteria for Neonatal pain, agitation, and sedation scale (Hummel et al., 2003) the numbers assigned to each area of  facial expression, physical expression, physiological expression, verbal expression, and behavioral expression are associated with the each other as a way to gauge over-all pain and agitation.  This shows the interaction with these types of expression and the reality that they all play a part in the expression of pain, and how these expressions are evident early in life in their purest form.             

Another criterion pain fits into is having built-in way of expressing, such as facial expression or tone of voice.  As was just discussed, pain is expressed clearly through facial expression, verbalization, tone of voice/crying, and body posturing.  This is done as to elicit help from others to express pain level and locale (Williams, 2002).  When communicating with caregivers, these expressions are vital in obtaining the appropriate type of care available.  As shown in Figure 2  facial expressions of pain continue throughout life (Sufka & Lynch, 2000), but can be altered depending on cultural context (Llewellyn, n.d.).  The anatomical features of pain in facial expression are comparable to those of the neonatal expression of pain in Figure 1 with the eyes tightly closed, brows lowered and drawn together, and the nose broadened and bulging.


Figure 2. Facial Expressions of Pain in Adults 

Finally, pain meets the last criteria that each primary emotion should have its own physiological basis.  Neuroscientists agree that pain consists of two components, one is sensory and the other emotional.  The sensory component is also referred to as nociception and involves the processing of the location, quality, and intensity of pain.  The emotional component is part of the hurtful and unpleasant sensations that come with the actual physical damage (Sufka & Lynch, 2000).             

The neurophysiology involves a complex transmission of signals that start in the nociceptors where thermal and chemical stimuli are detected.  Following this introduction a transaction of this information occurs with the central nervous system.  This process occurs in the spinal cord where a synapse occurs with nociceptive specific, wide dynamic range second-order neurons.  These second-order neurons project to supraspinal centers, mainly the thalamus.  The hypothalamus, amygdala, periaqueductal and reticular formation is also projected upon.  Projection neurons then from these centers extend their axions to specific areas of the cortex, which includes the primary somatosensory, anterior cingulate, insular, and medial prefrontal areas.  The neurotransmitters involved in this process are substance P, glutamate, neurokinin A, and calcitonin-gene-related peptide.  The cortex is also involved in the cognitive aspects of pain reception.  Figure 3 is a map of the neurophysiology of pain.  The lateral pain system regulates the quantitative coding for the type of stimulus involving the location of pain and intensity of pain felt.  The medial pain system codes the affective or motivational components involved in the processing of pain in the limbic regions of the frontal lobe (Sufka & Lynch, 2000).

Figure 3. Schematic Diagram of the Medial and Lateral Pain System (Sufka & Lynch, 2000) 

Further comparison           

Now that the basic criteria for qualifying an emotion as a basic emotion have been established, more evidence will be presented to associate pain with the other basic emotions in their causations of mental illness.  This evidence involves mental illness and how the six basic emotions are related to these illnesses.  In this comparison, the relationship of pain as is made of the other basic emotions, will demonstrate this similarity.  When speaking of all the basic emotions, the involvement they have with the mental illnesses they are associated with is done when the emotion is excessive; just as with pain and its relativity to mental illness.           

Sadness in excess is relative to major depressive disorder.  Excessive happiness in combination with excessive sadness is a cue of bi-polar disorder.  Excessive anger can be correlated with many illnesses such as attachment disorders, PTSD, and many others.  Disgust in excess can be a symptom of eating disorders and OCD.  Fear is a symptom of various phobias, schizophrenia, and PTSD.  While surprise in excess can be a sign of PTSD.  The illnesses used as examples do not comprise a full listing of all illness, and can be seen in the DSM-IV. 

Pain is also a catalyst for several types of mental illness when experienced in excess.  Chronic pain, specifically Reflex Sympathetic Dystrophy (RSD), has been shown to initiate anger, depression, anxiety, enhanced disability behavior (which can be directly associated with physical injury and its effects), and hostility (Turner-Stokes, 2002).  Reflex sympathetic Dystrophy occurs after surgery or physical trauma.  Essentially the mind thinks the body is still injured, and reacts physiologically with sending pain signals to the brain from the site of injury, and the brain responds by manifesting the appropriate responses for the type of injury it thinks still exists.  Some of the symptoms created at the location are pain, swelling, skin discoloration and sensitivity, and others that are specific to the patient (Turner-Stokes, 2002).  RSD is a great example for examining excessive pain since it emulates the properties of pain as it occurs initially.  RSD creates a physical environment vasomotor and autonomic properties of swelling, skin discoloration, and temperature changes (Turner-Stokes, 2002).           

The link between the effects of the already classified basic emotions and pain is an association that has not been looked at as an additional factor of consideration when classifying pain as a basic emotion.  However, this aspect is very important because when pain is finally recognized as a basic emotion this reality can be better researched.  When pain is approached with these factors in mind, treatment of patients suffering from the physical and psychological ramifications of excessive pain will be tended to, and a more efficient patient care plan can be enacted. 

Conclusion           

After being presented with a comparison of pain with the criteria that determine an emotion as basic, you can see that it indeed fits the bill.  Pain fits into all the criteria, and does so without question.  In examining the importance of classifying pain as a basic emotion you can see why pain needs this classification.             

Research by Bruehl and Chung (2006) shows a significant improvement of RSD symptoms by use of Behavioral-Cognitive therapy.  Bruehl and Chung (2006) show that psychological disturbances can exacerbate physical symptoms of pain with RSD patients.  These are great findings as they approach the physical symptoms with psychological aspects of this pain disorder.  Ciccone, Bandilla and Wu (1997) support the evidence provided by Bruehl and Chung (2006) by affirming the use of cognitive behavioral therapy as an effective method in treating chronic pain.  In addition, Ciccone et al., (1997) show ways RSD is similar to the effects of neuropathy.  One primary similarity with the two disorders is the overwhelming frustration when dealing with a seemingly intangible physical symptom.  The research showed that this frustration was highly associated with the psychological impacts of chronic pain.           

Feldman, Downey & Schaffer-Neitz (1999) further delve into the minds of those afflicted with chronic pain.  An important finding of their research is the incredible correlation between depressed mood and sensation of pain.  This was a positive correlation, so both pain sensation and mood effected each other.  Feldman et al., (1999) supports previous evidence that anxiety and depression are dysfunctions associated with chronic pain.  They also found that  perceived social support had a great impact on the likelihood that someone who experiences injury or surgery will acquire some sort of chronic pain disorder.           

Mailis (1996) looks at the tolerance of frustration in chronic pain patients and how it appears to be exacerbated compared to those not afflicted with chronic pain.  Mailis (1996) addresses  need for autonomy in patient care when faced with an intangible pain disorder.           

Meredith, Strong and Feeney (2006) confirm other research that broaches the concept of social support and its benefits for those who suffer from chronic pain.  These researchers  approach attachment style as another factor leading to chronic pain.  They state those with poor coping skills and attachment styles are at greater risk of suffering from chronic pain, and this may show a strong association of these types of people being effected with chronic pain.  Meredith et al., (2006) show a correlation of anxiety producing poor coping skills and perception of pain.  Those with greater anxiety experience a lower threshold for pain.  Further, Turner-Stokes (2002) provide evidence that those who are already prone to depression, anxiety, have a greater need for social support are at greater risk of acquiring RSD after a physical trauma.  Turner-Stokes (2002) reiterates the importance of psychological treatment and learned coping skills in improving the patient's perception of their situation. 

As was shown in this paper, those afflicted with chronic pain deal with a myriad of emotional and psychological consequences on top of the physical anguish everyday.  When all aspects of pain are considered in treatments, a holistic approach is more likely and will produce better results for the patient.  This is especially so when caregivers can be made aware of the emotional impact their chronic pain patients face.  This is highly important as there is currently little attention paid to the psychological aspects of chronic pain.  When pain is classified as a basic emotion more attention will be paid to exploring the emotional facets of this affliction.  More research is necessary to help define a solid methodology to approach chronic pain, and in doing so people who suffer from this will be able to, some day, possibly avoid chronic pain all together.  If anyone who suffers from this debilitating condition can be better assisted as to prevent the catastrophic results that come from the physical torment and mental illnesses that accompany chronic pain, the purpose of examining the classification of pain as a basic emotion will be well served.

Bruehl, S., & Chung, O.Y. (2006). Psychological and Behavioral Aspects of Complex Regional    Pain Syndrome Management. Clinical Journal of Pain, 22, 430-437.

Ciccone, D.S., Bandilla, E.B., & Wu, W. (1997). Psychological dysfunction in patients with  reflex sympathetic dystrophy.  Pain, 71, 323-333.

Feldman, S.I., Downey, G., & Schaffer-Neitz, R. (1999). Pain, negative mood, and perceived support in chronic pain patients: A daily diary study of people with reflex sympathetic dystrophy syndrome. Journal of Consulting and Clinical Psychology, 67, 776-785.

Hummel, P.A., Puchalski, M.L., Creech, S.D., & Weiss, M.G. (2003). Neonatal pain, agitation, and sedation scale. N-Pass. Retrieved October 28, 2006, from http://www.n-pass.com/scoring_criteria.html

Kalat, J.W., & Shiota, M.N. (2007). Emotion. Belmont, CA: Thompson Wadsworth.

Llewellyn, A. (n.d.). Cultural diversity and pain management. PRIME. Retrieved November 7, 2006, from http://www.cahq.org/docs/2003/CulturalDiversityPainManagement.pdf#search='cultures%20that%20do%20not%20recognize%20pain

Mailis, A. (1996). Compulsive targeted self-injurious behaviour in humans with neuropathic pain: A counterpart of animal autonomy? Four case reports and literature review.  Pain, 64, 569-578.

Meredith, P.J., Strong, J., & Feeney, J.A. (2006). The relationship of adult attachment to emotion, catastrophizing, control, threshold and tolerance, in experimentally-induced pain. Pain, 120, 44-52.

Sufka, K.J., & Lynch, M.P. (2000). Sensations and pain processes. Philosophical Psychology, 13, 299-311.

Turner-Stokes, L. (2002). Reflex sympathetic dystrophy: A complex regional pain syndrome. Disability and Rehabilitation: An International Multidisciplinary Journal, 24, 939- 947.

Williams, A.C. (2002). Facial expression of pain: An evolutionary account. Behavioral and Brain Sciences, 25, 439-455.