Stress and Headache

Below is an explanation for the connection between stress, pain and migraine.

We all have experienced stress, but we need to know what exactly is it and how it is scientifically measured. Stress can be thought of as a stimulus that causes a strain. An analogy might be a weight pulling down on a spring; the more weight (Kg) the more the spring is extended (Cm). We can derive a law that relates to weight and the extension on a spring such in Hooke’s law. We can also think of stress as a response. In the spring analogy, the stress measure would be the extension. You may be glad to hear that humans are considered more complex and adaptable than springs. Psychologists think of stress in terms of a dynamic transaction between stimulus and a response, where the individual can modify the process by coping. The person is not just a passive responder but is active and reactive to the stress process.

The stress response in humans consists of physiological changes such as heart rate, muscle tension, pupillary changes and stress hormones released like adrenaline and corticosteroids. Up to a point, our bodies try to adapt, but beyond this, fatigue and exhaustion set in. The problem with physiological measures is that similar physiological changes can occur during strong pleasant experiences as well as negative unpleasant experiences. Changing home, promotion and marriage are major positive life events, which are stressful. The bottom line is, what the individual is feeling like?

What really matters is what we feel. We may be so profoundly tired and yet paradoxically unable to sleep. We may worry about what is going on around us and we become anxious. We may feel fed up and irritated with our lot and get angry with our loved ones, friends and colleagues. We may be less helpful, less clear thinking, and start to feel sorry for ourselves. When we feel stress, the human experience has a full repertoire of mood to play upon. The Short Pain Inventory (SPI©) was developed to measure the intimacy between physical pain and emotion. The correlation of physical pain ratings and mood disturbance is typically around 0.7 revealing that (0.7x0.7) 50% of the variation in physical pain is related to mood. Properly developed valid psychological test instruments can have superior validity, discriminability and reliability than some common physiological measures. The days of using a 10cm lines (visual analogue) to measure pain should be mostly historical. Over the past 100 years, psychometrics has advanced considerably, particularly aided by modern-day powerful computing.

The main feature of migraine and headache is of course pain. In a series of studies, we developed a specific psychological test that narrowed down about 300 questions to 17 items that were highly discriminating between subjects with and without pain. Moreover, we developed the SPI© test to discriminate between fine gradations of pain including mild, moderate severe and extreme pain. We carried out laboratory studies to induce tiredness with Benzodiazepines and calibrated the test against computerised psychometric tests. We carried out analgesic clinical trials and used the test to measure the efficacy of the test in randomized placebo controlled studies. We then looked at pain in various situations including elective surgery, dental patients and mixed groups in the pain clinic. We compared the reliability and discriminability with other well established tests such as the McGill Pain Questionnaire (MPQ), The Headache Impact Test (HIT-Dyna®) and the Spielberger State-Trait Anxiety Inventory. Recently we have used the SPI test in primary care to examine the pain of headache patients divided into tension type headache (TTH), chronic daily headache (CDH) and migraineurs.

Pain and mood disturbance are causally related. The more pain a patient experiences, the worse their concomitant mood disturbance. Migraineurs and other types of headache are no exception to the rule. Moreover, the painful experience of a migraine changes our mood profoundly. We have also found that schoolteachers have ten times the incidence of physical pain than other groups of white-collar workers. We have measured teachers’ stress and they have mood disturbance even without pain and this lowers the threshold by which pain eventually breaks through into consciousness. Mood disturbance is core feature of stress and stress can amplify the pain experience and modify it. We ourselves can modify our mood, which gives us a window of opportunity for treatment and prophylaxis. Pharmacologists are not clear as to how antidepressants work on pain. One mechanism is by direct neurochemical 5HT action and the other is possibly by altering the mood. Cognitive behavioural therapy (CBT) has proven efficacy in ameliorating anxiety and sadness and such mood elevating treatments lend themselves well in the treatment tools of pain and headache. CBT is now a common treatment offered in the pain clinic. Massage, relaxation, reflexology probably work via mood-induced changes. Any religious or spiritual assistance may also be mediated by ameliorating stress related moods. The important point is that we have the tools to measure this.

Source: Dr Shaun Kilminster

Publication Date: February 2004


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