Psycho-neuro-immunology

8 January 2002

Pubished in The Age

For thousands of years the world’s healing systems - tribal, classical and medieval - held that mind and emotions were intertwined with physical health. Indeed these healing systems are often described as “holistic” because they don’t separate the body from the mind at all.

Now a new science known as psycho-neuro-immunology (PNI) is discovering how far this idea can be taken. PNI researchers are discovering the bodily pathways that are used to convey messages from the outside world, through our psyches, to our nervous, endocrine and immune systems - and on to influence health or illness.

Dr Kavita Vedhara is a British health psychologist working in the field of PNI. “In the last 20 to 30 years,” she says, “PNI has provided convincing evidence that psychological states have physiological repercussions. Increased psychological morbidity [imbalance or unwellness] alone has been shown to affect blood pressure, hormones such as cortisol, and a range of immune parameters.

“Distress in the elderly is associated with impaired immunity to disease. Distress can impair the healing of wounds. And cognitive-behavioural interventions - in particular the recent work on emotional disclosure - can enhance immunity.”

“Emotional disclosure” is the process of writing or talking about a traumatic or stressful event - “letting things out”.

“There is an emerging literature on this,” says Dr Vedhara, “which has shown that even after four sessions of such disclosure, participants display a range of beneficial changes in health behaviours and immunity.”

The “father” of psycho-neuro-immunology is Professor Robert Ader of the University of Rochester in New York State. In the same way that Pavlov had conditioned his dogs to salivate upon the ringing of a bell, in the 1970s Ader  psychologically conditioned rats to suppress their immune systems, simply by drinking a sweet drink.

In 1975 Ader and a colleague, Dr Nicholas Cohen, published their findings in the journal Psychosomatic Medicine. Ader came up with the name psycho-neuro-immunology, and a new science was born.

Professor Ader told The Age he believes we still lack clear-cut evidence that "psychosocial" factors influence human disease through the immune system. But: "The hypothesis that psychosocial factors could influence some disease processes via changes in immune function is a perfectly legitimate one that follows from what is already known about the neuroendocrine changes that accompany emotional states, for example. Recent studies in animals are yielding data that support this hypothetical chain of events."

In the years since Ader's original discovery, it has been established that the nervous, immune and endocrine systems communicate via networks of peptide molecules. Mechanisms linking stress with increased susceptibility to infection, cancer and heart disease have been better understood.

Perhaps the most famous researcher in this area is Dr Candace Pert, former director of Brain Biochemistry at the US National Institutes of Health. As a graduate student in the 1970s Dr Pert made her name - and medical history - by discovering the brain’s opiate receptors. Her landmark discovery paved the way for the “information-based” model of the body’s internal communication systems which is now replacing the “structuralist” model.

In a 1995 interview, Dr Pert opined that the hippocampus area of the brain - which contains every variety of peptide - is the “gateway” to emotional experience. Emotional memories, she said, are accessed through the peptide network. But the peptide network does not end in the brain: peptides are also found in the body’s organs, tissues, muscles, skin and glands.

“They all have peptides receptors on them, and can access and store emotional information. This means this emotional memory is stored in many places in the body, not just the brain.

“For example, if you have a memory that has to do with food and eating, you might access it by the nerves hooked up to the pancreas.

“I believe that unexpressed emotion is in process of travelling up the neural access. By travelling, I mean coming from the periphery, up the spinal cord, up into the brain. When emotion moves up, it can be expressed.”

Dr Pert’s research has important implications for the future of the various psycho-therapies:

“There are inhibitory chemicals and impulses that function to keep the emotion and information down.

“Unexpressed emotions are buried in the body - way, deep down in the circuitry of the organs, or the gastro-intestinal tract, or a loop in a ganglium. We even know what the memory storage looks like. It's protein molecules coupled up to receptors.”

Dr Pert believes there is “overwhelming evidence” that unexpressed emotion causes illness.

“The raw emotion is working to be expressed in the body. It's always moving up the neural access...up the spinal cord. The need to resist it is coming from the cortex [responsible for thought, perception and memory]. All the brain rationalisations are pushing the energy down. The cortex resistance is an attempt to prevent overload. It's stingy about what information is allowed up into the cortex... The real, true emotions that need to be expressed are in the body, trying to move up and be expressed, and thereby integrated.”

Dr Pert echoed the thinking of three thousand years of holistic healers when she said recently, “I can no longer make a distinction between the brain and the body.”

Today, hundreds of studies are being done along PNI lines, and the US National institutes of Health have established a PNI Institute at Maryland. Professor Ader says that those he calls "card-carrying members of the flat earth society" - scientists who don't believe there are meaningful connections between the nervous and immune systems - "are becoming harder to find".

Already, PNI research is branching out in some surprising directions. Michael Maes, Professor of Psychiatry at the University Hospital of Maastricht in the Netherlands, has discovered fascinating correlations between human immune function and climatic variables such as temperature, sunlight, air pressure, wind speed, humidity and rainfall.

Professor Maes told The Age he and his colleagues have also discovered that “major depression is accompanied by activation of the inflammatory response system”.

At even further extremes, research is being done to find possible links between religious faith and better health. And a hundred New Age sub-disciplines now claim that PNI validates their principles.

Professor Ader, PNI’s progenitor, is dubious about these:

"Because it is such a dramatic illustration of the integrated nature of  adaptive processes, psycho-neuro-immunology has become the scientific umbrella for any number of untested theories and interventions. Also,  the association of PNI with New Age issues only serves to 'turn off' legitimate basic researchers."

Regardless of what’s happening at the fringes, for the first time since the late Middle Ages the “mind-body continuum” is re-entering the mainstream of respectable Western medicine.

If and when its promise is fulfilled, at the minimum PNI will help practitioners to better counsel patients on work and lifestyle, and to more accurately pre-empt the arrival of disease.

“I think most investigators would agree,” says Britain’s Dr Vedhara, “that our 'holy grail' is to establish whether any of this is of clinical relevance. As a psychologist, for me this means: can stress make healthy people ill? Or indeed can stress affect morbidity and mortality in those who already have an illness?”

So far, she says, “The evidence is persuasive, but not unequivocal.”