Freedom from Nicotine - The Journey HomeAs teenagers, what most of us thought would be a brief rebellious experiment was quickly transformed into a powerful lifelong chemical addiction as regular nicotine feedings became mandatory. New studies confirm that for some of us it only took coughing and hacking our way through one or two cigarettes before slavery's shackles began to tighten.
Five, ten, fifteen nicotine fixes a day - when would enough be enough? "Tomorrow, tomorrow" became our lifetime cry of millions. Welcome to the realities of true chemical dependency. A world built upon lies.
Science calls our lies denial. Denial is an unconscious defense mechanism - just below the surface - for resolving the emotional conflict and anxieties that naturally arise from living in a permanent state of self-destructive chemical bondage. Three primary areas of denial relied upon by nicotine addicts are dependency denial, cost denial and recovery denial. In each area, truth is sacrificed in exchange for piece of mind while remaining hostage in an artificial world of "nicotine normal" or to justify relapse.
Most nicotine addicts you'll see today are almost completely insulated by a thick blanket of unconscious denial rationalizations, minimizations, fault projections, escapes, intellectualizations and delusions that hide the pain of captivity or create the illusion that the problem is somehow being solved.
The average nicotine addict musters the confidence to challenge their addiction about once every three years, at which time roughly 1 in 20 succeed in breaking free for an entire year. In regard to smokers, by far the most destructive and deadliest form of nicotine delivery, these horrible recovery statistics eventually result in half of us dying by our own hand, each an average of 14 years early. Our senseless self-destruction is undeniable evidence of the depth of denial that insulated us from the extreme price being paid with each puff - a little more of life itself.
The final phase of nicotine dependency recovery is in either allowing sufficient time to pass so that thoughts of wanting to smoke -- reflecting the mountain of denial garbage we constantly fed ourselves over the years -- gradually fade away and stop haunting and replaying over and over in our mind, or accelerating the process by seeing the arrival of each "thought" as a golden opportunity to set the record straight.
Imagine residing inside a chemically dependent mind but not realizing it had grown or activated millions of extra acetylcholine receptors, de-sensitized itself or that nicotine now controlled the flow of more than 100 chemicals inside our body. Many of us didn't need to know that details. We'd already felt punishing anxieties after waiting too long between nicotine feedings. We knew we'd lost the autonomy to simply turn and walk away.
Even though we'd tried to tune it out, we also couldn't help but hear the dull roar of the endless stream of new study findings telling us that each and every puff not only destroyed more of our body's ability to receive and transport life-giving oxygen, but that with it came a greater accumulation of the 81 potential carcinogens identified in cigarettes or the 28 found in oral tobacco. We knew we were slowly building cancer time-bomb within us.
While clinging to the security blanket that all we suffered from was some "nasty little habit," deep down we knew we were hooked solid. So how did our conscious thinking mind cope with the sobering reality that our brain was a slave to its own senseless self-destruction?
How did we look in the mirror each morning and maintain any sense of dignity, self-worth or self-respect while constantly being reminded that we were prisoners to dependency, decay, disease, and that today we smokers would move closer to completing the act of committing our own chemical suicide? It was easy - we learned to lie.
We each called upon our intelligence and conscious mind to help build a thick protective wall of denial that not only insulated us from the hard, cold realities of daily dependency but behind which we could hide when those on the outside felt the need to remind us of who we really were, and what we were doing. Our basic tools for building the wall were conscious rationalizations, minimizations and blame transference.
A pulsating stream of reoccurring urges reminded us that nicotine use was no longer an optional activity. They forced is to explain to ourselves our involuntary obedience to them. We needed to save face. Although nicotine's two-hour half-life was basic clock governing mandatory feeding times, we became creative in inventing alternative justifications and explanations.
In our pre-dependency days (if there were any), we may have found honest pleasure in stealing a nicotine induced dopamine "aaah" sensation accompanied by a rush of adrenaline. But once the feedings became mandatory it didn't matter how we felt about them. Choice was no longer an issue. Even if we didn't fully appreciate our new state of permanent chemical captivity, we rationalized the situation based upon what we found ourselves doing.
Tearing Down the Wall
On Freedom's "Rationalizations" message board (under the heading "Nicotine") we reviewed dignity's wall of illusion, a number of Nicodemon's lies. We learned that there really is no Nicodemon or other monsters, just a chemical. Nicotine is not a friend and using it isn't about love, flavor, pleasure, boredom, concentration, coffee or stress reduction. It isn't about some cute "nasty little habit" but full-blown drug addiction.
Our rationalizations were our defense, insulating us from a harsh world that was often in our face and just wouldn't let up. They were bricks in a wall made thicker by each empty pack, tin or pouch. Our only wall building limitation was our imagination.
But now, here in the final phase of recovery, we must wade back through untold thousands of memories of having rationalized why that next nicotine fix should be administered. It is here that a simple sight, sound or smell may cause old use rationalizations to surface and at times become so thick as to leave us feeling overwhelmed by self induced desires flowing within our conscious, thinking mind.
Have you ever noticed just how challenging it is to coax a smoker or oral user out from behind their wall? After years of construction it tends to be a secure place to hide from those seeking to impose their will upon us.
Frankly, it is not necessary that any of us set out to intentionally dismantle our wall of denial. Time will eventually wear it down so long as we keep our dependency fully arrested. But in that it is simply a reflection of rationalizations we ourselves created, we have it within us to rethink each, thus diminishing or even destroying its impact upon us.
Instead of trying to run or hide from use rationalizations that enter your mind, grab hold of each. Don't let go until you've turned it inside out. Think about the enslaved mind that created it. How much did any of us know about nicotine dependency back then?
Examine each use rationalization closely. Do you recall where it came from? Is that how you felt the very first time you used nicotine? Does tobacco industry marketing play to it? Would relapse somehow make the rationalization permanently go away or only guarantee its survival? Can you say with certainty that it's true and honest, or was it invented by a drug to help justify that next fix?
Whether you choose to attempt to destroy rationalizations or wait for new memories to bury old, the day is approaching when you'll awaken to an expectation of going your entire day without once wanting to smoke nicotine. Oh, you'll still have thoughts now and then but with decreasing frequency, shorter duration and declining intensity. They'll become the exception, not the rule.
They say that "truth shall set us free" but we have an even better guarantee. It is impossible to lose our freedom so long as we refuse to allow nicotine back into our bloodstream. The next few minutes are all that matter and each are entirely do-able. Thoughts or no thoughts, there was always only one rule ... no nicotine today ... Never Take Another Puff, Dip or Chew!
On the "Rationalizations" message board we examined key nicotine use rationalizations. Let's briefly review and add a few more. Why? Because nicotine so invaded nearly every aspect of our thinking that unless we learn to laugh at our excuses they may tend to linger far longer than need be. As mentioned, conscious rationalizations usually fall into one of three categories: dependency, cost or recovery.
Dependency RationalizationsSome rationalized that they used too little to be addicted, lied about how much they used or if addicted that they were somehow better than other users because they used less frequently. But the reason for needing such minimizations was that their chemical servitude was just as profound.
Then we had closet smokers like my grandma Polito who constantly tried to convince us that the thick cloud of smoke rolling out of the bathroom behind her simply wasn't there. How much more visible could denial be?
"I smoke because it gives me something to do with my hands." So is playing with a loaded gun and being a snake charmer, both with less likelihood of death. This weak addiction rationalization ignores that doodling with a pen, playing with coins, squeezing a ball or using strength grippers may be habit forming but are non-addictive. You might get ink on yourself, rich or strong wrists but your chances of serious injury or death are almost zero.
"It's my right to blow smoke!" Truth is, it's your chemical obligation. But as for rights are concerned, don't look now but they're evaporating rather quickly. Social controls to protect the rights of non-smokers are sweeping the globe. If nicotine truly is as addictive as heroin, will society continue to tolerate smoking around children? We are already seeing smoking banned beaches and in parks. It has become an issue in determining which parent obtains custody of the children in divorces and determining parental visitation rights and duties. Increasingly, employers are refusing to hire those dependent upon nicotine.
"I'll cut down or smoke just one now and then." Rationalizations such as this treat chemical dependency as if some nasty little habit capable of manipulation and modification. We are drug addicts and it's as real and permanent as alcoholism. Using less than our level of tolerance will likely leave us in a perpetual state of low-level withdrawal. We may smoke fewer cigarettes but smoke each harder, deeper and hold the smoke longer.
Cost Rationalizations"It's too late now to heal these lungs." Nonsense! Tissues not damaged beyond repair will heal and provide substantial increase in lung function. Even with emphysema, although destroyed air sacs will never again function, quitting now will immediately halt the needless destruction of additional tissues.
"We have to die of something." This rationalization all but admits our own intentional slow-suicide. But try to locate even one terminal lung cancer patient who wasn't horrified at learning that they'd actually succeed.
Some apply the cup half full rationalization that smoking's 50% adult kill rate really means that there is a 50% chance "smoking won't kill me."
" There's still plenty of time left for quitting." Keep in mind that one-quarter of all adult smokers are being claimed in middle age, each an average of 22.5 years early.
"Lots of smokers live until ripe old age." They are more rare than you think. Look around. If you do find old nicotine smokers almost all are in poor health or in advanced stages of smoking related diseases, with many on oxygen. Nicotine smokers tend to think only in terms of dying from lung cancer. Tobacco kills in many ways. For example, circulatory disease caused by smoking kills more smokers each year than lung cancer. Many point to actor George Burns living to be 100. But how long would he have lived and how healthy would he have been if he hadn't smoked cigars? What's wrong with dying healthy?
" I'm only hurting me!" Reflect upon the emotional pain and financial loss your needless dying and death would inflict upon loved ones. How should they explain your death? Was it an accident? Were you murdered? Was it stupidity? Did you intentionally kill yourself?
" A cure for cancer is coming soon." Between Europe and North America, tobacco is expected to claim more than one million victims this year. How many of them thought that a cure was on the way? Sadly, it was false hope. What type of lung cancer are you waiting for hoping they'll cure, squamous cell, oat cell, adenocarcinoma, or one of the less common forms? Even if the right cure arrives, what will be left of your lungs by the time it gets here? If you're gambling on "how" tobacco will kill you, don't forget to consider heart attacks, strokes and emphysema.
"I smoke lights and they're not as bad." Lights and ultra-lights are capable of delivering the same amount of tar and nicotine as regular brands depending on how they're smoked. They do not reduce most health risks including the risk of heart disease or cancer. In fact, their smokers often take longer, deeper drags that may mean more tar and more nicotine not less.
"Quitting causes weight gain and that's just as dangerous." This intellectual denial pre-assumes a large weight gain and then makes an erroneous judgment regarding relative risks. Quitting does not increase our weight, eating does. Some assert that metabolic changes primarily associated with the heart not having to pound as fast could account for a pound or two but as far as being " dangerous," you'd have to gain an additional 75 pounds in order to equal the health risks associated with smoking one pack-a-day.
" It's too painful to quit!" Compared to what? Imagine a diagnosis of lung cancer and having your left lung ripped out, followed by chemotherapy. Imagine years of trying to recover from a serious stroke or massive heart attack, or fighting for every breath through emphysema-riddled lungs as you drag around an oxygen tank for the balance of life.
Recovery Rationalizations"I'll quit after the next pack, next carton, next month, my next birthday or on New Years'" Oh really? Can you count on both hands and all your toes how many times you've lied to yourself with such nonsense? And which pack, carton, month or birthday will give you the best chance for success?
Why did I limit myself to always purchasing only a one days supply? Because tomorrow was always going to be quitting day and I couldn't see me throwing away a carton.
Some of us never made a serious quitting attempt but why? What easier way of ever having to admit chemical dependency or experience defeat.
"I'll quit next week." Some of us pretended that we'd be quitting soon. Some went so far as to actually set a date. It would always make today's nicotine fixes far more tolerable.
"I'm waiting on a cure for smoking." Don't hold your breath. The day science can make our mother's death painless, so as to avoid our sense of emotional loss, is the day it will be capable of erasing the emotional loss associated with ending the most dependable chemical relationship you've likely ever known.
"My family can't handle my quitting." If we failed at quitting we could always reach for this blame transference brick and lay the cause for our defeat upon family members that just couldn't handle the temporary anxieties associated with recovery.
We could blame relapse on friends, a lack of support, a relationship, stressful times, financial hardship, other smokers, alcohol or even our job.
Many argue that they cannot quit because their smoking spouse or friend won't quit too. This procrastination brick allows use to continue until someone else takes action. What if they never quit? How many ride this rationalization to the grave? In relationships, it's great when both can navigate recovery together. But often someone has to be brave, go first, discover how to navigate recovery, show the other freedom's full glory, and then teach them the path home. The "I smoke for love" rationalization is really rather sad.
"My friends all smoke and I'll lose them if I quit." The "I'll be all alone" rationalization shows the depth of dependency. Imagine convincing yourself that if you are no longer addicted to using nicotine that your friends won't want you around, or you won't be able to go around them. Yes, it takes a bit of practice getting comfortable around smokers but extinguishing all "other smoker" cue conditioning is a necessary part of recovery.
"My loved one just died. Now just isn't the right time." Smoking won't bring dad back nor cure any other ill in life. Success during a period of high stress insures that future high stress situations won't serve as justification for relapse.
"I'd quit but withdrawal never ends!" Clearly false. It's the reason for this book.
"If I quit, I'll just start back again. I always do." Truth is, you do not have to relapse. We relapse because we rewrite the law of addiction, we forget why we quit, or we invent lies and excuses such as those that fill this page. This recovery is absolutely guaranteed to be your last so long as nicotine never again finds its way into your bloodstream, so long as you live on the right side of the "Law of Addiction."
Conscious fixation is the ability of the rational thinking mind, our pre-frontal cortex, to become completely engrossed, absorbed and preoccupied with a single subject, issue or train of thought. Unlike a less than three-minute cue triggered crave episode, the product of subconscious conditioning, fixation by the conscious mind can last as long as our ability to concentrate, remain focus and stay absorbed.
When thoughts of "wanting" a nicotine fix begin bantering about inside your mind, will you fixate upon them or instead see the moment as an opportunity for conscious healing? When it happens, a now free mind is granted a chance to analyze the honesty of thoughts and memories created by a drug addict in denial.
Don't worry, neither fixation nor devoting time to analyzing nicotine use related thoughts can harm us. In fact, as Joel likes to remind us, it's impossible to relapse by thinking. It takes acting upon such thoughts to destroy our freedom.
Although unable to erase our drug use rationalizations and memories, we have the ability to paint them with honesty and insights. Such memory recasting can diminish their influence upon us. Instead of an addict's memory becoming fuel for fixation, truth and dependency recovery knowledge can make them laughable reminders of how far we've traveled.
Reflect upon the total number of times as users we likely reached for and relied upon a particular rationalization. The beauty of using each moment of potential fixation as an opportunity to seize, analyze and recast an addict's thinking is that we are not just painting a single memory with truth and insight but possibly thousands.
Although repainting or recasting an addict's memories can accelerate our homecoming, don't allow any remaining addict's thinking to become a stumbling block to contentment. In your mind there may be one or more attractions to nicotine use that truth and insight can't extinguish. If so, accept them, for now, and move on. But in doing so, fit any remaining attractions into the bigger picture.
If willing to be brutally honest about where we once lived, little will remain to embrace. Like eyes on a potato, any lingering romantic use rationalizations will be surrounded by tasty and edible truths. But once home and residing on Easy Street take care not to grow too complacent as an addict's remaining eyes have potential to sprout growth. Every now and then it may be necessary to clean remaining eyes by focus on the bigger picture.
We sometimes encounter long-term former smokers whose remaining use rationalizations are combining with growing complacency to possibly elevate the risk of relapse. Some will disclose that they still think about smoking, with some doing so frequently. When I meet them I attempt to use questions to get them to reflect on the bigger picture.
Almost always, what the long-term ex-smoker would consider an "urge," would bet laughed at by those in the first few days of recovery. Normally it's a brief passing thought that lasts seconds and is quickly abandoned. Digging deeper may allow identification of the particular rationalization that was never confronted with truth while breaking free. It was simply allowed to remain undisturbed and sometimes grow in significance.When was the last time you experienced an urge to smoke?
What thoughts went through your mind?
Why did you want to smoke?
How long did it last?
How intense was it?
Prior to that urge, when was the prior one?
If you don't mind sharing, what did you like most about smoking?
What did you dislike?
Some label nicotine dependency a chronic relapsing condition. But it doesn't have to be. You'll sometimes meet current smokers who'll tell you that they quit once for 5, 10 or even 20 years and then smoked one, and soon found themselves smoking more than ever. Amazingly, if asked, almost all can recall the rationalization they fixated upon in the seconds prior to relapse. Even more frightening, many still believe in the validity of the rationalization that cost them their freedom.
In regard to any remaining romantic nicotine use notions after having bathed them in honesty and understanding, consider this often quoted recovery mantra:
"I'd rather be an ex-smoker
who sometimes thinks about smoking,
than a smoker always thinking about quitting."
The most fatal conscious fixation of all is the fraud of "just one," "just one little puff," "one dip," "one chew," "just once!" A primary maxim of drug addiction is that "one is always too many and a thousand never enough." Instead of picturing just one or just once, try to picture all of them, the return of our entire dependency and the endless chain of feedings that would follow. Why pretend the fiction that we are stronger than nicotine? Why ignore the fact that just one puff will cause up to half of our mind's addiction circuitry to be activated? Why lie to ourselves that our brain soon won't be begging for more? Why waste time being dishonest with ourselves by pretending that a true drug addict can use just one, just once?
"What should I call myself?"
While the exact moment of transition from user to quitter is clear, what do we call ourselves once we have stopped, are we an ex-user or non-user, ex-smoker or non-smoker, an ex dipper or non-dipper? And when is it proper to start doing so? Focusing upon smokers, the choices include non-smoker or ex-smoker. Clearly, non-smoking applies and once quit we are non-smokers. But there is a major distinction between being a never-smoker and non-smoker, a distinction the term non-smoker keeps hidden. Never-smokers need not to be concerned with relapse. Chemical dependency has not permanently grooved and wired their brain for nicotine.
The critical distinctions between never-user, non-user and ex-user apply equally to oral, nasal and transdermal nicotine users. If staying free is important, remembering we are different can serve as a protective self-reminder of vulnerability to relapse.
Both a non-user and ex-user, I will always refer to myself as an ex-smoker or former smoker as doing so reminds me that I remain just one powerful puff of nicotine away from relapse to three packs-a-day.
Initially my mind rebelled against the thought that I was not fully "cured" and not the same as the average never-smoker. It was if I felt I'd earned the right to hide among them. But Joel's online analysis compelled critical thinking. Soon resistance and disappointment passed and I found myself wanting to embrace both the term ex-smoker and the world of ex-smoker-hood. I love my freedom. I love residing on this side of the bars. If true, then why wouldn't I want to remind myself of what it takes to stay here?
If you want to consider yourself a non-smoker or user that's fine. You truly are. But be careful not to totally entrench your thinking in non-smoker-hood as certain legal documents, such as life or health insurance policy applications, may demand disclosure that we are ex-smokers. Failure to fully disclose our prior user status could result in legal or coverage problems.
A related question is when do we become a non-user or ex-user? When do we cross the line? Only you can decide that.
The magic moment when we cross from "quitting" and having "quit" is one of the most wonderful self-realizations of our entire journey home. It's a highly personal moment and different for each of us, the crossing of a self-defining threshold. For me, it occurred when my fears subsided to the point that every fiber of my being knew that this recovery was a keeper. It was then that I knew I wasn't going back.
I'd already told the world I'd quit but the difference this time was that I actually believed it. I had surrendered three decades of control to smoking this chemical. Now, even if tomorrow I were diagnosed with lung cancer, I would take comfort in one sure-fire fact. I would not die with my true killer still circulating in my veins.
The Joy of Smoking?
Out on the town, you watch as your good friend Bill lights-up and **** down a deliciously deep puff, and then lays the pack on the table between you. Cindy, your talkative co-worker, blows smoke your way while gloriously waving her cigarette like a conductor's baton. Arthur and Denise, two smoking strangers, gravitate toward one and other and engage in lite-hearted conversation while guarding a store's entrance. While stopped at a light, Ellen inhales a deep and relaxing puff in the car beside you. "Oh but to again share in the joys of smoking," you think to yourself, "to puff, to taste, to blow, then relax." The joys of smoking? Joy? Joy?
Yesterday, Bill stepped in a pile of dog dung but failed to notice until he turned around and was puzzled by the strange brown tracks across his sky blue carpet that seemed to lead to his right shoe. Bill's sniffer has been almost useless for more than 20 years. A pack and a half a day smoker, he's experienced two cases of pneumonia over the past 3 winters, with the last one putting him in bed for 6 days. Struggling for each breath, Bill still managed to smoke a couple each day. His doctor has pleaded with him to stop but after a half dozen failed attempts, discouragement fills his mind.
Cindy's two teenage sons are onto her almost daily about her smoking. They can't walk anywhere as a family without her cigarette smoke finding the boys. When it does, they make her want to crawl into a hole as they both start coughing and gagging as if dying. When smoking, they never walk together, it's either ahead or behind for lonely mom. She dreads the seven hour drive to her parent's house next week, but she can no longer make excuses for visiting only once in 3 years. Cindy knows that they'll pass three rest areas along the interstate but it will be difficult to fib about having to go to the bathroom at all three. Two will have to do.
The date for the trip arrives. She skips making breakfast to ensure that the boys will demand that they stop to eat along the way. Cindy shakes her head after coming back in from loading up the car. Not only does she have a cigarette in her hand, the ashtray on the table is smoking one too. Before leaving town, she stops to fill up with gas while managing three quick puffs. She feels far more secure after stuffing two new packs into her purse.
Arthur, a 54-year-old two pack-a-day smoker, has large cell lung cancer in the right lobe. The slow growing tumor is now almost five months old and a little bigger than an orange. As he sits rolling coins to purchase his next 46 mg. of mandatory daily nicotine needed to stay inside the comfort zone, he does not yet know he has cancer. Although he has twice coughed up a small bit of bloody mucus, he quickly dismissed it both times.
Frankly, he just doesn't want to know. There is a bit of chest pain but that's nothing new, as chest tightness has occurred on and off for the past couple of years. Additional thick bloody mucus will soon scare Arthur into a doctor visit and a chest x-ray. The delay will cost him a lung. Over the next two years he will battle hard to save his life. In the end Arthur will lose. His fate is the same as what half of all smokers will experience - nicotine induced death.
A workaholic, Ellen has done very well financially. Her life seems to have everything except for companionship. A three pack-a-day smoker, she constantly smells like a walking tobacco factory and often turns heads and noses when walking into a room. A serious chain-smoker, she tells those around her that she enjoys her cigarettes. Deep down, she knows that she is a drug addict and believes that she just can't quit. Her car windows, house blinds and forehead continually share a common guest - a thin oily film of tar and other chemicals. Ellen has a date next Friday, a two pack-a-day smoker named Ed. They'll find comfort in sharing their addictions.
Denise started smoking at age 13 while her lungs were still developing. Constantly clearing her throat, month by month her breathing capacity continues to slowly deteriorate. Smoking lines and wrinkles above and below her lips have aged a once attractive face far quicker than its 32 years. Considered "cool" when she became hooked, the government recently banned smoking in all public buildings. Her boss just posted a new non-smoking policy at work. The headline in the local paper she is holding is about the city proposing a ban on smoking in the park across the street. Feeling like a hopelessly addicted social outcast, a single tear works its way down her cheek.
Fifteen pounds over weight to begin with, a year ago Denise successfully quit for almost 2 months by exchanging cigarettes for a new crutch called food. She threw in the towel when she had outgrown her entire wardrobe. Three months following relapse, and still depressed over her defeat, all the new weight remains with her. Already on high-blood pressure medication, she is about to become a regular user of anti-depressants.
The joy of smoking? Joy?
Fortunately for Denise, a caring friend will tell her about a free online nicotine cessation education and support forum called Freedom. There, Denise will discovery the core principles underlying her almost two decades of chemical dependency upon nicotine. She will successfully arrest her addiction, develop the patience and outlook needed to navigate the temporary period of re-adjustment called recovery, reclaim her self-confidence, and develop the mental skills and healthy body needed to successfully tackle her unwanted pounds, just one ounce at a time.
All that matters are the next few minutes and each is entirely do-able. There will always be only one rule that 100% guarantees success to each of us - no nicotine today!
Exerpts from a free pdf book by Polito JR entitled
"Freedom from Nicotine - The Journey Home"
Copyright 2008 John R. Polito
[font=&] DiFranza JR,[/font] [font=&] Hooked from the first cigarette[/font][font=&], Scientific American, May 2008, Volume 298(5), Pages 82-87.
[/font] Buist AS, The effect of smoking cessation and modification on lung function, The American Review of Respiratory Disease, July 1976, Volume 114(1), Pages 115-122.
 Wald NJ and Hackshaw AK, Cigarette smoking: an epidemiological overview, British Medical Bulletin, January 1996, Volume 52(1), Pages 3-11.