A new open access article looking at the issue of addiction
as a brain disease was recently published by Neuropsychopharmacology. The authors point out that since this
original claim as made 20 years ago (7) and subsequently reinforced (8) there have been
a flurry of critical articles. On this blog I have examined several of these
articles in the past. They parallel typical arguments that are used against
psychiatric diagnoses, particularly the concept of psychiatric disorders as
diseases. Interestingly, in this paper
that entire issue was summarily addressed:
“Few, if any healthcare professionals continue
to maintain that schizophrenia, rather than being a disease, is a normal
response to societal conditions. Why, then, do people continue to question if
addiction is a disease, but not whether schizophrenia, major depressive
disorder or posttraumatic stress disorder are diseases?” (p. 3)
Any casual observer of the constant arguments on this issue
will note a constant flux of how psychiatric disorders are described. Disorders, conditions, and constructs come to
mind. I always like to point out that
actual surveys of both the general public and health care professionals finds
that both groups typically classify severe mental illnesses and substance use
disorders as diseases, but to varying degrees.
The best surveys of this problem have been done in Finland (4,5) with
large sample of doctors, nurses, psychiatrists, laypersons, and politicians
included. In two separate studies the
authors asked respondents to consider 60 general conditions and 20 psychiatric
conditions. Respondents were asked to
rank the disorders according to which were more similar to disease conditions
and different cut offs were used for both samples. In the larger survey of 60
medical and psychiatric conditions – schizophrenia and autism met the survey
requirements for disease. In the second
survey, 75% of the respondents considered schizophrenia and autism as diseases
and 50% considered Depression, Anorexia, Panic disorder, Generalized Anxiety Disorder,
Bulimia, Attention deficit hyperactivity disorder, and Personality disorder to
be diseases. There was more disagreement
on Alcoholism and Drug Addiction but 64% of physicians and 74% of psychiatrists
considered alcoholism to be a disease.
On the issue of drug addiction 50% of physicians and 65% of
psychiatrists considered that condition to be a disease. The authors generally
discuss the implications of these opinions from a practical and public policy
perspective rather than a medical or philosophical one. The common arguments
that persist is that disease status confers social legitimacy on a disorder
leading to more treatment resources and hopefully decreasing stigma. In the case of addictions there are longstanding moral defect or choice theories that essentially
equate addiction to willful misconduct. Since large corporations have taken
over the healthcare systems in the United States many of these biases are less
visible since proprietary rules determine who gets treatment resources and how
they are treated. A recent court ruling details how these rules are seriously
flawed (6). An important perspective
from the discussion and that is personal experience with the illness by the
patient, family members, friends, and employers– a subject I will elaborate on
further.
The previous posts on this blog addressed a New England
Journal of Medicine article suggesting that addiction was a problem in
learning rather than a disease in two separate
posts. Before that I addressed a 2015
article that listed 10 reasons why addictions were not a disease.
Responding to these articles highlighted their rhetorical aspect. Many of the arguments against a disease model
of addiction have three basic flaws.
First, they consider the concept of disease to be clearly defined and it
is not. Second, they use their more precise definitions for comparison and as a
way to prove addiction is not a disease.
And third, they suggest that psychosocial variables are relevant only if
the condition in question is not a true disease. They suggest that real diseases are
self-contained and self-perpetuating and that interpersonal relationships and
environmental factors cannot modify diseases.
By extension only a medication or a surgical intervention can modify or
cure a real disease. There are
many examples of diseases that illustrate why that premise is not true. In my practice over the past 30 years the
most common examples have been diabetes mellitus Type 2, hypercholesterolemia,
and hypertension. I have seen many people with extreme cholesterol elevations who
were “cured” by a simple dietary change and starting to exercise. My two previous articles discuss these lines
of argumentation.
Another disease feature of substance use disorders is that
they can occur in discrete epidemics. Although
epidemics are typically thought of as being associated with infectious
diseases, the CDC description is careful to point out that they can also occur
as a result of non-infectious diseases like obesity and diabetes mellitus. They
also describe 5
conditions that lead to epidemics including an increase in
exposure in terms of total amount or increased virulence, introduction of a
novel agent, enhanced transmission, a change in host response, or increased
host exposure that can occur by new portals of entry. All 5 of these factors are relevant in drug
epidemics. Substance use disorder epidemics
have these features as evidenced by the 20-year opioid epidemic that started
with excessive availability of prescriptions opioids and transitioned to more
potent illicit opioids. The widespread availability of these compounds come
from illicit importation and supply chain proliferation often by opioid users
selling these compounds in order to assure that they have an adequate supply. Over the past 25 years there have been a clear
pattern of increased geographic availability of multiple drug classes –
leading to increased morbidity and mortality from substance use disorders in these
areas.
Does the current paper add anything to the argument for
addiction as a brain disease? The authors
review the history of the more public airing of the concept – an original article
by Leshner (7) asserting “addiction is a brain disease” and a follow up article
by McClellan (8). The fact that both of these declarations are only about 20
years old should not be lost on anyone. The authors get derailed from the basic
concept of disease in the very next paragraph by suggesting “To promote patient access
to treatments, scientists need to argue that there is a biological basis
beneath challenging behaviors of individuals suffering from addiction.” The social utility of a diagnosis is separate
from its medical and scientific utility. All three are conflated at times (even
to the point of suggesting that laypersons should have input into what is a
diagnosis), but in my opinion without medical and scientific utility – there is
not social utility.
They review the definition of disease – starting with
Jellinek’s “The Disease Concept of Alcoholism”.
Jellinek made the argument that diseases were not self-contained
“entities” but it is more of an agreed upon label “to describe a cluster of
substantial deteriorating changes in the structure or function of the human
body and the accompanying deterioration in biopsychosocial functioning”. That definition is very close to the one I
came up with reviewing the work of philosophers Munson and Resnick who
defined disease as a “failure of normal functioning”. The main difference is
that these two philosophers predicated the definition on the premise that
biological systems were programmed processes and those processes failing is
what causes the disease. Adaptive reward based learning can certainly be considered a programmed process in brain biology.
They take a close look at the idea that any definition of
addiction should account for spontaneous remission and non-relapsing states.
One of the typical arguments against addiction as a disease is that a
significant number of heavy drinkers (and probably cannabis smokers) stop after
they graduate from college. In many
ways, excessive alcohol and drug use in college is considered a rite of passage
by many Americans. That rite of passage
has a considerable mortality and morbidity on its own that is usually not
considered by the addiction as disease critics.
The vast majority of these people are not the people seen by
addiction specialists later in life. The people seen in their 40s or 50s will
typically give a history of knowing that their pattern of drinking was
problematic. As an example: “I knew from
the very first time that I drank a lot more and I drank faster than anyone
else. I drank more in college and I did not stop after I graduated”. And they elaborate on the consequences of
excessive alcohol use at every life stage.
Binge use or even fairly continuous use of drugs or alcohol in college
is not the same as an addiction.
The authors point out that some of the epidemiological data
used to justify the remission argument is dependent on methodology and
population. For example, a population
recruited from a residential treatment facility and interviewed with a
standardized interview will yield much different results than a community
sample. The diagnosis of addiction (or severe alcohol use disorder) will be stable
in the former case but not the latter.
They reference NESARC (National Epidemiological Survey on Alcohol and
Related Conditions) as the community sample and using that methodology the
baseline lifetime prevalence of non-remitting alcohol dependence was 10% (p.
9). They also point out that opioid use
disorder when observed for 10-30 years has a stable abstinence rate of <
30%. The fact that some people stop
using excessive amounts of drugs or alcohol is not an argument that there is not
a large population of people who clearly have a chronic relapsing course and
incur significant mortality and morbidity along the way.
The authors proceed to the genetic argument and point out
that family and adoption studies point to a heritability of ~50% for addictive
disorders. They highlight typical misunderstandings of genetics,
specifically the concept of polygenic risk and that fact that some polygenic
disorders lead to pathological states – addiction being one of them. An additional argument is that although the
first 20 years of human genome study have been very productive for Mendelian
disorders, it has been far less productive for more complex disorders (11).
Understanding the human genome is far from complete at this point and some
research groups are just beginning to understand the relationships between
genetics, addiction, and medication effects (12, 13, 14).
The lesion argument is the next disease straw man to
fall. It should be obvious to anyone that diseases do not necessarily produce a
discrete lesion either on imaging studies or autopsy. An yet it remains a favorite to anyone who claims
that addictions or psychiatric disorders are not diseases. They review how imaging is currently used
clinically. This is a reality that most
of the critics seem to miss. If I see
brain imaging consistent with small vessel ischemic disease – that alone is
insufficient to make the diagnosis. It also requires an adequate history and
examination of the patient. The critics apparently have not see radiology
reports that point out “clinical correlation is necessary”. The authors briefly review the functional
imaging of alcohol and stimulant use disorders that point to problems with
frontal-striatal circuitry, structural changes with alcohol, and demonstrable
and expected changes in dopamine signaling. Brain imaging in addiction at this
point (apart from the necessary clinical imaging) is useful from a heuristic standpoint
– looking for relevant mechanism and treatments, but there is no imaging of
addictive disorders per se.
A popular viewpoint these days is that there is not enough
of an investment in psychosocial factors in funded research. Many of those critics
make the argument that the trade off should be reduced funding for biological
research and those funds should be diverted to psychosocial research. The
authors here acknowledge the importance of social factors, their incorporation
in more complex research designs, and the fact that a view of addiction as a
brain disease in no way negates the importance of other environmental
factors.
The authors address the issue of reductionism. They use the term determinism instead. Over
the past two decades molecular biologists have moved firmly away for the idea
that all complex biological systems can be reduced to the basic laws of chemistry
and physics. The does not mean that with the appropriate tools biological complexity
can not be understood and explained. Many
physicists see the brain as deterministic.
In other words because the brain is made up of particles and those
particles must follow the laws of physics, the future (or past state) of any
brain can be determined by the right differential equation. Deterministic
states can be chaotic and in that situation they are not predictable. If you believe the brain is deterministic based
on physical laws – it follows that there is no free will and that free will is
an illusion. The real limiting factors
with describing the brain as deterministic include the following problems:
1. There are known stochastic factors that introduce random events – some of which are relevant for the
addiction.
2. Complexity – as noted
above. There is so much structure and so
many particles that must be considered in these complex systems that there is a
clear measurement problem and the most difficult problems are solved by
computer modeling approximations rather than mathematically. I have not seen it discussed but whenever I consider the complexity of biological systems, I see them as an almost infinite set of microenvironments - each with their own physical and chemical parameters. If there was an equation to describe all of those microenvironments acting at one - it would be exceedingly complex.
3. Brain changes occurring
during the addiction process (a large number of which are unknown at this time)
alter the deterministic nature of the system. I suppose the response by the physical determinists would be that the new altered system would be determined by the laws of physics and chemistry. That does not alter the fact that it is a new system with different physical and chemical componenets.
The authors contend that the system is indeterministic
because of these factors and therefore free will is allowed. An associated physics and philosophical
question is whether it is really deterministic but unpredictable and why. Overall,
these philosophical arguments do not really seem to add much to the debate. The critical piece is whether either deterministic
or reductionist is used in a pejorative manner.
That use is typically coupled with arguments that other social or psychological
theories is what is really happening. Scientists and physicians are generally
interested in knowing all of the details and mechanisms of action. The is the
real driver of knowing what is happening at the molecular level. This paper does a good job of explaining why
people who use that approach do not exclude everything else that is going on in
the environment.
They end on the issue of compulsivity (or more accurately
uncontrolled use) in addiction. It is not the case that this does not happen,
but the degree at which it happens. In
the people who I work with practically all of the negative outcomes are
associated with uncontrolled use/compulsivity.
That does not mean that people with addictions are automatons. The major treatment modality anywhere is some form of group therapy. Those groups would not exist if there was an assumptions that people with substance use disorders could not choose to change their thought patterns and behavior. They
continue to have some flexibility, but the probabilities during an active
addiction is that the substance use will continue despite negative and in many
cases life threatening outcomes. Intact decision making in other areas or even
in the focal area of continued substance use with episodes of abstinence does
not mean that normal decision making occurs in all areas of life.
In their conclusion, the authors suggest that progress can
occur from integrating a number of scientific perspectives including those
outside the field of neuroscience. They
advocate for consilience and input from a plurality of disciplines. They also
suggest that no single discipline has exclusive ownership of the field.
As a clinician who is used to constant criticism of
psychiatry from people who don’t know anything about it – I have a different position. First,
we need to acknowledge the severity of addictions specifically that they kill and disable
large numbers of people. Family members trying
to help an afflicted persons know that as well as the difficulty in trying to
help them stop. Second, in rankings of disability compared with other disease states – addictions are consistently
in the top 10. When combined with
psychiatric diseases they are ranked second. There are few other diseases as disabling or lethal. Third, there have been treatments that are based on the underlying
biological factors that are thought to be relevant to addiction that have
worked. Four, it is very clear that individuals
with addictions are no longer functioning normally – defined as their normal
baseline. That can start at any point in
the life cycle – and at some point most people are aware that they have a
severe problem and cannot stop.
All of those factors point to a disease state and it is
good to see a paper supporting that opinion. But
even beyond this opinion, consider the people you have known with addictions
and make up your own mind based on that experience. Carefully consider how you interact with people if you consider addiction to be a disease or intentional decision-making.
George Dawson, MD
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