What are Mental Disorders by HC120724082921



          (Andrea Scarantino)

         Plan of Today’s Lecture

 1. What is disease?

 2. The causal structure of disease concepts
    and its evolution through time

 3. Mental illness in America: a few estimated

 4. Bibliography:      What     are      Mental
    Disorders? by R. E. Kendell and The
    Concept of Disease: Structure and Change
    by                P.               Thagard
    Concept.html) (optional)

1. What is disease?

Mental disease has never been satisfactorily
defined. The tendency of classificationists of
mental disease has been that of ignoring the
issue altogether or admitting that “there is no
satisfactory definition that specifies precise
boundaries for the concept of mental
disorder.” Kendall proposes to clarify the
issue by first trying to understand what disease
is in general.

Two ways of conceptualizing disease:

 1. Disease as a value-free             concept
    (objectivist approach)

   The concept of disease is biomedical,
   based on scientific facts and not involving
   judgments of value

   a. Disease as structural abnormality
   b. Disease as impairment of function

  2. Disease as a value-laden               concept
     (constructivist approach)

The concept of disease is social, based on
pragmatic objectives and involving judgments
of value

Let us explore the various possibilities.

   Disease as structural abnormality
Disease consists of a demonstrable structural
abnormality of some kind, at the macroscopic
or at the microscopic level

 a. The concept of structural abnormality is
    problematic: in many areas there is no
    standard pattern in relation to which
    abnormality can be defined (e.g. variation
    of heart size, variation of chemical
    constitution of bodily fluids)

 b. The presence of structural abnormality is
    neither necessary nor sufficient for
    identifying disease.
    Not necessary: some common diseases do
    not involve structural abnormality (e.g.
    migraine, schizophrenia)
    Not      sufficient:   some       structural
    abnormalities do not involve disease (e.g.
    fused second and third toes, albinism)

Conclusion: abnormality cannot in itself be
equated with disease.

  Disease as impairment of function
Disease consists of an impairment of the
normal functioning of the organism and its

The concept of normal functioning of the
organism is problematic, especially when the
organism is a human being.
The normal functioning of an animal or plant
is considered impaired when its chances of

survival and reproduction are reduced. But
what about the normal functioning of a human
being? The concept of normal functioning
used in defining disease certainly cannot be
limited to survival and reproduction.
In fact:

     - Diseases do not necessarily involve
       reduction of the chances of survival
       and reproduction (e.g. skin disorders)

     - Reduction of the chances of survival
       and reproduction does not necessarily
       involve disease (e.g. decision of
       abstaining from sex)

 But what do we mean then when we talk
 about human normal functioning? Kendall
 concludes that the answer to this question is
 not easy.

 According to some, the difficulty of defining
 disease as a biomedical concept, witnessed
 by the problems we have discussed so far,

 derives from the fact that the concept of
 disease is inherently social and value-laden.

   Disease as a value-laden concept
Disease consists of any condition that is
considered by the dominant interest groups in
society undesirable and best treatable with
medical means (as opposed for example to
legal means)

According to this view, the boundaries of the
concept of disease vary across time and across
societies and cannot be established in the light
of scientific facts.

 1. There seems to be core of diseases that do
    not vary across time and societies
 2. The concept of normal functioning is not
    necessarily a value-laden concept
 3. To frame the issue merely in terms of
    social desirability seems inappropriate to
    most physicians (e.g. homosexuality)

“It seems clear that most physicians . . .
believe that disease is a scientific term whose
sphere of application should be determined by
doctors on technical or scientific grounds, but
that in practice they apply the term
inconsistently, often in response to what are
quite clearly social or political considerations
of various kinds” (p. 41).

In the absence of an agreed upon definition
of disease, how should we classify mental

Kendall considers four logical possibilities:

     To ignore the problem of definition

This is the strategy used by the World Health
Organization in formulating the International
Classification of Diseases (ICD), the
classification system of mental diseases used
in Western Europe.

    To give a definition vague enough to
     “allow    any     term    with   medical
     connotations to be either included or
     excluded in conformity with contemporary
     medical opinion”

This is the strategy used by the American
Psychiatric Association in formulating the
Diagnostic and Statistical Manual of Mental
Disorders (DSM), the classification system of
mental diseases used in USA.

    To give an operational definition of
     disease that provides unambiguous
     although unsatisfactorily constraining
     rules of application

This strategy has never been adopted

    To       concede     that     “psychiatric
     classifications are not classifications of
     diseases . . . but simply of the problems
     psychiatrists are currently consulted

Kendall thinks the latter is the best strategy, at
least until the concept of disease will have
been clarified.

2. The causal structure of disease concepts
and its evolution through time



     COURSE                   SYMPTOMS


How did the causal structure of the disease
concept change through time?

Theories of Causes of disease       Treatment
Humoral     Imbalance of          Blood letting,
theory (Vth humors (yellow        diet, exercise,
c. BC)      bile, black bile,     ointments etc.
            phlegm, blood)
Germ         Germs (Pasteur,      Starting in
theory       Koch)                1930s:
(1800s)                           vaccination and
Modern       Genetic causes (e.g. Genetic
theories     Down syndrome)       engineering,
(1900s)      Nutritional causes diets,
             (e.g. deficiency of subministration
             vitamin C)           of hormones
             causes (e.g. lupus
             Metabolic causes
             (e.g. diabetes)
             Cytological causes
             (e.g. cancer)

3. Mental illness in America: a few
estimated data

     24% of adults in the US (about 44
  million people) experience a mental
  illness or substance-related disorder
  during the course of any given year.
  The most common of these disorders are
  depression, alcohol dependence, and
  various phobias (irrational fears of things
  or situations).

     14 to 20 percent of individuals
  under age 18 suffer from a diagnosable
  mental disorder. In the United States, an
  estimated 9 to 13 percent of children
  between the ages of 9 and 17 suffer from
  a serious emotional disturbance—that is,
  a disorder that severely disrupts a child's
  daily functioning in the family, school, or

    2.6% of adults in the US (about 4.8
 million people) suffer from a severe and
 persistent mental illness—such as
 schizophrenia, bipolar disorder, or a
 severe form of depression or panic
 disorder—in any given year.

    2.8% of adults in the US (about 5.2
 million people) experience a mental
 illness that seriously interferes with one
 or more aspects of their daily life, such
 as their ability to work or relate to
 other people.

    International surveys have
 demonstrated that from 30 to 40
 percent of people in a given population
 experience a mental illness during their
 lives. These surveys also reveal that
 anxiety disorders are usually even more
 common than depression.


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