NADD Bulletin Volume I Number 4 Article 1

Complete listing

Etiology and Dual Diagnosis: Notes on a Biologically Based Syndromic Approach

Elliott W. Simon, Ph.D. Brenda Finucane, M.S.

The checkered association between psychiatry and mental retardation has been well documented. In the early part of the nineteenth century people with mental retardation were placed under the care of psychiatrists. There was little differentiation made between people with mental illnesses and people with mental retardation. As the century progressed, psychoanalysis and talk therapy began to dominate the field of psychiatry. People who were perceived as unable to benefit from this therapeutic approach, due to verbal or cognitive limitations, were separated from the mainstream of psychiatry. During this time period, mental retardation vanished from psychiatric training, and for generations psychiatrists did not treat people with mental retardation. This resulted in people with mental retardation being sheltered from any advances in psychiatric diagnostic methodology (Bouras and Szymanski, 1997).

The successful use of antipsychotic medication for schizophrenia in the 1950s and 1960s resulted in the rediscovery of people with mental retardation by mainstream psychiatry. People with mental retardation who were aggressive, self injurious and who had a whole host of other "behavioral diagnoses" were prescribed medication to "treat the behavior". The use of these medications for people with mental retardation without a solid psychiatric methodology in place resulted in many people being sedated as opposed to treated.

Recent advances in diagnosis and treatment approaches for dually diagnosed individuals argue for a syndromic approach to treating mental health disorders in people with mental retardation. This approach places emphasis on determining the presence or absence of a mental illness, the presence or absence of a functional behavioral disorder and generating diagnostic hypotheses in each arena. These hypotheses are then tested through the use of appropriate interventions. In the case of functional behavioral disorders; a functional analysis is performed to drive the treatment plan. In the case of psychiatric disorders, a treatment approach is determined based on the use of medications appropriate to the diagnosis. Medication is used in concert with other interventions which have been shown to be successful in treating the diagnosis (Gardner, 1996, 1997). NADD and its members over the past decade or more have been at the forefront of advocating and supporting the development of a diagnostic methodology which would aid clinicians in appropriate diagnosis and treatment of mental health disorders in people with mental retardation (Reiss & Valenti-Hein, 1990, Matson, 1988).

The above short summary of the relationship between pychiatry, functional behavioral analysis and mental retardation is probably familiar to most readers. As both the psychiatric and behavioral diagnostic approaches look to observable or reportable behavior to generate a diagnostic hypothesis, the role of etiology is underplayed. Given this, and the equally checkered association between mental retardation and genetics, there has been little cross fertilization among the fields of genetic syndrome characterization, psychiatry, mental retardation and functional behavioral analysis.

In the mid 1800s there was a very strong association between behavioral observations and genetic etiology. (J. Langdon Down 1866) used a combination of physical and behavioral features to characterize Down syndrome. During that time, both mental retardation and mental illness were viewed as organically based. With the rise of psychoanalysis, mental health disorders in people with mental retardation became an unfashionable area of study. With the eugenics movement in the late 1800s and the resultant crimes perpetrated on people with mental retardation, such as forced sterilization and segregation in the name of eugenics, the genetics and mental retardation communities likewise became estranged. The rise of an environmentally based approach to mental retardation in the form of normalization and community integration (Wolfensberger, 1972), and the successes of environmentally based behavioral approaches to the training and treatment of people with mental retardation, further estranged the field of genetics and etiologically based diagnoses from mainstream work in mental retardation. Strong negative feelings regarding the association between these two areas still exist today (Gelb, 1998).

The same events which effectively kept psychiatry from developing a system for the diagnosis of mental illness in people with mental retardation also continued to keep genetics out of the mental retardation field. Diagnostic overshadowing, credited for resulting in the under-diagnosis of mental illness in people with mental retardation (Reiss and Szysko, 1983) has also resulted in workers in the field of mental retardation not keeping pace with recent developments in genetics and etiological diagnoses. As Dykens and her colleagues have pointed out (Dykens, 1995; 1996), mental retardation researchers have not used etiology as a unit of analysis to any large extent, preferring to group individuals with mental retardation along the lines of functioning level. This would seem short sighted as roughly 50% of people with mental retardation have some identifiable genetic etiology to their mental retardation (Hagberg and Kyllerman, 1983; Matilainen et al., 1995).

Just as psychiatry is rediscovering appropriate diagnosis and treatment for people with mental retardation and is also forming stronger alliances with the genetics field (Rutter, 1997), genetics is also renewing its acquaintance with mainstream mental retardation. A recent approach to studying the "mental retardation syndromes" (Accardo and Capute, 1998), which bears directly on people with a dual diagnosis, involves characterizing the behavioral phenotype of a specific genetic disorder (O'Brien and Yule, 1995; Finegan, 1998; Simonoff, Bolton, and Rutter, 1998). The term "behavioral phenotype" is used to describe those behavioral symptoms and characteristics, including psychopathology, that characterize a specific genetic or other etiological syndrome. Just as the concept of a behavioral phenotype may be unfamiliar to individuals working in mental retardation, it is also new to most workers in the field of genetics. Although genetic researchers have been characterizing genetic syndromes for years, the concentration has been more on the physical, medical and morphological characteristics of the syndrome rather than on the behavioral or psychopathological characteristics. Given the disastrous results of the eugenics movement, mental retardation and genetics professionals have intentionally shied away from behavioral or psychological characterizations of genetic syndromes.

It would seem, however, that those interested in a syndromic based diagnostic approach would find much to offer in the behavioral characterizations of genetically based syndromes. The genetic approach to diagnosis and characterization of syndromes views both behavioral manifestations and psychopathology as resulting from an interaction of genetic predispositions and the environment. It is not that a behavioral phenotype is viewed as set in stone at conception. It is felt that certain genetic disorders (though at the moment largely unknown pathways) result in behavioral characteristics such as mental retardation or hyperactivity which may come together to form a constellation of symptoms that we have come to term a specific psychiatric disorder. Mental retardation is associated with hundreds of known genetic syndromes. For example, onychotillomania (pulling out finger and toe nails) is a relatively common behavior among people diagnosed with Smith-Magenis syndrome (Greenberg et al., 1991). Missing a part of chromosome 17 does not "cause" this behavior. However, missing a part of chromosome 17 can result in peripheral neuropathy, and this loss of feeling in the fingers and toes is a crucial piece of information to clinicians attempting to treat this behavior.

Advances in behavioral phenotype research occur in two ways: first by studying individuals with known genetic disorders such as Fragile X syndrome and developing syndrome characterizations, secondly by looking for a genetic marker in people with behavioral commonalities. Rett syndrome is a disorder which has long been thought to be genetically based, however, the genetic marker has not yet been found. The behavioral phenotype and developmental course of Rett syndrome has however been well documented (Hagberg and Witt-Engerstrom, 1986). As Rett syndrome has an identifiable phenotype without a genetic marker it remains in the DSM IV as an acceptable psychiatric diagnosis. When the genetic marker is found it will most likely be removed from the DSM IV, as other genetically based syndromes such as Down syndrome or Fragile X syndrome are not included.

Once a diagnosis is made, the most critical test of its clinical utility is whether or not it will drive treatment. An etiologically based diagnosis can and should drive treatment. In many cases a biologically based syndromic diagnosis can serve as a unifying concept among those individuals designing individual supports for a person. It is much easier to develop a unified support system when professionals, the family and the individual are operating from a common unifying concept such as an etiological diagnosis. Aside from aiding in generating functional behavioral and psychiatric diagnoses, the family and individual support available at little or no cost through the many syndrome related support groups is good reason to pursue etiological diagnoses. Mental retardation, functional behavioral disorders, and mental illness are associated with hundreds of genetic disorders. The psychiatric, cognitive and behavioral profiles of these disorders are being better defined on a daily basis. As clinicians working to generate testable hypotheses in the areas of functional behavioral disorders and psychopathology it behooves us to become familiar with the characterizations of some of the more common syndromes.


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Dykens, E. M. (1996). DNA meets DSM: The growing importance of genetic syndromes in dual diagnosis. Mental Retardation, 34, 125-1127.

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Gardner, W. I. (November, 1997). Integrating psychiatric and behavioral diagnoses and interventions: Issues and practices. Paper presented at the 14th Annual Conference of the National Association for the dually diagnosed, Baltimore, MD.

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Greenberg, F., Guzzetta, V., Montes de Oca-Luna, R., Magenis, R. E., Smith, A. C. M., Richter, S. F., Kondo, I., Dobyns, W. B., Pate;, P. I., & Lupski, J. R. (1991). Molecular analysis of the Smith-Magenis syndrome: a possible contiguous-gene syndrome associated with del(17) (pi 1.2). American Journal of Hurnan Genetics, 49, 12071218.

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Hagberg, B. & Witt-Engerstrom, I. (1986). Rett syndrome: A suggested staging system for describing impairment profile with increasing age towards adolescence. American Journal of Medical Genetics, 24 (Suppl 1), 4759.

Matilainen, R., Airalesinen, E., Mononen, T., Launiala, K., and Kaariainen, R. (1995). A population based study on the causes of mild and severe mental retardation. Acta Paediatrica, 84, 261-266.

Matson, J. L. (1985). The psychiatric inventory for mentallv retarded adults test manual. Worthington, OH: International Diagnostic Systems, Inc.

O'Brien, G. & Yule, W. (1995). Why Behavioural phenotypes? In G. O'Brien and W. Yule (Eds.), Behavioural Phenotypes (pp. 1-23).London: Mac Keith Press.

Reiss, S. & Valenti-Hein, D. (1990). Test manual for the Reiss scales for children's dual diagnosis. Worthington, OH: International Diagnostic Systems, Inc.

Reiss, S. & Szysko, J. (1983). Diagnostic overshadowing and professional experience with mentally retarded persons. American Journal of Mental Deficiency 87, 396-402.

Rutter, M. (1997). Implications of Genetic Research for Child Psychiatry. Canadian Journal of Psvchiatry, 42, 569-576.

Simonoff, E., Bolton, P. & Rutter, M. (1998). Genetic perspectives on mental retardation. In J. A. Burack, R. M. Hodapp, and E. Zigler (Eds.), Handbook of mental retardation and development (pp.41-79). Cambridge: Cambridge University Press.

Wolfensberger, W. (1972). The principle of normalization in human services. Toronto: National Institute on Mental Retardation.

For further information contact:

Elliott W. Simon, Ph.D.,
Coordinator, Research and Clinical Service Development
Elwyn Inc.
111 Elwyn Road
Elwyn, PA 19063