There are many proponents for the breaking down of symptom and behaviour profiles of spectrum disorders, such as Tourette Syndrome and autism (ASD/Asperger's), into discrete 'comorbid' disorders. Despite this tendency, preferred by many psychiatrists/psychoanalysts and to a somewhat lesser extent, neurologists and neuroscientists, substantial evidence for the existence of multiple co-occuring comorbidity, in all cases, is yet to be established convincingly. Clearly comorbidity can and does occur between disorders but can be assumed too readily if definitions are not concise or substantiated.
Symptoms and signs do not directly equate to disorders (a symptom is what a patient experiences, a sign is what a physician observes/elicits). Attention deficit is a symptom but cannot be (definitively) said to represent, or belong exclusively to, Attention Deficit Disorder (ADD) as there are other possible neurological or psychological (and environmental) mechanisms by which attention deficit may occur. Many 'disorders' are 'diagnosed' in a relatively subjective manner, using behavioural checklists and sometimes almost arbitrary fencing off or 'recognition' of perceived symptom groupings. It may not seem important that a person is diagnosed with an inclusive disorder in which the symptoms and behaviours are all seen as a manifestation of that disorder or whether a core disorder is diagnosed along with other separate comorbid disorders. However this does matter in many ways to the patient, their family and especially in terms of medical and other provision they may require. Although a core neuro-developmental disorder has been diagnosed, invariably, and for many disconcertingly, the comorbid disorders are defined as psychiatric.
Non-medical professionals such as teachers, educational psychologists, speech and occupational therapists rely heavily on expert opinion and have built paradigms around specific 'disorders' and the assumed difficulties they represent and hence the ways in which they can be approached. Individuals, their parents and family want to be able to make sense of the diagnoses they have been given and increase their understanding also. Many find an 'alphabet soup' diagnosis of multiple disorders bewildering and confusing. Another concern, especially for Tourette Syndrome, is the disparity in clinical treatment response achieved when those comorbid disorders are treated (in isolation) compared to the responses expected in individuals without Tourette Syndrome with those disorders.
This diagnostic uncertainty and a paucity of underlying mechanisms to explain many of those 'disorders' also has profound consequences for research. Research involves establishing a model for a disorder and then designing data collection and analysis around already established diagnostic categories and criteria. Researchers work on the assumption that what they are looking for and quantifying is real. This breaks down when the diagnostic definitions and symptom-separation may be erroneous, artificial or poorly defined. If TS is perceived as an 'inclusive' spectrum disorder, symptoms, although variable and diverse, will mostly (excepting genuine comorbid symptomatology) be seen as intrinsic to that disorder and suggest appropriate directions for research and help in determining underlying mechanisms for a disorder of greater complexity. However if symptoms such as obsessive and compulsive thinking and behaviours are allocated to a separate disorder (OCD), attention deficit and hyperactivity are allocated to ADD/ADHD, low mood to an affective disorder (depression) or theory of mind difficulties to autism, then clearly the approach will differ markedly. There is much research on TS, OCD, ADD, SPD and ASD, however the boundaries are not as distinct as one might imagine and symptom patterns may be blurred as a number of characteristic symptoms are shared between disorders.
Whether an inclusive (spectrum) or comorbidity (reductive) approach is taken for defining and understanding the symptoms and behaviours of Tourette Syndrome, it is essential that an awareness is achieved of the full range and expression of possible symptoms and behaviours. Many parents of children with a diagnosis are often left without knowing what to expect or why certain behaviours are occurring or whether other children and parents have experienced those issues. In a nutshell, there needs to be an awareness and understanding of the full spectrum of Tourette Syndrome. Parents are frequently informed that one behaviour belongs to Tourette Syndrome but another does not, often without sufficient explanation or worse due to insufficient knowledge of the expert consulted.
Not knowing the 'true' presentation of Tourette Syndrome is a common difficulty for many physicians, therapists, scientists and the public in general. There is some friction between those who have or live with the disorder and the professional 'experts' who differ widely in their understanding and interpretation. One thing that is certain is that people with TS rarely feel that experts fully understand what the disorder entails and fail to have sufficient insight into the existential nature of TS. It is often felt that simplistic and reductionistic explanations are given that do not concur with actual experience. Science and (medical practice) should always be evidence-based but concern is being expressed that too few professionals are familiar with the current available literature and thinking and that uncertainties and errors of definition (especially in diagnostic definition) are undermining the value of research.
Tourette Syndrome is not a 'new' disorder and was described in detail more than a century ago. There is a substantial volume of scientific, clinical and biographical literature but what is lacking is a synthesis. This is, in part, due to a hiatus in objective study of TS during the rise (and subsequent decline) of the Freudian derived school of psychoanalysis/psychiatry which diverged from the neurological research and clinical approaches that once prevailed. This absence of objective research on Tourette Syndrome, during the first half of the 20th Century, was alleviated by the pioneering work of Dr Arthur Shapiro and others during the 1960s.
