Response to a recent question: Are "ADHD and other 'disorders' comorbid with TS?"
It is unlikely that someone with Tourette Syndrome would not have some degree of attention deficit or hyperactivity - that is the nature of TS. I personally don't believe children or adults with TS always require an additional diagnosis of ADD or ADHD. It is a part of the psychiatric approach to split spectrum disorders into separate 'so-called' comorbidities. The clinical evidence to support this trend is flimsy and often anecdotal and I think in time it will be looked upon as merely collecting or fencing-off symptoms into 'theoretical' disorders (I'm only talking about spectrum disorders here e.g. Autistic Spectrum Disorder, TS etc.).
There appears to be a distinct difference in the way those without TS 'understand' and describe the disorder compared to those who actually have it. Many people (including health professionals) think of uncomplicated TS as being the cause of movement and vocal tics only because that is what they may see or hear. The reality is rather different. The brain does not consist of two disparate disconnected components, the 'mind' part and the part that controls the 'physical' body. The areas that appear to be implicated in TS are central and involved in filtering and selectively responding to and processing incoming neural transmission whether originating from the motor cortex (afferent signals), sensory input (efferent signals) and the intellectual/emotional/memory areas that are involved in thought and cognition. Vocal tics for instance are not just 'mindless' commands to the vocal apparatus to produce noises - they are often cognitively-based and involve both a compulsive urge and a degree of context or thought-derived influences. Many tics are wholly purposeful and involve a high level of awareness, others may occur with little conscious 'thought' involvement. Mind and body are integrated neurologically and externally noticeable tics (not all are easily observed) are just one aspect, and not always the most important, of the high level of 'brain' activity that may be almost continuous. This unseen but nevertheless intrusive activity, is often referred to as 'tics of the mind' although the true meaning of the word tic does not lend itself well to representing these phenomena. Tics of the mind may or may not give rise to behaviour that has a physical expression. What others observe as TS (tic behaviours) is often merely the 'tip of the iceberg'. There is something of an arrogance among others, without TS, in assessing the severity and consequent impact of TS on the individual purely by means of what 'they' can see. They have little or no inkling of what takes place in the mind of someone with TS, and they themselves, in turn, cannot imagine what it might be like 'existentially' not to have a Tourettic mind. There is however often an affinity between people with TS and those who have high-functioning autism, SPD or ADD and an authentic mutual understanding may occur. This is particularly the case with respect to the difficulties shared between the autistic and Tourette spectrums in relation to understanding intentionality, deception and conversational reciprocity (turn-taking) and the initiation, wrapping-up and general protocol of sustainable social interactions. Both are prone to obsessions, perseverating excessively on a favoured topic and not knowing how and when to stop talking. They similarly often fall prey to social 'faux pas' or inadvertently saying the wrong thing.
Much of psychiatry (but less so in neurology) is about theoretical disorders. Psychiatrists do not 'prove' most exist, nor cite any evidence-based mechanisms or investigations and more importantly few will claim to ever having 'cured' a patient of a psychiatric disorder. At a recent meeting of the American Association of Psychiatrists, all who were asked if they could recall ever having cured a patient of a psychiatric illness, responded with the admission that they could not.
It is true that people with ADHD and those with TS share symptoms just as those with ASD and those with TS also share symptoms but symptoms do not make a 'disorder' they are indicative of any underlying pathophysiology, which in most 'psychiatric' disorders is entirely lacking. Both TS and ASD (neurodevelopmental disorders) have strong neuroanatomical and neurophysiological correlates that can often be found on clinical investigation. Evidence suggests people with TS have high brain dopamine activity, especially in the basal ganglia of the brain which plays a role in filtering/inhibiting nerve impulses flowing between the higher cortex of the brain and the body. In TS it appears this function is impaired. TS appears to be a disorder of 'neuro-inhibitory dyregulation' or dysinhibition. People with TS (like those with ASD) may be subject to excessively detailed or hyper-sensitive sensory input which they are unable to filter without conscious intervention or compensatory strategies. Similarly they experience reduced control of impulses and compulsions (e.g. motor, speech, thoughts etc.). There is little requirement for the additional labels of ADHD/ADD. In TS, brain serotonin levels appear to be low and may, in part, be responsible for an increase in obssessive and compulsive behaviours (OCB). Low brain serotonin and nor-adrenaline activity may also, in part, explain a succeptibility to low mood. Here again the additional acronymic label of OCD and also major depression may be applied as if they are discrete but co-occurring disorders rather than symptoms shared by both TS and those disorders.
How many are aware of an individual with TS who does not experience a degree of attention deficit and impaired concentration or who is not somewhat driven, restless and obssessive (hyperactive)? It often goes with the territory.
