Tourette syndrome does not have one 'specific' symptom profile that is represented in all individuals although the presence of motor tics for twelve months or more accompanied by 'vocal' tics is the defining feature in diagnosis. Some domains may be more represented in some or be of lesser significance in others. Evidence suggests that there may be several different 'phenotypes' of Tourette syndrome although these have proved difficult to define conclusively.

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One of the most significant axes is the relationship between tic behaviours and obsessive-compulsive behaviours (OCB). Much debate continues with respect to TS-related OCB/OCD and OCD. There are several perspectives. One is that TS and OCD are manifestations of a spectrum disorder with a common neuro-pathological/genetic origin. Another is that TS-related OCB is possibly intrinsic to TS itself but shares an area of over-lapping neuro-pathology, and thus symptomatology, with OCD.

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It is also becoming more apparent that a possible relationship with autistic specrum disorder may exist. Although some people with TS also receive a diagnosis of ASD it is known that a high proportion of those with a primary diagnosis of TS have some symptoms that are shared with ASD and once thought to be characteristic only of ASD. These include 'Theory of mind' and social difficulties. However it should be noted that these neuro-developmental 'disorders' are mostly defined only by observed signs and symptom sets and their underlying physiological/anatomical cause is unknown and thus no investigative tests are available.

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Sometimes responsiveness to specific drug therapies may help increase the strength of a diagnosis. Many neurological (and especially psychiatric) disorders are diagnosed using numerical scoring algorithms based on a relatively subjective 'grouping' of symptoms. Much current work focuses on determining the actual neurophysiological aetiology of neuro-developmental conditions such as TS, autism (ASD), ADD/ADHD and SPD in order to establish better diagnostic definition that includes investigative pathology and so reduce the ambiguities of subjective/intuitive assessment.