Allen Frances, MD, identifies a number of concerns about the draft DSM5 revisions.1 Not mentioned in his commentary, but of significant concern, is a proposal that might subsume tic disorders under a new category called “Anxiety and Obsessive-Compulsive Disorders” (AOCD) if the existing Childhood Disorders group is eliminated. By the Task Force’s standards, the proposal represents a significant change and as such, the guidelines for DSM5 revision require more evidence than would be required for a minor change.2 While I appreciate the work group’s diligent efforts, sufficient validators do not exist to support the proposal, the proposed grouping would not improve patient treatment, and any such grouping potentially harms individuals with tic disorders.
As a matter of face validity, including tic disorders under AOCD seemingly suggests that at the very least, the vast majority of individuals diagnosed with a tic disorder will have significant anxiety or obsessive-compulsive features. Neither anxiety nor obsessive-compulsive symptoms are required for diagnosis of any tic disorder,however,and the work group’s review of research does not cite any research demonstrating an association between tic disorders and anxiety or OC symptoms for any tic disorder other than a subgroup of individuals who have Tourette’s Disorder (TD).3 Overall, what percentage of individuals with tics have either anxiety and/or obsessive-compulsive features? With the exception of TD, we really have no research answering that question. Even though the TD+OCD subgroup of TD is a clinically important and large subgroup and there is evidence of some genetic linkage between TD and OCD for a subgroup of individuals with tics, evidence for a majority of cases and for all tic disorders should be required to support the proposed grouping.
In addition to the absence of adequate comorbidity evidence that should be available to support a grouping under AOCD for non-TD tic disorders, neither neuropsychological,neurochemical, nor neuroanatomical research on TD provides adequate and differential support for grouping tic disorders under AOCD. Indeed, to some degree, and as the work group properly noted, neuropsychological findings and neurochemical differences tend to argue against any such grouping.
One other line of evidence the work group considered relates to phenomenological similarities. Specifically, the premonitory urges and “just right” phenomena in TD appear similar to and may be part of a spectrum that could include tics and OCD. Preliminary research suggests that for children over age 10, premonitory urges correlate with tic severity, anxiety/depression, and OC symptoms.4 Most young children with tics do not report any premonitory urges, however. Where is the phenomenological aspect for children under 10 that might support the proposed grouping?
From a treatment perspective, grouping tic disorders under AOCD does nothing to improve pharmacological treatment of patients because AOCD primarily implicates the serotonin system while tics primarily implicates the dopamine(Drug information on dopamine) system. In terms of nonpharmacological treatments, cognitive-behavioral therapies have been successfully used with AOCD conditions as well as tic disorders, but that similarity is not particularly significant when one considers that cognitive-behavioral therapies have also been successfully used with depression and other non-AOCD conditions. In A Cursing Brain? Histories of Tourette Syndrome, Dr Howard Kushner describes the ineffective treatments that were offered to patients when tics were viewed as psychological symptoms representing anxiety or neurosis.5 Do we really want to return to those days or increase the risk of patients being told that their tics are a manifestation of anxiety when they are not?
One of my biggest objections to the proposal is that the proposed grouping may foster misunderstanding of children with tics by school personnel. After 20 years of advocacy, many, if not all, schools now recognize tics as a neurological symptom that may be exacerbated or ameliorated by school environment and other factors. If teachers now hear that tics are an anxiety or OCD disorder, what impact will that have? Will teachers simply tell the child to stop worrying instead of providing accommodations for tic-specific interference? Will children with tics be placed in school-based support groups with peers with anxiety disorders who learn techniques that may not be effective for tics? And will employers be as inclined to grant adults with an uncomplicated tic disorder reasonable accommodations if they view tics as an anxiety or obsessive-compulsive disorder instead of viewing it as a neurologically based problem with motor regulation?
In the absence of sufficient genetic, neurological, neuropsychological, and clinical evidence that demonstrates association between anxiety or obsessive-compulsive disorders and tics for the majority of individuals across all tic disorders, in the absence of any anticipated therapeutic benefit of such grouping, and in light of the risk of potential adverse consequences of the grouping, tic disorders should be left as their own group. That said, it might be useful to add a specifier to TD. Just as the work group recommends adding a specifier to OCD for “tic-related OCD,” why not add a comparable specifier to tic disorders such as “with OC features” or “OC-related tics?” Adding specifiers could facilitate research that might help clarify the extent to which anxiety and obsessive-compulsive features are present in a variety of tic disorders while preserving tic disorders as their own unique group.