CNS Spectr. 2008;13(5):425-432
Faculty Affiliations and Disclosures
Ms. Prado is psychologist in the Department of Psychiatry at the University of São Paulo Medical School, and at the Obsessive-Compulsive Disorder Brazilian Consortium, both in Brazil. Dr. Rosário is psychiatrist in the Department of Psychiatry at the University of São Paulo Medical School and in the Department of Psychiatry at the Federal University of São Paulo. Drs. Hounie, Shavitt, and Miguel are psychiatrists in the Department of Psychiatry at the University of São Paulo Medical School. Ms. Lee is a medical student at Yale University School of Medicine in New Haven, Connecticut.
Faculty Disclosures: The authors do not have an affiliation with or financial interest in any organization that might pose a conflict of interest.
Funding/Support: This study was supported in part by grants from Conselho Nacional de Pesquisa (CNPq) – Process no 133339/2004-1.
Submitted for publication: July 1, 2007; Accepted for publication: April 7, 2008.
Please direct all correspondence to: Helena da Silva Prado, MSc; E-mail: firstname.lastname@example.org.
• Obsessive-compulsive disorder (OCD) is considered a heterogeneous disorder, and the need for identifying more homogeneous subgroups has been emphasized in order to unveil etiological factors and develop more efficient therapeutic strategies.
• A characteristic proposed to evaluate OCD patients associated or not with tics is the presence of subjective experiences, such as the discomfort or uneasiness that may precede or accompany repetitive behaviors.
• Sensory phenomena is relevant for an improved understanding of patients with OCD and Tourette syndrome.
• The worse the sensory phenomena severity, the worse the severity of the obsessive-compulsive symptoms in symmetry/ordering/arranging and counting factors of the Dimensional Yale-Brown Obsessive-Compulsive Scale.
Introduction: A variety of subjective experiences have been reported to be associated with the symptom expression of obsessive-compulsive disorder (OCD) and Tourette syndrome (TS). First described in TS patients, these subjective experiences have been defined in different ways. There is no consensus in the literature on how to best define subjective experiences. This lack of consensus may hinder the understanding of study results and prevents the possibility of including them in the search for etiological factors associated with OCD and TS.
Methods: The objective of this article was to review the descriptions of subjective experiences in the English-language literature from 1980–2007. This meta-analytic review was carried out using the English-language literature from 1980–2007 available on MEDLINE, PsycINFO, and the Cochrane Library databases using the following search terms: premonitory urges, sensory tics, “just-right” perceptions, sensory phenomena, sensory experiences, incompleteness, “not just-right” phenomena, obsessive-compulsive disorder and TS, including OCD and/or TS, in all combination searches. We also searched for the references cited in each article previously found that referred to the aforementioned terms. Thirty-one articles were included in the study.
Results: Subjective experiences, in particular, the sensory phenomena, were important phenotypic variables in the characterization of the tic-related OCD subtype and were more frequent in the early-onset OCD subtype. There is a paucity of studies using structured interviews to assess sensory phenomena, their epidemiology and the etiological mechanisms associated with sensory phenomena.
Conclusion: The current review provides some evidence that sensory phenomena can be useful to identify more homogenous subgroups of OCD and TS patients and should be included as important phenotypic variables in future clinical, genetic, neuroimaging, and treatment-response studies.
Obsessive-compulsive disorder (OCD) is a frequent and clinically heterogeneous condition characterized by the presence of obsessions and/or compulsions that are time consuming and/or cause significant impairment or distress for the patient or their families.1-3
Tourette syndrome (TS) is a chronic neuropsychiatric disorder characterized by an assemblage of motor and at least one vocal tic, with a minimum duration of 1 year.2,4 A tic is a sudden, repetitive movement, gesture, or utterance that typically mimics some fragment of normal behavior. Tics can be suppressed by voluntary effort, but this frequently leads to a heightened emotional state, which is commonly described by patients as an inner energy, pressure, or tense feelings that lead them to perform the tics.2,5
Since the initial descriptions, it has been hypothesized that there is an association between TS and OCD patients.3,6-8 This association has been emphasized more recently by studies reporting that OCD patients with tics present with specific clinical features8-13; a higher risk for first-degree relatives affected with OCD and/or tics14-17; particular neurochemical findings18; and a different treatment-response profile.19,20
Although the current diagnostic criteria1 for OCD and TS consider the presence of obsessive-compulsive symptoms (OCS) and tics as the core clinical features, a variety of subjective experiences have been reported to be associated with the symptom expression of these disorders. First described in TS patients, these subjective experiences have been defined in different ways according to different researchers.13,21-30
The investigation of these different forms of subjective experiences is important for several reasons: both patients with OCD and TS report that such phenomena may cause greater distress than the compulsions or tics themselves3,22; the presence of these subjective experiences may be helpful to identify OCD patients with early onset24 or with OCD associated with tics17,28; a better recognition of the presence of these subjective experiences may increase the patients’ ability to suppress symptoms22; pharmacologic treatment may alter such subjective experiences29; and it is possible that the presence of subjective experiences may be a predictive factor of treatment response.13
Despite its relevance, studies investigating subjective experiences have been limited by the fact that there is no consensus in the literature on how to best define them. This lack of consensus may hinder the understanding of the study results concerning this subject, and bounds the possibility of including them in the search for etiological factors associated with OCD and TS. The main objective of this article is to review all previous descriptions of subjective experiences in order to suggest a consensus definition.
This meta-analytic review was carried out using the English-language literature from 1980–2007 available on MEDLINE, PsycINFO, and the Cochrane Library databases using the following search terms: premonitory urges, sensory tics, “just-right” perceptions, sensory phenomena, sensory experiences, incompleteness, “not just-right” phenomena, obsessive-compulsive disorder, and Tourette syndrome, including OCD and/or TS in all combination searches. We also searched for the references cited in each article previously found that referred to the aforementioned terms.
Criteria for Inclusion/Exclusion of Articles
The inclusion criteria were: articles that presented at least one of the aforementioned terms and defined and/or investigated these subjective experiences in OCD and/or TS subjects. The exclusion criteria were: articles in which the term subjective experiences was mentioned but was not associated with any psychiatric disorders.
A comprehensive database was created including all the potential citations about subjective experiences in OCD, tics, and TS. This database contained 736 references (The Cochrane Controlled Trials Register, Cochrane Library [N=23]; MEDLINE [N=214]; and PsycLit/PsycINFO [N=499]).
After examining the abstracts of the above articles, 32 articles were included in the study. Arranged by methodological design, the articles could be divided as: case-control (13)5,11-13,26,28,31-37; descriptive (8)3,12,21,22,38-41; cohort (1)42; case-study (4)23,43-45; self-report (2)46,47; scale validation (1)48; historical perspective (1)49; review (1)13; book chapter (1).30 For clarity purposes, the articles are presented according to the different types of subjective experiences studied.
Bliss,46 a patient with TS, provided the first comprehensive description of these subjective experiences. He stated that the tics were not the only manifestations of the syndrome, since there were a series of subtle sensations that preceded or accompanied the motor and vocals tics. He named these sensations as “preliminary sensations” or “discrete sensations.”
After this description, many researchers directed their efforts to understand the characteristics and mechanisms of subjective experiences. Shapiro and colleagues30 described “sensory tics” as somatic sensations in the joints, bones, muscles, and other parts of the body. The authors reported that these sensations “evoked a feeling answered by performing an intentional or voluntary movement to relieve the disturbing sensations.”
Concerning OCD, in his 1903 report, Janet50 described patients with feelings of imperfection and incompleteness preceding or accompanying their compulsive behaviors. Similarly, Rasmussen and Eisen38 reported that patients with OCD had an inner sensation that was connected to the wish that things were perfect, absolutely right, or completely under control.
In 1994, Leckman and colleagues51 introduced the concept of “just-right” perceptions, in order to describe the sensation that some patients referred to as not feeling well, balanced, or “just-right”, so that they needed to perform the repetitive behaviors until they felt “just-right.” According to these authors, the patients reported that these sensations were, most of the time, related to visual, tactile, and auditory sensory stimuli.
Summerfeldt39 described feelings of incompleteness as uncomfortable or distressing sensations that did not necessarily trigger the avoidance of a potential damage, but the need to correct feelings of imperfection, or the need for accuracy. The authors reported that these feelings of incompleteness were associated with lower response to cognitive-behavioral therapy.
Miguel and colleagues11 developed a study to investigate what could precede or accompany repetitive behaviors (tics and/or compulsions) and to determine whether these subjective experiences could differentiate patients with tics and/or OCD. They found that OCD patients without TS had a higher frequency of cognitive phenomena (obsessions) and autonomic anxiety preceding their compulsions. On the other hand, OCD patients with TS had a higher frequency of subjective experiences preceding their compulsions, similar to the subjective experiences frequencies in the TS patients. The authors emphasized the idea of a phenomenological continuum between tics and OCS, and proposed that these subjective experiences could be crucial for the identification of OCD subtypes.11,12 Furthermore, the authors emphasized the need for a consensus in the definitions of these subjective experiences and suggested the term “sensory phenomena” as a term that best encompassed all previous descriptions of subjective experiences in the literature (Table 1).
Different descriptions of sensory phenomena include: localized tactile and muscle-skeletal sensations; “just-right” perceptions associated to sensory stimuli such as visual, tactile, or auditory; “just-right” feelings not associated with any triggering stimuli; feelings of incompleteness; energy; and an urge (Table 2). Although imperfect, this term was chosen to encompass all the non-cognitive phenomena associated with repetitive behaviors in these patients.
It is important to mention that almost all published articles presented higher frequencies of sensory phenomena in TS and OCD patients. The only exception was the study by Shapiro and colleagues,30 in which only 4.1% of 1,237 subjects reported sensory phenomena. However, this low percentage may be explained by the fact that only medical records were analyzed without direct interviews of the patients.
These studies2,11-13,21-24,27,30,37,46 exemplify that sensory phenomena are substantially more frequent than expected, and should be included as part of the clinical evaluation of OCD and TS patients. They also cite that a major limitation for a better understanding of these sensory phenomena is the lack of structured interviews for assessing their presence and severity.
As an attempt to overcome this limitation, a group of researchers from the Institute of Psychiatry of the University of São Paulo Medical School and the Massachusetts General Hospital at Harvard University, developed the University of São Paulo-Harvard Interview for Repetitive Behaviors (USP-Harvard), which consisted of questions assessing presence and severity of sensory phenomena, cognitive phenomena (obsessions) and autonomic anxiety symptoms preceding and or accompanying repetitive behaviors.10-12
Thus far, seven studies (Table 3) have been completed assessing sensory phenomena with the USP-Harvard Interview. Miguel and colleagues10,11 reported that OCD patients without tics presented with higher frequencies of cognitive and autonomic anxiety phenomena compared with OCD+TS or TS-alone patients. Furthermore, the OCD+TS group had more sensory phenomena than the OCD group, and the frequencies of sensory phenomena between the TS group and the OCD+TS groups were not significantly different.12
In a later study with the same sample, Miguel and colleagues13 investigated in more detail which kinds of sensory phenomena could differentiate TS, OCD+TS from OCD patients. The authors reported that most types of sensory phenomena were more frequent in the two TS groups (OCD+TS and TS only), when compared with the OCD-only group. These differences were even more striking both tactile and muscular-skeletal/visceral sensations and the less complex sensations, such as “urge only” and/or “energy release”. For example, the need to perform a behavior until feeling “just-right” was reported in 90% of the OCD+TS group compared with 48% of the TS group and 35% of the OCD group. Feelings of incompleteness were even more distinctive in the OCD+TS group. These findings were congruent with those reported by Leckman and colleagues51 in which “just-right perceptions” were found more frequently in TS+OCD patients compared with TS patients without OCD.
To further evaluate this last hypothesis, Diniz and colleagues34 used the USP-Harvard Interview to investigate possible differences in the expression of sensory phenomena in OCD patients without tics (OCD–tics, n=84), OCD patients with chronic motor or vocal tics (n=26) and OCD patients with TS (OCD+TS, n=27). Interestingly, patients with OCD+chronic motor or vocal tics were intermediate between OCD+TS and OCD-Tics patients regarding frequency and severity of sensory phenomena, providing further evidence that sensory phenomena may prove to be useful in subtyping OCD not only as a categorical, but as a dimensional measure. Another study26 investigated differences in the frequencies of sensory phenomena between OCD patients with an early age of onset (<10 years of age) compared with ones with a later age of onset (>18 years of age) of OCS. These researchers found that the early-onset group had significantly higher frequencies of sensory phenomena (both physical and inner sensations), compared with the late-onset group (Table 3).
Other studies5,24,34,44 using the USP-Harvard Interview are described in Table 3. These studies reported that sensory phenomena occurred more frequently in males and among individuals with a family history of TS.12
These results indicated that the presence of sensory phenomena is not restricted to TS patients, and can be an important phenotypic variable in the characterization of the tic-related OCD subtype. In addition, sensory phenomena is also more frequent in OCD subjects with an early age at onset of OCS. Therefore, these results suggest that sensory phenomena could be useful for establishing more homogeneous subgroups of OCD and TS subjects.
Epidemiologic Studies on Sensory Phenomena
To date, there are no epidemiological studies designed to assess these sensory phenomena in the general population published in the literature. Nevertheless, Coles and colleagues27,54 investigated the presence of sensory phenomena in a non-clinical population. In the first study, Coles and colleagues27 applied a questionnaire about perception of everyday experiences to 119 college students. In a later study, Coles and colleagues27 experimentally induced “not just-right experiences” in the non-clinical subjects. In both of these studies the authors concluded that “not just-right experiences” occurred commonly in the population assessed, and that they also can be experimentally induced. However, they do not necessarily cause distress or fear of bad consequences.
Researchers (J. Lee and colleagues, unpublished study, 2007), investigating the role of perfectionism and sensory phenomena in a 44 adult outpatients meeting DSM-IV criteria for OCD and 37 matched controls, found that ~35% of controls reported some form of sensory phenomena but that most of the symptoms did not interfere with daily functioning and caused no distress, fears, or urges. These data suggest that the association of sensory phenomena with OCD also depends on the severity of the sensory phenomena. We may conjecture that there is a continuum of severity between cases and the normal population and that after a certain level, which interferes with daily functioning, the sensory phenomena becomes more associated with OCD.
To date, there are no studies directly assessing etiological hypothesis for the presence and severity of sensory phenomena. The current hypotheses regarding the pathophysiology behind sensory phenomena mostly stem from studies carried out with TS patients. The leading theory involves a hypersensitive gating mechanism in the basal ganglia leading to an overflow of afferent signals to the primary and supplementary motor cortex.57 The hypersensitivity of the basal ganglia is believed to arise from high dopamine receptor affinity in both pre-synaptic and post-synaptic neuronal cells, especially those cells located in the caudate nucleus.23 The downstream effect of the defective-gating mechanism would be an increased activity in the supplementary cortex, as evidenced by PET studies.58 The idea is that the supplementary cortex, an area believed to be involved in movement initiation, becomes overstimulated by the excess of unfiltered sensory input from the thalamus, resulting in the occurrence of these premonitory sensations preceding and/or accompanying the tics. A preliminary study59 showed that subclinical stimulation of the supplementary cortex produced an urge to move.
Implications for Treatment
Shavitt and colleagues55 tried to determine clinical predictors of treatment response in 41 OCD patients treated with clomipramine for at least 12 weeks. The researchers reported that the presence of sensory phenomena was associated with greater decreases of the Yale-Brown Obsessive-Compulsive Scale scores after treatment with clomipramine compared with OCD patients without sensory phenomena. Furthermore, sensory phenomena were present in nine (64.3%) of the 14 OCD patients with tic disorders and in nine (50%) of the 18 patients with early-onset OCD. Conversely, Rosário-Campos and colleagues26 found that the presence of sensory phenomena was associated with a better treatment response in 42 OCD patients. It is important to mention that this study was not prospective and designed to test the hypothesis as did the Shavitt and colleagues5 study. Ferrão and colleagues56 found no differences in the frequencies of sensory phenomena between responders and treatment-refractory OCD patients.
There are few studies evaluating the association between sensory phenomena and treatment response. Nevertheless, it is possible to hypothesize that these sensory phenomena may be useful predictors of treatment response.
This review shows the importance of having a consensus on how to define these subjective experiences and that the term sensory phenomena may encompass all previous descriptions in the literature. It also shows that there is a paucity of studies using structured interviews to assess the presence and severity of sensory phenomena as well as investigating the associated epidemiology and etiological mechanisms.
Future studies are warranted, trying to determine if sensory phenomena can provide valid and reliable indicators of pathophysiology, prognosis, and treatment response in OCD and TS patients. In addition, future studies should investigate if sensory phenomena is prevalent in other psychiatric disorders, particularly in anxiety and impulse-control disorders.
A brief instrument to assess the presence and the severity of sensory phenomena has been developed recently, the University of São Paulo Sensory Phenomena Scale.60 It is based on the previous USP-Harvard Interview. However, even though it evaluates the same information as the USP-Harvard, the University of São Paulo Sensory Phenomena Scale is faster to complete and has simplified structured questions. Currently, there is an ongoing study attempting to determine the psychometric properties for this new scale. Preliminary results (HS Prado, unpublished study, 2008) suggest that the USP-SPS is a valid instrument to evaluate the presence and severity of sensory phenomena in patients with OCD and tic disorder.
The current review provides some evidence that sensory phenomena can be useful to identify more homogenous subgroups of OCD and TS patients and should be included as an important phenotypic variable in future clinical, genetic, neuroimaging, and treatment-response studies.
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