Tics occur predominantly in childhood and Tourette syndrome (TS) is the most common tic disorder. TS is now thought to be a continuum that includes transient tic disorder (less than a year of symptoms), chronic single-tic disorder (motor or phonic tics, lasting more than a year), and chronic multiple-tic disorder (motor and phonic tics, lasting more than a year).1 According to the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V),2 one of the criteria of TS is its onset before the age of 18. It is unusual for tics to begin in adulthood. The DSM-V classification of tic disorders does not include a category for tic disorders that develop during adulthood, other than tic disorder “not otherwise specified.” In adults presenting with a tic disorder, adult TS is a possibility, and in many cases it represents a re-emergence or exacerbation of childhood-onset TS.3 In the absence of a childhood history of tics, it is important to search for secondary causes, such as central nervous system infection, trauma, cocaine abuse, Huntington’s disease, neuroacanthocytosis and disorders of brain iron accumulation and, most importantly, neuroleptic or other dopaminergic-blocking drug exposure (tardive Tourettism).3 In the absence of an identifiable cause, a psychogenic movement disorder (PMD) must be suspected.
Psychogenic tremor, dystonia, myoclonus, and gait disorder are among the most frequent presentations of PMDs,4 but psychogenic tics have been rarely described in the literature.5 We describe a patient with a chronic phonic tic disorder beginning in her late 50s with clinical clues suggestive of psychogenic origin.
A 67-year-old female had complained of repetitive involuntary vocalizations for 8 years. Initial episodes were infrequent, occurring once or twice per week, and were characterized by involuntary grunting and sometimes shouting. However, vocalizations worsened, becoming more frequent and more intense for 1 year. At the time of consultation, the patient reported several episodes a day. She could not control them, even when she was in public or the focus of attention, and they were not distractible. She reported no premonitory sensations, but admitted a certain relief after the episode. Episodes occurred without a clear precipitant factor. She denied having tics or obsessive compulsive disorder during childhood, which was confirmed after interviewing her older siblings. Apart from candasartan for hypertension, she was not using any medication or illicit drugs. There was no prior history of head trauma or surgery. She denied the use of dopamine-depleting drugs, except for the last 2 months when she was unsuccessfully treated with metoclopramide, domperidone, and chlorpromazine for a misdiagnosis of hiccups. A careful review of her pharmacy record showed no prescriptions of dopamine-depleting drugs. A neurological examination showed grunting and barking vocalizations (Video 1). The neurological examination was otherwise normal and there were no additional abnormal involuntary movements. A psychiatric evaluation showed no evidence of obsessive compulsive disorder, anxiety, and depression. There was no family history of tics or obsessive compulsive disorders. Brain magnetic resonance imaging and magnetic resonance angiography (MRA) were normal, as were echocardiography, pelvic, abdominal, and thoracic computed tomography. The patient was diagnosed with a psychogenic adult-onset chronic single-tic disorder with phonic tics. She was treated with quetiapine 25 mg/day with mild improvement. She did not adhere to psychotherapy sessions, although we had stressed its importance.
Baizabal-Carvallo and Jankovic4 reported on nine cases of psychogenic tics, representing only 4.9% of all patients evaluated for PMD. The mean age of onset in their series was 34.1 years and they found that the lack of premonitory sensations, the absence of tics in childhood and no family history of tics, the inability to suppress movements, and coexistence with other PMDs and pseudoseizures were common in their patients. In their series, two cases started in late adulthood and there was one case in an elderly patient. These were motor tics and they were combined with other PMDs. Our patient had only vocal tics, and they had started at the age of 59 years; after 8 years no other PMDs had occurred. Similarly to their findings, our patient presented with a lack of premonitory sensations and an inability to suppress the movements, which strongly supports a psychogenic origin. The premonitory sensation is considered a hallmark feature of organic tics, and it is reported in about 90% of TS patients.6 Although characteristic of organic tics, premonitory sensations have been reported in patients with presumed psychogenic movements.7 Likewise, patients with TS are usually able to transiently suppress their movements, a feature not consistently present in psychogenic tics.
Some features of our case, taken together, raised suspicion of a PMD: the consistent pattern and severity of the barking sounds; the fact that they have remained the same over many years without changing or waxing/waning; the strained appearance of the patient when vocalizations happen; the fact that there are no other tics, in particular no facial grimacing and no increased eye blinking; the lack of premonitory sensations; and the inability to suppress movements. However, in our case, the patient had no history of psychiatric comorbidity and the tics did not coexist with other PMDs. Additionally, the vocalizations were not suppressible with distraction maneuvers, a characteristic feature of PMD. One might postulate that it is idiopathic instead of psychogenic. Indeed, there are few descriptions of idiopathic adult-onset tics in the literature. In Chouinard and Ford’s8 series of 411 patients with tic disorders, 22 patients presented for the first time with tic disorders after the age of 21. Seven patients (33.3%) were classified as idiopathic adult-onset tic disorder. A chronic single-tic disorder with phonic tics, as in our case, occurred in only one of their series. Sethi9 has reported seven male patients with adult-onset tic disorders: three of them were idiopathic. In their original reports, they do not consider the possibility of a psychogenic origin for the movements.
In conclusion, psychogenic tics are rare and usually a matter of debate. This case is unique in its late adulthood onset of only phonic tics without other PMDs. The absence of childhood and familial history of tics, the exclusion of secondary causes, and the clinical clues such as inability to suppress the movements and lack of premonitory sensations led us to suspect of a psychogenic origin.
1 Funding: None.
2 Financial Disclosures: None.
3 Conflict of Interest: None.
4 Ethics Statement: All patients that appear on video have provided written informed consent; authorization for the videotaping and for publication of the videotape was provided.
We are thankful to Prof. Kapil Sethi for carefully reviewing our paper and suggesting improvements.
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