The question of whether Tourette Syndrome (TS) can develop later in life is a common concern for people who experience new tics as adults. The short answer is that a new diagnosis of TS in an adult is not possible under the current clinical definition. Tourette Syndrome is formally classified as a neurodevelopmental disorder, meaning symptoms must begin during the developmental period of childhood. While tics can appear for the first time in adulthood, these cases are categorized differently. These adult-onset tics are often a symptom of an underlying secondary cause, requiring a different approach to diagnosis and management than TS. The strict criteria for TS require onset before the age of 18.
Typical Onset of Tourette Syndrome
Tourette Syndrome is defined by the presence of both multiple motor tics and at least one vocal tic, lasting for more than one year. Tics are sudden, repetitive, non-rhythmic movements or sounds, often preceded by an uncomfortable sensation called a premonitory urge. Tics are categorized as motor or vocal, and can be simple (involving few muscle groups, like eye blinking) or complex.
The typical age for the first tics to appear is between five and seven years old, with severity often peaking around ten to twelve years of age. Simple motor tics, such as eye blinking or facial grimacing, usually manifest first, followed by vocal tics like sniffing or throat clearing. As a neurodevelopmental condition, TS involves abnormalities in brain circuits controlling movement and behavior, which is why it frequently co-occurs with conditions like Attention-Deficit/Hyperactivity Disorder (ADHD) or Obsessive-Compulsive Disorder (OCD).
The natural course of TS often involves significant improvement or even disappearance of tics as a person moves into early adulthood. For a minority of individuals, tics persist into adult life, sometimes waxing and waning depending on factors like stress or fatigue. If tics persist, they are the continuation of a disorder that began in childhood, not a new disorder developing later in life.
Understanding Adult-Onset Tic Disorders
When tics first emerge after the age of 18, they are classified as an Adult-Onset Tic Disorder (AOTD), distinct from Tourette Syndrome. This distinction is necessary because tics beginning in adulthood are more likely to have an identifiable secondary cause, rather than the primary neurodevelopmental process associated with TS. Clinically, these cases often fall under the DSM-5 category of “Tic disorder, unspecified,” since they do not meet the age-of-onset requirement for TS.
This separate classification guides the diagnostic process and helps anticipate possible underlying causes. Unlike TS, which is primarily a genetic condition, AOTD is often secondary, meaning the tics are a symptom of another medical condition or substance exposure. Although AOTD is less common than childhood-onset tics, it is recognized as a significant presentation in movement disorder clinics.
The tics seen in AOTD can be similar to those in TS, involving complex motor movements and vocalizations. However, their presentation may differ, sometimes being localized to one area of the body or following an atypical pattern. The prognosis and treatment approach for adult-onset tics depend entirely on the underlying cause, differing from the established treatments used for childhood-onset TS.
Causes of Tics Starting in Adulthood
The etiology of tics that begin in adulthood often involves an external trigger or secondary medical condition.
Secondary Neurological Causes
Tics can be a symptom of damage or dysfunction in the brain. Examples include tics emerging after a traumatic brain injury or a stroke. Tics can also be associated with specific infections that trigger an autoimmune response affecting the brain’s movement control centers.
Medication and Substance Exposure
This category includes medication-induced tics. A common example involves neuroleptic drugs, which are psychiatric medications that can alter dopamine signaling in the brain. Stimulant medications, often prescribed for conditions like ADHD, can also occasionally trigger or exacerbate tics in susceptible adults. Substance abuse, particularly the use of drugs like cocaine, has been documented as a possible precipitator of new-onset tics.
Psychogenic Tics
Psychogenic tics are not caused by an underlying neurological disease or substance exposure. These tics are considered non-organic, meaning they are not due to a structural problem in the brain, but are instead linked to psychological factors. While a small number of adult-onset tics remain idiopathic (no cause is found), many cases presenting to specialists are symptomatic of one of these secondary conditions.
Diagnostic Distinction Between Childhood and Adult Tics
When an adult presents with new-onset tics, the diagnostic process differs significantly from that for suspected Tourette Syndrome. The first step involves taking a detailed patient history to establish the precise age of onset, which immediately determines if the individual meets the criteria for TS. Clinicians must also investigate any history of subtle, transient tics in childhood that the patient may have forgotten or not recognized at the time.
The next major step focuses on ruling out the secondary causes common in Adult-Onset Tic Disorder (AOTD). This requires a comprehensive medical workup to exclude other movement disorders, such as tremors or myoclonus, which can sometimes be confused with tics. Imaging techniques, such as Magnetic Resonance Imaging (MRI) of the brain, are often utilized to check for structural abnormalities like those caused by a stroke or traumatic injury.
Blood tests are also a standard part of the adult-onset evaluation to screen for various underlying medical conditions, infections, and the presence of certain drugs or substances. For classic childhood-onset TS, these extensive tests are usually not required, as the diagnosis relies solely on clinical observation and history. The thorough investigation in adults ensures that a potentially serious, treatable secondary cause is not overlooked.