Tourette Syndrome (TS) is a neurological condition characterized by sudden, repetitive, non-rhythmic motor and vocal tics. TS is widely perceived as a disorder of childhood, with tics typically emerging during the elementary school years. This leads to the question of whether the disorder can appear later in life, specifically in adulthood. While the formal diagnosis of TS has a strict age requirement, the emergence of tics or tic-like behaviors in adults is a recognized phenomenon that requires careful distinction.
Defining Tourette Syndrome The Age Requirement
A formal diagnosis of Tourette Syndrome is defined by a specific set of criteria that includes an age restriction. According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), the onset of tics must occur before the individual turns 18 years old. For most people who develop the disorder, tics first appear much earlier, often between the ages of four and seven, with symptoms generally peaking around 10 to 12 years of age.
The diagnostic criteria require that a person exhibits both multiple motor tics and at least one vocal tic that has persisted for more than one year. This age cutoff helps distinguish the neurodevelopmental form of the disorder, which is linked to genetic and early-life factors, from other conditions causing similar symptoms later in life. If a person experiences tics for the first time after their eighteenth birthday, they cannot receive a diagnosis of Tourette Syndrome. These late-onset symptoms are instead categorized as a different type of tic disorder, such as “Tic disorder, unspecified,” or a secondary tic disorder.
Understanding Adult-Onset Tics
Tics or tic-like movements that begin after the age of 18 are a clinical reality, though they are not classified as Tourette Syndrome. These late-onset presentations can involve motor or vocal tics, or both, and may be mild or complex. When tics develop for the first time in an adult, they are often referred to as Adult-Onset Tic Disorder or, more commonly, a secondary tic disorder, meaning the tics result from an underlying medical issue.
In some instances, tics that appear in adulthood are not due to an underlying organic cause but are instead functional tics, sometimes known as psychogenic tics. Functional tics are a type of Functional Neurological Disorder (FND) where there is a problem with the nervous system’s function rather than its structure. Unlike tics associated with true Tourette Syndrome, which typically start as simple movements and slowly progress, functional tics often present with an abrupt, explosive onset and are frequently complex and dramatic from the beginning.
Functional tics are also more commonly observed in women and often present in the teenage years or young adulthood, contrasting with the male predominance and early childhood onset typical of TS. People with functional tics may experience a lack of the premonitory urge, which is the uncomfortable sensory feeling that precedes a tic and is reported by most people with TS. Differentiation of these adult-onset tics requires a thorough neurological evaluation to determine if the tics are idiopathic, secondary, or functional in nature.
Causes and Triggers of Adult-Onset Tic Disorders
One category of causes includes specific neurological events that affect the brain’s motor control systems, particularly the basal ganglia. These can include traumatic brain injuries, such as those sustained in a car accident, or conditions like stroke, encephalitis (brain inflammation), or carbon monoxide poisoning.
Tics may also be induced by various medications or substance use, which are often referred to as “medication-induced tics.” Certain medications, such as stimulants used for Attention Deficit Hyperactivity Disorder (ADHD), neuroleptics (antipsychotics), and some antidepressants, have been linked to the development of tics. Similarly, the use of illicit substances, such as a cocaine binge, can act as a trigger for new-onset tics in adults.
Autoimmune and infectious causes are another possible trigger, similar to the childhood presentation of PANDAS/PANS. Common infections can provoke an abnormal immune response that mistakenly attacks healthy brain cells involved in movement control. This autoimmune attack can lead to inflammation and disrupt normal cell functioning, resulting in the sudden onset of tics. Tics in adulthood can also occasionally be the initial symptom of a degenerative or genetic disorder, such as Huntington’s disease.