The 2025 biographical drama I Swear, directed by Kirk Jones, has brought a renewed and deeply human focus to Tourette’s Syndrome (TS).
By dramatising the life of Scottish advocate John Davidson—who first gained national attention in the 1989 documentary John’s Not Mad—the film strips away the “punchline” trope often seen in cinema.
Instead, it portrays the exhausting physical toll and the profound social isolation that accompany the condition, especially the rare but highly visible symptom of coprolalia.
Tourette’s Syndrome is a neurological “tic” disorder. As shown in the early scenes of I Swear, where a young John (Scott Ellis Watson) begins to lose control of his movements on the football pitch, tics are involuntary and often preceded by a “premonitory urge”—a physical tension that only a tic can briefly relieve.
Causes
While the film focuses on the emotional journey, the biological roots of TS are found in the brain’s “wiring”:
Basal Ganglia Dysfunction: This area of the brain acts as a filter for movements and sounds. In TS, the filter “leaks,” allowing involuntary actions to slip through.
Neurotransmitter Imbalance: Research suggests an overactivity of dopamine, the chemical responsible for signaling movement and reward.
Genetics: TS is highly heritable. I Swear hints at this through the familial tension and the specific ways John’s family reacts to his emerging symptoms.
The film is lauded for its accurate depiction of the “waxing and waning” nature of tics, which can change in severity depending on stress or excitement.
Motor Tics: Simple movements like the eye-blinking and neck-jerking John displays during his school years, or complex movements like hopping or touching objects.
Vocal Tics: Simple sounds (throat clearing, grunting) or complex phrases.
Coprolalia: The film’s title, I Swear, refers to this involuntary use of obscene or socially inappropriate language. Though it is John Davidson’s most famous symptom—famously shouting “F*** the Queen!” during his MBE ceremony—it only affects about 10–15% of people with TS.
TS usually appears in childhood, typically between the ages of 2 and 15.
Sex: Males are 3 to 4 times more likely to be diagnosed than females.
Environmental Triggers: While not a cause, stress and anxiety (like John’s pressure to perform as a goalkeeper) can severely exacerbate symptoms.
Comorbidities: Most people with TS also have ADHD or OCD. In the film, we see how these overlapping challenges make traditional schooling almost impossible for John.
I Swear highlights the evolution of treatment, from the heavy sedation of the 1980s to modern technology.
| Treatment Type | Description |
| Medication | Early treatments often used Haloperidol (as seen in the film) to suppress tics, though these often caused heavy fatigue. |
| Behavioural Therapy | CBIT (Comprehensive Behavioural Intervention for Tics) helps patients “compete” with the urge to tic. |
| Neurotechnology | The film features Neupulse technology—a wearable wrist device that uses nerve stimulation to calm the brain’s motor loops. |
The greatest complication of TS is rarely the tic itself, but the social stigma. John’s journey involves being punched in clubs, arrested by police, and bullied by teachers—all because his tics were mistaken for malice or intoxication.
Interestingly, the tics themselves are often the least of a patient’s worries. TS rarely travels alone; it is frequently part of a group of conditions known as comorbidities:
The good news is that for the vast majority of people, Tourette’s is not a degenerative condition.
The Peak: Tics usually reach their highest severity in the early teen years.
The Decline: By late adolescence or early adulthood, many people see a significant “waning” of symptoms.
Adulthood: About one-third of individuals become tic-free in adulthood, another third see major improvement, and the final third continue to have tics, though they usually learn effective management strategies.
A Note on Coprolalia: Contrary to the “funny” Hollywood trope seen in many films, only about 10% to 15% of people with Tourette’s actually experience coprolalia (involuntary cursing). For most, a tic is simply a shoulder shrug or a throat clear.
As stated above, for many, tics improve significantly in late adolescence. While John Davidson is an example of someone whose severe tics persisted into adulthood, his story—and the 2025 film—proves that with a supportive community (like the “surrogate family” John finds in the film), it is a condition that can be managed successfully.
The 2025 film I Swear serves as a powerful educational tool, shifting the narrative from ‘the boy who swears’ to ‘the man who persisted.’
It emphasises that while Tourette’s is a lifelong neurological reality, the true ‘disability’ often lies in a society that refuses to understand it.
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