Published by Unseen Progress, an independent publisher of caregiver research. Last reviewed 2026-05-10. Part of the tic disorders research overview.
Short answer. Wax-and-wane fluctuation is a defining diagnostic feature of tic disorders, not a sign that something has gone wrong or that something is working. Tics typically vary in frequency, intensity, and form on a weeks-to-months timescale, with periods of high activity ("waxes") and near-disappearance ("wanes") alternating across the year. Overall severity peaks around ages 10–12 and improves through adolescence in most children. The fluctuation is so reliable that diagnostic criteria for chronic tic disorders specifically include "waxing and waning" of symptoms (Leckman, 2002; Bloch et al., 2006).
The classic Tourette and chronic tic disorder course (Leckman, 2002; Bloch & Leckman, 2009) looks like this:
The wax-and-wane pattern produces several predictable parenting experiences that are worth naming, because each can mislead:
The "we found the trigger" illusion. During a wax, parents naturally look for what changed. Almost always something has changed — a school stressor, a sleep disruption, a new social demand. The temptation is to attribute the wax to that cause. The cause may have contributed, but the underlying wax was probably coming anyway. The next wax usually has a different apparent trigger, which is the giveaway.
The "the treatment worked" illusion. If treatment (medication, CBIT, a school accommodation, a diet change, anything) was introduced near the peak of a wax, the subsequent wane will look like the treatment worked. Some of it might be the treatment. Most of it is probably the wane that was coming. This is why controlled trials in tic disorders need to be controlled — uncontrolled before-and-after data systematically overstates effect.
The "the treatment stopped working" illusion. Symmetrically, if treatment was introduced near the start of a wane and a wax then arrives months later, the wax can look like treatment failure. It might be treatment failure; more often it is the next wax.
The "what did I do wrong" guilt. A wax that follows a parental decision (changing schools, ending a therapy, going on holiday) feels causally linked. Most of the time the link is illusory. The wax-and-wane mechanism does not require an external cause.
The clinical literature is emphatic on these points (Leckman, 2002; Pringsheim et al., 2019): a single uncontrolled observation across a wax-and-wane cycle is essentially uninformative about cause or treatment effect.
The honest answer to "why does this happen" is that the neurobiology is not fully understood. The basal-ganglia and cortico-striatal-thalamo-cortical circuit models that explain tic generation in general terms do not yet explain the timescale of fluctuation. What is known (Leckman, 2002):
What this means practically is that there is no "what we did differently this month" answer to most waxes. There may be contributing factors. There is no single cause.
Given the fluctuation, the clinical literature has developed specific approaches to judging treatment effect (Pringsheim et al., 2019):
Long observation windows. Treatment trials are typically judged at 8–12 weeks at minimum, often longer for medication. Shorter judgements get fooled by the wax-and-wane cycle.
Validated rating scales. The Yale Global Tic Severity Scale (Leckman et al., 1989) is the standard. It rates tics on number, frequency, intensity, complexity, and interference at a single point in time. Repeated YGTSS scores across months produce a more reliable signal than parental impression.
Functional outcomes, not just tic counts. Treatment success is more usefully measured by whether the child can sit through a class, do homework, sleep well, and participate socially — not by whether tics are down 30%. Functional outcomes are less sensitive to wax-and-wane fluctuation than raw tic counts.
Treating the trend, not the moment. Clinicians teach families to look at the trend across multiple months, not the picture of the last week.
The most useful interventions are framing ones rather than mechanical ones (Conelea et al., 2011; Tourette Association of America, 2021):
Name the pattern explicitly. Children who know "your tics will get worse for a while and then better, and that's how tics work" cope with waxes substantially better than children for whom each wax is a fresh crisis.
Resist big decisions during a wax. A wax is not the right moment to start a new medication, end therapy, change schools, or have a difficult family conversation about the tics. Waxes pass.
Avoid attributing the wane to your latest intervention. If you do, the next wax will feel like personal failure when it is not.
Track over months, not days. A simple monthly note — "tics this month: high, mostly motor, sleep okay" — produces more useful pattern recognition than daily counts.
Tell the school about the pattern. Schools that understand the wax-and-wane character of tics respond better to a child whose tics surge in October than schools that interpret the surge as a behavioural regression.
The wax-and-wane fluctuation is, paradoxically, one of the more hopeful features of tic disorders. Waxes pass. Wanes return. Across adolescence, the overall trend for most children is improvement (Bloch et al., 2006). Parents in the middle of a year-three wax often cannot see this; the literature is clear that they should.
For a parent navigating a wax or a wane:
1. Treat wax-and-wane as a feature of the disorder, not a signal about cause or treatment. Most fluctuation has no single external cause. 2. Resist drawing conclusions from a single cycle. A treatment that "worked" during one wane needs to survive the next wax before you can trust it. 3. Make big decisions during stable periods, not during waxes. 4. Track over months. Daily counts amplify noise; monthly notes show signal. 5. Tell the child the pattern. Children who know waxes pass cope with them better than children for whom each wax is novel.
---
Unseen Progress publishes long-form caregiver research and builds research-backed daily trackers for the families covered. See the full tic disorders research overview for the complete framework.