If you grind your teeth at night or catch yourself clenching during the day, it is natural to wonder what is causing it. The frustrating answer is that bruxism rarely has one simple explanation.
Teeth grinding and jaw clenching can be influenced by a combination of stress, sleep physiology, genetics, medications, caffeine, alcohol, smoking and other individual factors. The contributors to awake clenching may also differ from those involved in grinding during sleep.
Bruxism is considered multifactorial. Stress and emotional tension may contribute, particularly to awake clenching, while sleep bruxism appears to involve processes that occur during sleep. Genetics, certain medications and substances, caffeine, alcohol and smoking have also been associated with bruxism. In many people, more than one factor may be involved.
If you are looking for a broader introduction to symptoms, dental effects, evaluation and treatment, start with our Complete Guide to Teeth Grinding and Bruxism. Here, we are focusing specifically on the question of why bruxism happens.
First: Awake and Sleep Bruxism Are Not Exactly the Same
It is tempting to talk about all teeth grinding as one condition, but awake and sleep bruxism occur in different settings and may involve somewhat different mechanisms.
Awake bruxism
Awake bruxism often involves sustained jaw clenching, repeated tooth contact or jaw bracing during waking hours. Some people notice it while concentrating, working, driving, exercising or responding to emotional tension.
Because it occurs while you are awake, behavioral awareness can play an important role. Someone may discover, for example, that they repeatedly hold their teeth together while answering email or concentrating even though they had never thought of themselves as a “teeth grinder.”
For a closer look at daytime patterns, see our guide to daytime bruxism and clenching.
Sleep bruxism
Sleep bruxism occurs during sleep and is less consciously controllable. Research suggests it is related to activity within the sleeping nervous system and may occur around brief changes in sleep state or arousal.
That means nighttime grinding should not simply be explained as “stress coming out in your sleep.” Stress may be relevant for some people, but sleep bruxism is more complex than a subconscious emotional release.
This distinction helps explain why there is no single universal bruxism treatment. The factor driving daytime jaw bracing may not be the same factor associated with someone's nighttime grinding.
1. Stress, Anxiety and Emotional Tension
Stress is one of the factors most commonly associated with grinding and clenching, particularly during waking hours.
People may notice themselves tightening the jaw during periods of concentration, frustration, anxiety or emotional strain. Others become aware of a change only when work, family or life stress increases and jaw fatigue begins to appear.
That does not mean every person with bruxism has anxiety, or that anxiety automatically causes sleep bruxism. The relationship varies by person, and other factors may be involved at the same time.
We explore this relationship separately in Can Stress Cause Teeth Grinding?.
2. Genetics and Family History
Bruxism appears to have a genetic component. Sleep bruxism in particular can occur in families, meaning people with close relatives who grind or clench may be more likely to experience it themselves.
Genetics does not mean that grinding is inevitable. It simply means inherited biology may influence susceptibility alongside environmental, behavioral and lifestyle factors.
If teeth grinding seems common throughout your family, see Is Teeth Grinding Genetic? for a deeper discussion of family history and bruxism.
3. Certain Prescription Medications
Bruxism has been reported in association with certain medications, including some medicines used for depression, attention-deficit/hyperactivity disorder and seizures.
This does not mean that everyone taking these medications will grind their teeth, nor does the presence of bruxism prove that a medication caused it.
Timing can still provide a useful clue. If clenching or grinding begins or becomes noticeably worse after starting a medication, increasing a dose or changing treatment, discuss the pattern with the healthcare professional who prescribed it.
Do not stop or change a prescribed medication because of teeth grinding without speaking with the prescribing clinician.
We cover one commonly searched example in Can Adderall Cause Teeth Grinding?.
4. Caffeine
Higher caffeine intake has been associated with bruxism in some people. Caffeine is a stimulant and can also affect sleep, which may be especially relevant when large amounts are consumed later in the day.
This does not mean that everyone who drinks coffee needs to stop. If you suspect caffeine may be contributing, paying attention to the amount you consume, the time of day and whether symptoms change can be more useful than assuming one cup of coffee is the cause.
5. Alcohol
Alcohol consumption has also been associated with bruxism. The relationship is not as simple as “alcohol causes grinding,” but alcohol can affect normal sleep architecture and may be relevant for some people with nighttime symptoms.
Someone who notices that grinding, jaw soreness or disrupted sleep seems worse after drinking may want to discuss the pattern with a healthcare professional and consider whether reducing alcohol changes their symptoms.
For more detail, see Alcohol and Teeth Grinding: What's the Connection?.
6. Smoking and Other Stimulant Substances
Smoking has been associated with a greater likelihood of bruxism. Other stimulant substances may also influence jaw-muscle activity or sleep.
Because substance effects vary considerably, unexplained new or severe grinding should be discussed in the context of the person's full medication, nicotine and substance history rather than attributed to one factor automatically.
7. Sleep and Sleep-Related Conditions
Sleep bruxism occurs within the broader physiology of sleep, so sleep quality and sleep-related conditions can matter.
Bruxism has been observed alongside conditions such as obstructive sleep apnea. However, the relationship is complex. Grinding your teeth does not mean you have sleep apnea, and a worn tooth or chewed night guard cannot diagnose a breathing disorder.
Symptoms that deserve separate medical attention include loud habitual snoring, witnessed pauses in breathing, gasping or choking during sleep and significant daytime sleepiness.
We examine the distinction in Sleep Apnea and Teeth Grinding: Are They Connected?.
8. Other Health Conditions
Bruxism can occur alongside certain neurological, medical and sleep-related conditions. That does not mean grinding itself identifies any particular disease.
When bruxism appears suddenly, becomes unusually severe or occurs together with new neurological, sleep or other medical symptoms, professional evaluation is more appropriate than assuming the grinding is simply caused by stress.
Does an Uneven Bite or Crooked Teeth Cause Bruxism?
This is an area where older explanations of bruxism have changed.
It was once common to blame grinding on an uneven bite, crooked teeth or minor differences in the way the upper and lower teeth meet. Current evidence does not support dental malocclusion as a simple primary cause of bruxism.
That does not mean your bite is irrelevant to comfort. A newly placed crown, restoration or dental appliance that feels unusually high or uncomfortable may change how you hold or use your jaw and deserves a dental evaluation. But that is different from saying that a person's natural bite alignment is the underlying cause of chronic bruxism.
Bruxism is now understood much more as a behavior influenced by central, psychosocial, sleep-related, genetic and substance-related factors than as a problem that can routinely be explained by tooth alignment alone.
Why Can Bruxism Start Suddenly?
Someone who has never noticed grinding before may suddenly begin waking with jaw fatigue, become aware of daytime clenching or be told by a partner that grinding has started.
When that happens, useful questions include whether anything else has recently changed:
- Has stress or emotional strain increased?
- Have you started or changed a medication?
- Has caffeine, alcohol, nicotine or stimulant use changed?
- Has your sleep changed?
- Are you clenching more while working or concentrating?
- Are there new symptoms such as snoring, daytime sleepiness or disrupted sleep?
These clues can help a dentist or healthcare professional understand the pattern, but they should not be treated as a do-it-yourself diagnostic test.
Can You Have More Than One Bruxism Trigger?
Absolutely. In fact, this is probably a more realistic way to think about many cases.
Someone might have a family tendency toward sleep bruxism, consume substantial caffeine, take a medication associated with grinding and also go through a period of significant stress. Trying to identify one single “root cause” may therefore oversimplify what is happening.
It can be more useful to identify modifiable contributors, watch for patterns and protect the teeth if the forces of grinding or clenching are causing damage.
How Do You Figure Out What Is Causing Your Teeth Grinding?
A dentist can look for patterns of tooth wear, chipped enamel, damaged restorations and jaw-muscle tenderness while asking about the timing of symptoms, daytime habits, sleep, medications and lifestyle factors.
Depending on the circumstances, a physician, prescribing clinician or sleep specialist may also need to be involved.
If you're unsure whether the changes you're noticing are consistent with grinding or clenching, our guide to the warning signs of bruxism explains what to look for.
Does Fixing the Cause Mean You No Longer Need to Protect Your Teeth?
Not necessarily.
Identifying and addressing a contributing factor can be valuable, but bruxism does not always disappear immediately — and in some people a clear modifiable cause is never identified.
When grinding or clenching is already creating tooth wear or putting restorations at risk, a dentist may recommend an oral appliance to protect the teeth while other contributing factors are evaluated or managed.
A night guard should be viewed primarily as protection against the mechanical effects of grinding and clenching, not as proof that the underlying behavior has been cured.
If you're researching protective options, continue with our guide to choosing a mouth guard for teeth grinding and clenching.
Frequently Asked Questions
What is the most common cause of teeth grinding?
There is no single cause that explains every case. Stress and emotional tension are commonly associated with bruxism, particularly awake clenching, but genetics, sleep-related factors, medications and substances such as caffeine, alcohol and nicotine may also contribute.
Can anxiety cause teeth grinding?
Anxiety and emotional stress can be associated with increased clenching or grinding in some people. That does not mean anxiety is responsible for every case of bruxism or that nighttime grinding automatically indicates an anxiety disorder.
Can medication cause bruxism?
Certain prescription medications have been associated with bruxism. If symptoms begin or worsen after a medication change, speak with the prescribing clinician rather than changing the medication on your own.
Does caffeine cause teeth grinding?
Caffeine intake has been associated with bruxism, but individual responses vary. Amount and timing may both matter, particularly when caffeine affects sleep.
Can sleep apnea cause teeth grinding?
Sleep bruxism and obstructive sleep apnea can occur together, but the relationship is complex and one does not diagnose the other. Symptoms of sleep apnea should be evaluated separately by an appropriate healthcare professional.
Can crooked teeth cause bruxism?
Current evidence does not support crooked teeth or ordinary bite misalignment as a straightforward primary cause of chronic bruxism.
Why do I clench my teeth when I'm concentrating?
Some people develop repetitive jaw bracing or tooth contact during concentration, work or other daytime activities. Increased awareness of this pattern can be useful because awake clenching may occur without the person realizing it.
The Bottom Line
Teeth grinding is rarely explained by one trigger.
Bruxism may reflect a combination of psychological, biological, genetic, sleep-related, medication-related and lifestyle influences, and the factors involved in daytime clenching may differ from those involved during sleep.
That is why the most useful question is often not simply, “What caused my bruxism?” but rather, “Which factors may be contributing in my case, which of them can be addressed, and are my teeth being damaged in the meantime?”
A dentist can help evaluate the dental evidence, while other healthcare professionals may be appropriate when medications, sleep problems or other medical factors appear relevant.
Sources & Further Reading
- National Institute of Dental and Craniofacial Research — Bruxism
- Mayo Clinic — Teeth Grinding (Bruxism): Symptoms and Causes
- NHS — Teeth Grinding (Bruxism)
- Journal of Oral Rehabilitation — Research on bruxism and dental occlusion
Editor's Note: This article was updated on September 3, 2026 to clarify current evidence on the causes and risk factors associated with bruxism, distinguish awake from sleep bruxism, remove outdated claims about bite alignment as a primary cause, and separate cause-related education from symptoms, treatment and night-guard selection.
Medical disclaimer: This article is for educational purposes only and is not a substitute for diagnosis or treatment by a dentist, physician or other qualified healthcare professional.