Causes of Bruxism
Bruxism is a multifactorial condition with psychological stress, anxiety, and depression as the primary drivers, alongside sleep disorders, medications (particularly SSRIs), movement disorders, and behavioral factors, though the exact etiology remains incompletely understood.
Primary Psychological and Psychiatric Causes
Emotional stress and anxiety are the most consistently identified risk factors for bruxism across all age groups. 1 The condition appears strongly linked to limbic basal ganglia dysfunction, particularly in contexts involving anxiety and emotional distress. 2
- Depression is present in approximately 18% of bruxism patients and should be systematically assessed in all cases. 3
- Social phobia specifically predicts the presence of parafunctional oral activity, with severity of social anxiety directly correlating with bruxism risk. 4
- Anxiety disorders are recognized as important contributing factors in adults. 1
- Emotional excitation including rage, fear, annoyance, and embarrassment can trigger or worsen bruxism. 5
- Stress may cause bruxism via activation of neural circuits in the hippocampus and subcortical structures. 5
Medication-Induced Bruxism
SSRIs (selective serotonin reuptake inhibitors) are a well-documented iatrogenic cause of bruxism, typically developing within 2-4 weeks of treatment initiation. 6
- Fluoxetine and sertraline have been specifically reported to induce nocturnal bruxism. 6
- Importantly, chronic SSRI treatment in social phobia patients does not appear to affect sleep or awake bruxism rates, suggesting the relationship may be more complex than initially thought. 4
- Medications that impair cognitive function require caution, especially in elderly patients. 3
Sleep-Related Factors
Sleep disorders, particularly sleep apnea syndrome, are important risk factors for bruxism in adults. 1
- Sleep positioning alterations may contribute to bruxism development. 7
- Sleep disturbances predominate as risk factors in children and adolescents. 1
- In Parkinsonian syndromes, sleep bruxism is mainly observed during non-REM sleep. 2
Movement Disorders and Neurological Conditions
Bruxism appears linked to basal ganglia dysfunction, with higher incidence in hyperkinetic movement disorders. 2
- Awake bruxism is occasionally reported in Huntington's disease, primary dystonia, and secondary dystonia. 2
- The highest incidence and severity occurs in syndromes combining stereotypies and cognitive impairment: Rett's syndrome (97%), Down syndrome (42%), and autistic spectrum disorders (32%). 2
- In Parkinsonian syndromes, awake bruxism is rarely reported but may be exacerbated by medical treatment. 2
- Restless leg syndrome is associated with sleep bruxism. 2
Behavioral and Lifestyle Factors
Consumption of tobacco, alcohol, and coffee are recognized as important risk factors among adults. 1
- Behavioral abnormalities predominate as risk factors in children and adolescents. 1
- Occlusal disorders have been historically associated with bruxism, though this relationship remains controversial. 7
- Allergies have been suggested as potential contributing factors. 7
Developmental and Pediatric Considerations
In children and adolescents, the risk factor profile differs from adults:
- Distress is a primary factor. 1
- Behavioral abnormalities are prominent contributors. 1
- Sleep disturbances play a major role. 1
Important Clinical Caveats
- The etiology of bruxism remains unclear and is likely multifactorial, making it difficult to identify a single causative factor in most patients. 7
- Chronological relationship between life events with psychological repercussions and bruxism onset should be assessed. 5
- Variations in intensity associated with stress are characteristic. 5
- Bruxism that worsens at night or during rest/inaction suggests psychological components. 5
- A biopsychosocial approach is essential, as patients often have other comorbidities including chronic pain elsewhere. 5