Bruxism during the day. The ICDS-R defined sleep bruxism as "a stereotyped movement disorder characterized by grinding or clenching of the teeth during sleep", classifying it as a parasomnia. The second edition (ICSD-2) however reclassified bruxism to a "sleep related movement disorder" rather than a parasomnia. Alternatively, bruxism can be divided into "primary bruxism" (also termed "idiopathic bruxism"), where the disorder is not related to any other medical condition, or "secondary bruxism", where the disorder is associated with other medical conditions. Secondary bruxism includes iatrogenic causes, such as the side effect of prescribed medications. Another source divides the causes of bruxism
Bruxism who have sleep bruxism are more likely to also have sleep bruxism than children of people who do not have bruxism, or people with awake bruxism rather than sleep bruxism. Certain stimulant drugs, including both prescribed and recreational drugs are thought by some to cause the development of bruxism, however others argue that there is insufficient evidence to draw such a conclusion. Examples may include dopamine agonists, dopamine antagonists, tricyclic antidepressants, selective serotonin reuptake inhibitors, alcohol, cocaine, and amphetamines (including those taken for medical reasons). In some reported cases where bruxism is thought to have been initiated by selective serotonin