Answer:Obsessive and ritualistic behaviour
Explanation:
Obsessive and ritualistic behaviour someone becomes obsessively involved in one action or behavior of their intense interest such that other necessary behavior or bodily needs are neglected which makes this behaviour abnormal. This is common in people with autism spectrum disorder.
The obsessive behavior is usually done in order to reduce anxiety which is associated with impulses to commit to unacceptable behaviour but they end up doing something that increases the impact of their dysfunctional thinking and then it becomes abnormal.