8. Counting
Some people living with obsessive compulsive disorder seem to take reassurance from patterns or numbers, often doing tasks in specific ways relating to certain numbers, odd/even for example. Even mundane things such as walking down the stairs (counting the steps) or counting how many steps they take from the car to their front door can become quite a chore to someone with OCD. These counting rituals can seem harmless enough, but if you notice a teenager believes that if they do not count to a certain number, or do a task a certain amount of times for fear of something sinister happening, then seeing someone professional may be the best course of action.
