From the outside, the repetitive or ritualistic behaviors that people with OCD have can look like addictions. Both compulsion and addiction create powerful urges that are difficult to resist. If someone cannot engage in them, they may become distressed.
However, compulsions and addiction are not the same.
Compulsions are actions a person feels they must do to avoid negative feelings, such as fear or anxiety. People with compulsions may feel that if they do not carry them out, bad things will happen.
Compulsions can be neutral behaviors, such as counting or tapping. They can even be unpleasant behaviors, such as excessive handwashing that leads to dry, cracked skin.
By contrast, addiction involves substances or behaviors that offer a reward. They may provide pleasure, excitement, or escapism. While they might be harmful overall, the activity itself is enjoyable, even if only temporarily.
So, while addiction is compulsive in that it is difficult to stop, compulsions are not usually addictions.