Many habits are mentally consuming, and therefor reduce anxiety. Alcohol has a direct effect on self-focused attention. Anxiety is not, in and of itself, maladaptive. In fact, it is not hard to see how animals who are able to experience anxiety and the associated physiological and cognitive features have an advantage. In fact, anxiety may be one of the most adaptive emotions we are equipped with.
Anxious arousal readies an animal for action.
Hypervigillance lessons likelihood that an animal will miss something that could mean death. Strong emotional reaction to danger means an animal will remember what ever caused it in the first place and therefore avoid or prepare for its occurrence in the future. Though anxiety by design is adaptive, there are many people who are crippled by its frequent occurrence. The above model is optimistic, in that any active reduction of a symptom is going to slow down the cycle of anxiety. Knowing which symptoms are tangible and how to reduce their intensity is what cognitive therapy for Anxiety is all about.