Although anxiety is a normal reaction to stress and can actually be beneficial in some situations, for some anxiety can become excessive. 

And, many find it difficult to control their worry which may negatively affect their day-to-day living.

Also, anxiety disorders frequently co-occur with depressive disorders or substance abuse. 

Anxiety disorders include post-traumatic stress disorder (PTSD), obsessive-compulsive disorder (OCD), and specific phobias to name a few. Collectively they are among the most common challenges one can experience.