When you think of a disability, you may think of a person walking with a cane or sitting in a wheelchair. Surprisingly, some disabilities cannot be seen, including depression and anxiety. People may react to situations in their life differently than you would. Many different things cause anxiety and depression, but the main factor is stress. Some disabilities are physical, while others are mental. Mental disabilities are not always visible. Some people are born with a disability, while others may have developed a disability or had something in life that caused them to have a disability, such as a car accident.