Anxiety and depression go hand in glove and usually have a similar effect on people. If a person is suffering from signs of depression he or she will probably also have anxiety. This is one of the most common mental ailments which affect people. Symptoms could be mild or acute and this depends on the severity of the problem. Those who are depressed, feel inadequate and are deep in sorrow most of the time, while those who are anxious suffer with a fear but do not know of what. They just fear an unknown factor and this causes them untold misery. If left untreated the problem could grow and could drive the person to suicide.
An irrational fear and dread is one of the signs of depression as well as anxiety and the person needs help. There are several types of anxiety disorders which affect people. OCD or obsessive compulsive disorder is a form of anxiety disorder which makes the person performs repetitive actions. Different forms of anxiety disorders could be brought on by separation from a loved one, when a drug they are dependant on is stopped like alcohol or even cigarettes and brings on withdrawal symptoms and other factors of stress.
The cause of depression and anxiety can be either physiological or psychological. Treatment for both would differ and would be more symptomatic if it is a physical cause. However, for psychological causes the drugs would be to balance the chemicals in the brain so that the person feels more comfortable. There could be severe physical reactions to anxiety like nausea, sweating, palpitations and other breathing disorders brought on by panic.