A person's emotions and thoughts are greatly affected. Many can't concentrate on anything, have a hard time remembering things, or their decision-making could be impaired. An example of a symptom in a severe case of clinical depression is delusions or hallucinations. If you have many of the above symptoms and they have occurred almost everyday for at least two weeks you may have clinical depression (MDU).
So what exactly causes clinical depression? Unfortunately we don't have a specific answer; all we have are theories to help us understand the cause of depression. Genetics are thought to have some influence over depression. For example, if your mother or father had clinical depression you could very well inherit the mental illness. An example of a psychological influence would be how a person feels about himself or herself. If they don't think highly of themselves they are more likely to fall into depression than someone who has self-confidence. How someone was raised and treated as a child greatly influences whether or not that someone is or will be a victim of clinical depression. Having no mother growing up, battling cancer, and having a spouse pass away are all examples of developmental influences. Of course there are an infinite amount of events that could contribute to clinical depression. Sometimes depression can come out of nowhere even when everything seems to be going good. Still we don't have proof that these theories are correct (ISMHO).
There are only two types of treatment available for this disorder: counseling and medication. There are several types of antidepressant medication used to treat depressive disorders. Many of these medications are supposed to increase the amount of serotonin and dopamine levels produced in the body. Patients often stop taking the medication too soon. This may be because they feel better and they don't need to continue taking the medication, or they might feel like the medication isn't helping at all (ISMHO).