Stratified sampling is often used when one or more of the stratums in the population have a low incidence relative to the other stratums. Convenience sampling is used in exploratory research where the researcher is interested in getting an inexpensive approximation of the truth.
Sometimes symptoms of a mental health disorder appear as physical problems, such as stomach pain, back pain, headache, or other unexplained aches and pains.
Mental Illness Mental illness comes in a variety of forms accompanied by a number of related symptoms. Mental illnesses are some of the most misunderstood afflictions in today's society. Too many people think of mental illness as a weakness. Nothing could be further from the truth. These are true illnesses and brain diseases. Behavioral Health Resources primarily treats the following mental illnesses: Anxiety Disorder Anxiety disorders are the most common and treatable mental health disorders, affecting more than 19 million people a year.