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.
Acute mental illness: Comorbid Symptoms. Some of the comorbid or associated medical symptoms for Acute mental illness may include these symptoms: 1  Acute mental health diseases. 2  Acute mental health disorders. 3  Acute mental health problems.