Screening instruments are short and get at the key features of disease. They do not necessarily diagnose a disease, but identify people who need additional questioning or care. Changes in appetite and sleep are symptoms of depression. Hallucinations and delusions, while possible in people with severe depression or mania, are not common and not likely included on a screener. They are more often associated with psychotic disorders such as schizophrenia. Fears are too vague for a screener.