Illness Behavior: Coordinate set of non-specific behavioral responses to non-psychiatric illness. These may include loss of APPETITE or LIBIDO; disinterest in ACTIVITIES OF DAILY LIVING; or withdrawal from social interaction.Sick Role: Set of expectations that exempt persons from responsibility for their illness and exempt them from usual responsibilities.Hypochondriasis: Preoccupation with the fear of having, or the idea that one has, a serious disease based on the person's misinterpretation of bodily symptoms. (APA, DSM-IV)Somatoform Disorders: Disorders having the presence of physical symptoms that suggest a general medical condition but that are not fully explained by a another medical condition, by the direct effects of a substance, or by another mental disorder. The symptoms must cause clinically significant distress or impairment in social, occupational, or other areas of functioning. In contrast to FACTITIOUS DISORDERS and MALINGERING, the physical symptoms are not under voluntary control. (APA, DSM-V)Patient Acceptance of Health Care: The seeking and acceptance by patients of health service.Questionnaires: Predetermined sets of questions used to collect data - clinical data, social status, occupational group, etc. The term is often applied to a self-completed survey instrument.Behavior, Animal: The observable response an animal makes to any situation.Feeding Behavior: Behavioral responses or sequences associated with eating including modes of feeding, rhythmic patterns of eating, and time intervals.