Chronic physical illnesses like heart related disease, diabetes, asthma and risk factors such as obesity, smoking, physical inactivity and heavy drinking are all significantly associated with psychological problems. Psychiatric problems in a person suffering from physical illness may result in increased disability, poor recovery and increased health care expenditure as compared to those suffering from physical illness alone. 
5.1 PHYSICAL ILLNESSES AND MENTAL ILLNESS
The association between chronic physical illnesses and mental illnesses is strong. The history of psychological trauma has been associated with arthritis (joint inflammation and pain), diabetes (increased blood sugar), digestive tract diseases and cancer. Patients with a moderate or severe life-threatening disease are three times at risk for having a psychiatric diagnosis as compared to normal healthy people. Stressful life events are known to play a role in the onset of hormonal. Hormonal disorders may improve with psychiatric treatment for example insulin resistance to insulin may decrease after treatment with antidepressants and similarly, depressive symptoms improve with thyroid hormone replacement. This association is seen in adolescents and children also; adolescents with physical illness have more behavioural or emotional problems and are more depressed compared to normal adolescents. 
5.1.2 NATURE AND TYPE OF ILLNESS IN RELATION TO MENTAL HEALTH
In this section, we will discuss some common and major chronic physical illnesses along with the psychiatric disorders associated with these diseases. 
5.1.3 Heart Diseases
Heart related (cardiovascular) illnesses are the leading cause of death in the industrialised world and are increasing in developing countries. Coronary artery disease (CAD) is a progressive illness characterised by occlusion of arteries supplying blood to heart leading to cardiac ischemia; if not corrected may lead to death. These patients present with complaints of shortness of breath and fatigue, which may be confused with panic or depressive symptoms respectively.