Major and non-major depressive disorders such as depression is fairly common in older adults and have been linked to disability and health decline. Some researchers propose that treatment of depression results in improvement of depressive symptoms and functional outcomes. However, research done in younger adults have shown that people who have a history of depression have a higher likelihood of their health deteriorating, and may develop conditions like metabolic syndrome, cardiovascular disease and diabetes. This corroborates recent studies which have shown that there exists a complex interrelationship between mental disorders and physical diseases and in certain cases mental disorders have been used to predict the later onset of physical disease and vice versa.
Some researchers at the University of Basel in Switzerland discovered that affective disorder significantly increases the risk of developing arthritis and digestive diseases. They found out that people suffering from epilepsy and/or seizures have the risk of having eating disorders increased by more than six folds and that heart disease were markers for anxiety disorders.
The Study investigator of the research, Gunther Meinlschmidt, highlighted the relevance of the research to the treatment of mental disorders and physical illness, as well as the study helping the understanding of their associations.
The research which involved obtaining and analysis of data from the US National Comorbidity Survey Replication Adolescent Supplement were collected between 2001 and 2004 on 6483 individuals aged 13 to 18 years. They used the fully structured World Health Organization Composite International Diagnostic interview and administered relevant questionnaires to the parents or guardians of the participants.
Adjusted discrete-time proportional hazard models were used and the study showed that the onset of mental disorders predicted the onset of physical disorders in several instances. For examples, arthritis, gastro intestinal diseases and skin problems were noted to have been preceded by affective disorders – the risks of which were increased by hazard ratios of 3.36, 3.39 and 1.53 respectively.
Many other temporal associations were noted in which mental disorders predicted the onset of subsequent physical diseases, although the relationships were not significant.
Recent studies report that the health changes were independent of the current levels of depressive symptoms, sleep impairment and mental health functioning, the recurrence of depressive episodes, and the concomitant use of antidepressants. Researchers have also noted that benign depressive episode did not affect the rate of deterioration and the resolution of the depression did not relieve the older adults of the negative symptoms of the depression.
Physiological and psychological mechanisms could be used to explain the link between current depression and decline of health status. First, depression is often associated with changes in lifestyle behaviors such as diet, exercise, and sleep. It is important that, physicians treating older adults should bear in mind that a prior depression history may be a risk marker for physical health decline even when there has been a sustained full remission of depressive symptoms.