Depression was always considered as a mood disorder characterised by feelings of sadness, low self-esteem and aversion to activity that can affect a person’s thoughts, behavior, feelings and sense of well-being. While clinical depression was a more severe form of depression marked by persistent low mood throughout the day.
However, a team of researchers from the University of Granada (UGR) have proved scientifically for the first time that depression is more than a mental disorder. It causes important alterations of the oxidative stress, and hence should be considered as a systemic disease (something that affects a number of organs and tissues), since it affects the whole organism.
Their work was published in the renowned Journal of Clinical Psychiatry.
Free radicals are reactive oxygen species and reactive nitrogen species that are constantly produced by our body during its day-to-day activities such as metabolism and other endogenous systems, as well as in certain disease conditions. These free radicals are generally balanced by the antioxidants present in our body, and a proper balance between them is essential for proper physiological function.
If the balance is skewed, the free radicals accumulate and cause a condition known as oxidative stress. The new study suggests that depression could lead to skewing this balance towards oxidative stress.
The present research is a meta analysis of 29 previous studies comprising 3961 people, and explains in detail what happens in the organism of people suffering from depression.
It studied the imbalance between the individual increase of various oxidative stress parameters (especially malondialdehyde, a biomarker to measure the oxidative deterioration of the cell membrane) and the decrease in antioxidant substances (such as uric acid, zinc, and the superoxide dismutase enzyme).
The researchers managed to prove that after receiving the usual treatment against depression, the patients’ malondialdehyde levels are significantly reduced, to the point that they are indistinguishable from healthy individuals. At the same time, zinc and uric acid levels increase until reaching normal levels (something that does not occur in the case of the superoxide dismutase enzyme).
This work could explain the significant association that depression has with cardiovascular diseases and cancer, and why people suffering from depression die younger. At the same time, this research may help finding new therapeutic targets for the prevention and treatment of depression.
The original publication can be accessed here.