Are you feeling depressed? Are you feeling fatigued? Are you feeling depressed and fatigued? Do you start feeling depressed, then start to feel fatigued? Do you feel fatigued for a week, then begin to feel depressed? Well, you are not alone. A 2004 study by lead author Petros Skapinakis, MD, MHD, Ph. D, revealed a strong correlation between fatigue and depression. This followed up a 2000 study by Skapinakis, published in the American Journal of Psychiatry, that also showed a correlation between fatigue and depression.
The 2004 longitudinal study followed 3,201 subjects from 14 different countries for 12 months. The objective was to clarify the relationship between depression and unexplained chronic fatigue. The results showed a very strong correlation: the chronically depressed subjects were more than 4 times as likely to suffer from unexplained chronic fatigue. The subjects suffering through unexplained, chronic fatigue were almost 3 times as likely to contract a new episode of depression. The results clearly show that depression, in addition to depressing your mood, will bring down your energy level as well.
The 2000 study examined census data from 12,730 subjects in Great Britain. The analysis showed that individuals suffering from psychiatric morbidity had higher rates of unexplained chronic fatigue. These two studies prove a strong correlation, but they also provide room for further speculation. Are fatigue and depression two symptoms of the same physical or mental problem? Or does one cause the other? An intuitive story can easily be drawn to explain the cause-and-effect relationship-man becomes depressed, battles all day with mental conflict, loses motivation, is tired and sluggish since 'not doing anything' (in reality he is using his energy in mental wars all day and night). The story could also work in reverse-man is tired day after day, for no apparent reason. He can not perform as well at work or in his personal life, and therefore he becomes depressed. This relationship is obvious and clear.
However, the studies prove this causality themselves. The possibility still remains that this fatigue and depression are both actually caused by a third phenomenon. This third, independent factor could be chemical, mental, or even an external, socioeconomic factor.
I personally subscribe to the cause-and-effect model, but would be interested to see the results of further studies. The debilitating spiral of depression and fatigue is very difficult to overcome. It could be a boon to the afflicted to pinpoint an independent outside cause of their depression and fatigue. This factor could be addressed and corrected, thereby alleviating the depression and fatigue. One can only hope for more research and improvements in the science of this mental health struggle.