Depression is a serious health problem, not just the everyday ups and downs. It is quite complex, and symptoms may vary from person to person. Although there are common symptoms, not in each time that the proven checklist is enough to consider if a person suffers from extreme depression.
The bible of psychiatry, which they called the Diagnostic and Statistical Manual of Mental Disorders (DSM), contains a list of symptoms that may help diagnose depression in a suspected patient. Psychiatrists usually record the number of symptoms that patients report in questionnaires and check if these match with a number of symptoms listed in the manual. Such a diagnostic procedure does not give attention to the type of symptoms that the patient manifest but instead to the number of how many of these signs are in the checklist.
However, a large-scale quantitative study challenges this diagnostic approach. Their findings suggest that the symptoms are not equivalent, with one playing a much bigger role than others in driving depression. It also shows that the ones listed in the DSM may not be the symptoms useful in diagnosing depression.
"We need to stop thinking of depression as a disease that causes a number of interchangeable symptoms," says principal author Dr. Eiko Fried from the KU Leuven Faculty of Psychology and Educational Sciences, in a press release. "Depression is a complex, extremely heterogeneous system of interacting symptoms. And some of these symptoms may be far more important than others."
Researchers investigated a total of 3463 depressed patients and examined the connection among the symptoms they reported. With their network analysis of the 28 symptoms, they found that some are more 'central' - more connected - than others, suggesting that these symptoms have far bigger impact in steering depression.
Another finding also showed that the two main DSM symptoms - sad mood and decreased interest - ranked among the top five in terms of importance. On the other hand, hypersomnia, agitation and weight change were found to be the ones least 'central'.
"Ideally, the list of depression symptoms should become more comprehensive to do justice to the heterogeneity of depression. I also think both clinicians and researchers can learn a lot from paying more attention to individual symptoms and their interactions," says Dr. Fried.
"But of course, we need much more research before we can actually replace the DSM diagnosis of depression with something else," Dr. Fried adds.
The study appears in Journal of Affective Disorders.