A new study showing that depression may be closely related not only to mood but also to the sleep-wake cycle has brought a subtype called “circadian depression” to the fore. According to research by scientists at the University of Sydney, this profile can be seen in approximately one-quarter of people experiencing severe, recurrent, or long-term depression.
The study examined the link between symptoms of depression and the body's approximately 24-hour biological rhythm. The circadian rhythm affects many functions, from sleep hours to hormone secretion, and from body temperature to metabolic regulation. It is considered that disruptions in this rhythm may not only be a result of depression in some individuals but also a factor playing a role in the persistence of the condition.
PROMINENT SYMPTOMS IN CIRCADIAN DEPRESSION
The study focused on six characteristics associated with circadian depression. Participants who exhibited at least three of these characteristics were evaluated within the circadian depression group for the purposes of the research.
- - Waking up tired in the morning and not feeling rested even after getting enough sleep.
- - A tendency to stay awake until late at night and go to sleep late.
- - Sleeping more than usual during depressive episodes.
- - Mood being affected by seasonal changes and daylight.
- - A significant difference in sleep hours between work or school days and holidays.
- - Feeling more energetic during the evening and night hours.
The research, conducted within the Brain and Mind Centre at the University of Sydney, examined the clinical and genetic data of more than 10 thousand Australians. The scientific article published in The British Journal of Psychiatry included data from 11 thousand 380 participants.
According to the findings, 2 thousand 604 people, or approximately 23 percent of the participants, exhibited characteristics of circadian depression. The rate pointed out by the researchers applies to the group studied who were experiencing severe, recurrent, or long-term depression. Therefore, the results do not mean that one in every four people in the general population experiences depression or has this subtype.
WHY IS IT IMPORTANT IN TERMS OF TREATMENT RESPONSE?
One of the notable findings of the study was that participants showing characteristics of circadian depression reported lower responses to some common antidepressants. The study stated that the response to SSRI and SNRI class drugs, in particular, might be more limited in this group, and that reports of side effects were higher.
The researchers suggest that approaches targeting the biological clock could be important for these individuals. Light therapy, restructuring of sleep patterns, and treatment options related to the melatonin system are among the topics discussed in this context.
However, for experts, these findings do not mean that these methods are suitable for everyone or that they will provide treatment on their own. Depression treatment must be planned individually and with physician evaluation.
Circadian depression is not currently a globally accepted independent psychiatric diagnostic category. The study is significant in that it opens a new field for research aimed at better distinguishing subtypes of depression and personalizing treatment approaches. The researchers state that the findings need to be replicated in different populations and that biological mechanisms need to be examined in more detail.
News Source: 12punto
