A study comparing individuals with major depressive disorder to healthy controls found that those with depression exhibited higher cortisol levels after awakening than their healthy counterparts. This increase, however, was only observed in individuals with depression who had also experienced childhood trauma. The study was published in Psychological Medicine.
Cortisol is a steroid hormone produced by the adrenal glands. These glands are located on top of each kidney. Cortisol plays a vital role in the body’s response to stress. When a person experiences stress, cortisol levels increase. This increases blood sugar levels, suppresses the immune system, and aids in the metabolism of fats, proteins, and carbohydrates. However, prolonged or chronic elevation of cortisol levels can have adverse effects on health, including contributing to obesity, cardiovascular disease, and immune system dysfunction.
Cortisol is also one of the most promising biomarkers of major depressive disorder. Major depressive disorder is a mental health condition characterized by persistent and severe feelings of sadness, hopelessness, and a loss of interest or pleasure in most activities. Studies indicate that at least some individuals suffering from major depressive disorder have consistently elevated levels of cortisol in their blood.
Additionally, when these individuals are injected with dexamethasone, a synthetic analogue to cortisol, their cortisol levels do not decrease as much as they should. Elevated cortisol levels are also found in individuals who do not respond to psychotherapy i.e., in whom psychotherapy produces no or little improvement in symptoms.
The study’s lead author, Shabaz Sendi, and his team sought to determine if childhood trauma could alter the endocrine system’s function, which regulates cortisol in those with major depressive disorder. Drawing from prior research, they hypothesized that post-awakening cortisol levels would be highest in individuals with both major depressive disorder and childhood trauma and lowest in healthy individuals without any childhood trauma.
The study involved 43 healthy participants without any childhood trauma, 26 healthy participants with childhood trauma, 15 patients with major depressive disorder without childhood trauma, and 28 patients with both major depressive disorder and childhood trauma.
These participants underwent evaluations either in an inpatient clinic or at their homes. They completed depression assessments, specifically the Hamilton Depression Rating Scale (HAM-D 21), and a questionnaire determining the presence or absence of childhood trauma (Childhood Trauma Questionnaire, CTQ). Additionally, they provided five saliva samples to measure cortisol levels, with the first sample taken immediately upon waking and the subsequent four at 15-minute intervals.
The study found that demographic factors such as age, gender, and body mass index had no correlation with cortisol levels. The average waking time across the four groups was consistent.
Patients with major depressive disorder and a history of childhood trauma had higher baseline cortisol levels compared to healthy individuals both with and without childhood trauma. However, when the researchers controlled for sex of the participants, the only difference in cortisol levels that remained was between individuals suffering from major depressive disorder who also had a history of childhood trauma and the group of healthy individuals without childhood trauma.
“In summary, the present study showed that the total amount of cortisol released after awakening was increased in patients with major depressive disorder, although only when they had a history of childhood trauma,” the study authors concluded. “This finding resonates well with the notion that at least some neurobiological signatures of major depressive disorder may in fact be attributable to early life stress. They may also imply that this group of patients is characterized by yet to be determined (epi)genetic alterations, which render them non-resilient to childhood trauma.”
The study makes an important contribution to the scientific understanding of the links between early experiences and cortisol production in adulthood. However, it should be noted that the study sample was very small and that the study design does not allow any cause-and-effect inferences to be derived from the findings.
The study, “Childhood trauma associated with increased post-awakening cortisol in major depressive disorder”, was authored by Shabaz Sendi, Susanne Fischer, Andrew Papadopoulos, Lucia Poon, Lena J. Rane, Abebaw Fekadu, Valeria Mondelli, and Anthony J. Cleare.
