Depressive symptoms predict mucosal wound healing - Bosch et al, 2007 - Article

Summary with the article: Depressive symptoms predict mucosal wound healing - Bosch et al, 2007

Introduction

Lots of surgeries are performed each year. They come with risks, however. One of the possible risks is the development of depression, which can cause for instance longer hospital stays, more pain, increased use of analgesics. The negative affective states can increase physical symptoms, promote dysfunctional coping, but also slow down the process of wound healing. When wounds heal slower, the chances of developing infections are higher and the esthetic outcomes are poorer. A possible mediator of these effects is dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis.

The current study examined the relationship between loneliness, dysphoria and wound healing. Loneliness and dysphoria predict health outcomes. However, they are independent predictors of depression and so might have independent effects on wound healing. The present study focused on mucosal wound healing. The mucosa are very important in contact with the outside world and essential to life-supporting processes. Mucosal wounds heal faster and with less inflammation than skin wounds, and with minimal scarring. The study used healthy young adults with either high or low levels of loneliness or depressive symptoms. The hypothesis was that participants, who exhibit high levels of loneliness or dysphoria, have delayed healing of mucosal wounds. They also looked at a mediating role of diurnal cortisol secretion.

Results

Depressive symptoms, loneliness, dysphoria and wound healing

Approximately 50% of the participants wounds were healed seven days after the wounding. This was used as the criterion for fast and slow healers. A significant association was found between depressive symptoms and the time needed to heal. Dysphoric individuals were 3.5 times more likely to be slow healers than non-dysphoric individuals. High dysphoric individuals also showed larger wound sizes than low dysphoric individuals. Wound sizes were on average larger in the begin phases of repair in women than in men.

There was a robust association between dysphoria and wound healing and this association was not confounded or mediated by any demographic, anthropometric or health behaviour variable. These variables even strengthened the relationship between dysphoria and wound healing, indicating a suppressor effect. Low dysphoric participants drank more alcohol per week, and the high dysphoric participants reported fewer hours of sleep. High dysphoric participants also had more sleep disturbances. These variables were, however, not related to healing rate.

No mediation by cortisol

No association was seen between depressive symptoms and diurnal cortisol, also not after controlling for gender, BMI and smoking status. There was, however, a small negative association between BDI-sf (depression score_ and the average of all three morning levels. An association with delta morning-evening cortisol was also found, which indicates a flattened slope in participants with more depressive symptoms. Cortisol did not mediate in the association between dysphoria and wound healing. However, higher levels of loneliness were associated with less cortisol decline during the day and lower average morning cortisol levels.

Discussion

Higher depression scores were associated with slower healing. High dysphoric individuals had larger wound sizes, which indicates slower wound closure. They were 3.5 times more likely to be slow healers. So there is a strong association between psychological distress and wound healing. Demographic factors and health practices didn’t influence the association between dysphoria and wound healing.

For wounded tissue to heal quickly we need a trade-off between inflammation and rapid wound closure. Inflammation clears debris and infection, but can damage that delays the healing process. In mucosal wounds you want to have low inflammation and rapid healing. When inflammation is facilitated, the wound heals less quickly. In depression the inflammatory activity is upregulated, which might contribute to the delay in mucosal wound healing.

Glucocorticoids have been known to have a detrimental effect on wound healing. In this study, however, cortisol release was unrelated to mucosal wound healing. It suggests, that when in normal range, individual variations in circadian cortisol levels, have no major impact on the process of healing. However, this has to be researched further.

Depression can have negative effects on the autonomic nervous system and immune system. Dysregulation of the autonomic pathways might affect wound healing. Also activation of the parasympathetic nervous system regulates inflammation. Reduced parasympathetic activation might lead to local inflammation and thereby delay healing. Mucosa is densely innervated by parasympathetic nerves. Further research is warranted.

From the current study we can see that depression is a powerful predictor of physical health outcomes. Although loneliness and depressive symptoms are correlated, there was no association between wound healing and loneliness. There was for dysphoria, and therefore we see that dysphoria and loneliness are distinct features and they have different effects on health.

Limitations of the study were that participants with known risk factors for delayed healing were excluded from the study; the question of how depressive symptoms affects or interacts with other risk factors can’t be answered; the measurement of depressive symptoms wasn’t accompanied by clinical interviews; and it needs to be established to what extent the magnitude of the association between dysphoria and wound healing is preserved in samples not preselected on high and low depressive symptoms.

Important for the future is to educate the patient well before the surgery, because this reduces distress, leads to less analgesic use postoperatively and leads to better recovery. It might also be of help to identify and treat the depressed patient pre-surgically. This might also be cost effective.