The physiological “stress response” likely evolved to deal with acute stressors (usually short-term, life-threatening stressors) by mobilizing energy for immediate use and suppressing nonessential systems.17
Although the stress response is well-adapted to deal with acute stressors, chronic activation of the system—as is often the case for those with poor living conditions and psychological stressors—results in poor psychological and physical health outcomes.18
Several biological systems are activated by stress, but we focus on the HPA axis and the implications this system has for negative health behaviors that may buffer the effects of stress on mental disorders.
When an organism experiences stress, the HPA axis response begins with the release of corticotropin-releasing factor (CRF) from the hypothalamus, stimulating the release of adrenocorticotropic hormone (ACTH) from the pituitary gland. ACTH travels through the bloodstream to stimulate the release of cortisol from the adrenal cortex. Via a negative feedback loop, cortisol then acts on the hypothalamus and pituitary gland to shut down the release of both CRF and ACTH.
Recent research from Dallman et al.19,20
suggests that consumption of foods that are high in fats and carbohydrates reduces anxiety via feedback to the HPA axis. During chronic stress, the negative feedback loop through which cortisol regulates further release of CRF breaks down as glucocorticoid receptors are downregulated and the release of CRF continues. Continued release of CRF is associated with feelings of anxiety as CRF mRNA expression in the amygdala is increased20
; consuming comfort foods aids in the “shutdown” of the stress response by regulating the release of CRF. Abdominal fat deposits resulting from comfort food consumption signal increased metabolic energy stores, which in turn decrease the expression of CRF mRNA in the hypothalamus via the inhibition of catecholamine production in the nucleus of the tractus solitarius. Put more succinctly, eating comfort food reduces anxiety by inhibiting the release of CRF.19,20
High rates of obesity are observed in Black populations, particularly among women,21
and it is believed that consuming large amounts of comfort foods may contribute to this condition. Consuming comfort foods may be a socially accepted, gender-appropriate way of dealing with chronic stress among this population.3
Also, sources of comfort foods may be more prominent in poorer and Black communities because of the proliferation of fast-food outlets and convenience stores in these areas. However, this stress-reduction technique imposes a cost. Chronic activation of the HPA axis has been linked to type II diabetes via promotion of insulin resistance in fat cells. In addition, consumption of high-fat, high-carbohydrate foods is related to stroke, cardiovascular disease, and other disorders.
Alcohol intake is believed to reduce anxiety and relieve tension.22
Human studies reveal that there is a positive relationship between stress levels and negative psychological states on the one hand and alcohol consumption on the other.23,24
We believe that alcohol’s simultaneous elevation of dopamine and β-endorphin levels in the brain results in a feeling of relaxation and subjective release from stress.25
Thus, alcohol consumption activates the HPA axis, increases release of dopamine and β-endorphins, and likely reduces feelings of stress.26
Smoking and nicotine ingestion are often reported to result in mild euphoria, increased energy, suppressed appetite, and a sense of well-being.27
Nicotine is thought to reduce stress-related anxiety,28
and researchers have focused on how the HPA axis is affected by tobacco use. Research in both humans and animals has found evidence that nicotine increases levels of stress hormones,29,30
suggesting that nicotine has an anxiogenic effect. Nicotine has other neurologic effects, however, that may explain the anxiolytic effects reported by individuals who use tobacco. Paradoxically, the release of stress hormones in response to nicotine actually mediates the response of the mesolimbic dopamine system, giving rise to feelings of relaxation, reduced anxiety, and calm.31
The same pattern of physiological responses is also found following the use of illegal stimulants.32
In addition, these drugs also activate the HPA axis, which may increase the allostatic load of the individual.18
Thus, although individuals may be protected from the psychological effects of stress, they are not protected from its physical effects.