National report - Chronic stress plus exposure to UVB radiation substantially increases the susceptibility to squamous cell carcinoma; the chronic stress also suppresses the production of immunological molecules, such as gamma interferon, according to the study's author, Firdaus Dhabhar, Ph.D.
"Interestingly, chronic stress increased (the) number of suppressor cells that may inhibit anti-tumor immune responses," Dr. Dhabhar, associate professor and neuroimmunologist at Stanford University, says.
After monitoring for eight months, stressed mice had a shorter median time in developing the first tumor (15 weeks versus 16.5 weeks) and reached a 50 percent incidence six weeks earlier than did the nonstressed mice (Dhabhar, Lemeshow, et al. J Natl Cancer Inst. 2005; 97:1760-1767).
Strengthening stress, disease link
With previous studies supporting the link between stress and skin disease, most notably the recent work of Francisco Tausk, M.D. - which used fox urine to induce stress in mice to show heightened skin tumor development through light exposure (J Am Acad Dermatol. 2004;51:919-922) - this latest evidence further magnifies the stress-skin disease quagmire.
"Other disciplines have made anecdotal observations that increased stress may lead to tumor development due to its immunosuppressant effects," says Alexa Boer Kimball, M.D., Ph.D. "And, the popularity of our study around the world was a clear message to me that the experience of stress and those who experience acne is universal, which is why it resonated with so many people."
Attempting to debunk the theory that stress causes acne vulgaris to worsen, Dr. Kimball's study instead found a strong correlation between not just the worsening of acne due to stress, but also of the magnitude of stress with the acne it caused (Arch Dermatol. 2003;139:897-900).