Are Patients with Psoriasis at Risk for Depression?
There is growing interest in and research of how the body affects the mind and vice versa. This is particularly true in the area of inflammatory diseases such as psoriasis. Research has shown that psoriasis is associated with significant mental illness comorbidities like anxiety and depression. But how exactly do psoriasis and mental health conditions interplay?
“Studies focusing on a diagnosis of major depressive disorder (MDD) find that 15 to 20 percent of patients with psoriasis are at risk for major depression, compared to 7 to 10 percent within the general population and/or without psoriasis. However, when we start talking about patients who have symptoms but do not meet MDD criteria, we find that a large proportion may have some symptoms of depression or other mental health issues,” says Dr. Tina Bhutani, M.D., MAS, who is assistant professor at the University of California San Francisco. Diagnostic criteria for MDD include but are not limited to depressed/irritable mood, anhedonia, sleep disturbance, fatigue, and suicidal ideation. To be diagnosed with MDD, a certain number of symptoms must present during the same timeframe, but one could see how patients with psoriasis may experience many of those same symptoms without meeting the full criteria.
Is Depression a Systemic Disease?
“I think depression is a systemic disease, however, this is a contemporary viewpoint on mood disorders,” says Dr. Bhutani. “Depression symptoms go beyond depressed mood, including changes in appetite, sleep, pain, fatigue, and so on, leading me to think depression is probably a systemic illness. Depression causes changes in the immune system, including different levels of antioxidants and biomarkers. Evidence is starting to prove that point. In fact, studies have shown the impact of IL17.”
An example of the interleukin (IL)-17 research Dr. Bhutani mentioned is published in Basic and Clinical Neuroscience, which demonstrated elevated serum IL-17 and transforming growth factor B levels in patients with MDD. This research supports the association between inflammatory response and depressive disorder. 
Furthermore, research was published in the International Journal of Rheumatic Diseases, which demonstrated elevated serum IL-17 in patients with rheumatoid arthritis (RA). These IL-17 levels were “significantly higher” in patients with RA and anxiety than those without anxiety. Data also showed that patients with RA had higher levels of tumor necrosis factor (TNF)-a and IL-6 as well. 
But it’s not just RA.
Research findings published in Skin Pharmacology and Physiology showed a significant link was found between depression and psoriasis, primarily through immune mechanisms related but not limited to the actions of inflammatory cytokines such as TNF-a, IL-1, IL-2, IL-10, interferon-γ, IL-1β, prostaglandin E2, C-reactive protein, IL-6 and IL-8. 
Additionally, according to findings from a meta-analysis published in the Journal of Clinical Psychiatry, “depression was associated with higher oxidative stress MDA levels, lower antioxidant uric acid and zinc levels, and higher antioxidant-enhancing enzyme SOD levels, while differences in total nitrites and CAT and GPX were nonsignificant.” However, researchers found that antidepressant treatment reduced malondialdehyde (MDA), and increased uric acid and zinc levels. These levels were unchanged in healthy controls. 
The Effects of Sleep (or a Lack Thereof)
The Centers for Disease Control recommends adults between the ages of 18 and 60 sleep at least seven hours every night. However, data from a 2014 Behavior Risk Factor Surveillance System found that more than one-third of adults reported insufficient sleep.  “We don’t respect sleep. We don’t value sleep. Lack of sleep can put us at increased risk of diabetes, CV, depression, which is similar to the risks we see with psoriasis,” says Dr. Bhutani. “Sleep affects our mental health 100 percent.”
Short sleep duration, or sleeping less than 7 hours per night, is associated with greater likelihoods of obesity, high blood pressure, diabetes, coronary heart disease, stroke, frequent mental distress and death. 
Dr. Bhutani has had first-hand experience witnessing the power of sleep. “This research has been very interesting,” she says. “My interest in sleep and psoriasis was triggered by a patient with stubborn palmoplantar psoriasis. He was a guitarist, and the plaques on his palms were affecting his playing. Once his sleep improved, so did his palmoplantar psoriasis. The old teaching was that poor sleep was an outcome of mood disorder, where new, more contemporary teaching is showing that sleep is both a consequence and cause of mood disorders.”
The connection between mind and body and how that may be related to psoriasis flares, mental stress and disease worsening is an area of growing research and increasing importance. “We know sleep can affect the immune system,” says Dr. Bhutani. Research has shown that sleep deprivation can lead to increased levels of inflammatory cytokines, such as IL-1, IL-6, TNF-a, and C-reactive protein. These increases can lead to further activation of the inflammatory cascade.  “Studies in patients with rheumatoid arthritis and irritable bowel disease who experience sleep disturbance have shown cytokines increases, including TNF alpha and IL1. In a study in mice with psoriasis, sleep-deprived mice had increased inflammatory cytokines,” says Dr. Bhutani, who is in the process of designing a study to look further into sleep and psoriasis.
Health care providers may be the first to recognize patients' changes in mental status. “It is really important to remember that psoriasis patients are at higher risk for mood disorders, anxiety, Seasonal Affective Disorder, depression and suicidal ideation, among others. We [health care providers] have longitudinal relationships with patients, so we may notice differences and can ask questions. It’s important to ask a patient how their mood has been or how have they been doing. Open-ended questions can open the flood gates,” says Dr. Bhutani. She also adds that validated mental health questionnaires exist but suggests not getting too caught up in those.
Health care providers may also want to inquire about patients’ sleep. Dr. Bhutani recommends asking about sleep quantity and quality. “It’s important to ask if patients are waking up multiple times or having trouble falling asleep. Health care providers can dig into what may be causing sleep disturbances, which may lead to the discovery of an undiagnosed issue, such as sleep apnea or anxiety.”
Dr. Bhutani also recommends health care providers discuss good sleep hygiene with their patients, including “no screens before bed, no working in bed and use of white noise." According to the American Alliance for Healthy Sleep, good sleep hygiene is a series of healthy sleep habits that may improve a person's ability to not only fall asleep but stay asleep. They are also the “cornerstone” of cognitive-behavioral therapy. Sleep tips from the AAHS include: 
- Keep a consistent sleep schedule. Get up at the same time every day, even on weekends or during vacations.
- Set a bedtime that is early enough for you to get at least seven hours of sleep.
- Don’t go to bed unless you are sleepy.
- If you don’t fall asleep after 20 minutes, get out of bed.
- Establish a relaxing bedtime routine.
- Use your bed only for sleep and sex.
- Make your bedroom quiet and relaxing. Keep the room at a comfortable, cool temperature.
- Limit exposure to bright light in the evenings.
- Turn off electronic devices at least 30 minutes before bedtime.
- Don’t eat a large meal before bedtime. If you are hungry at night, eat a light, healthy snack.
- Exercise regularly and maintain a healthy diet.
- Avoid consuming caffeine in the late afternoon or evening.
- Avoid consuming alcohol before bedtime.
- Reduce your fluid intake before bedtime.
Increasingly, the impact of mental health on a patient’s quality of life is being recognized by both health care providers and patients alike. Research highlighted in the Joint AAD-NPF Guidelines of Care for the Management and Treatment of Psoriasis with Awareness and Attention to Comorbidities found that patients with psoriasis were at least 1.5 times more likely to have depression, compared to a control group. Beyond this study, the guidelines found that studies on mental health and depression “strongly suggest that when skin disease improves, patients have a concurrent improvement in their psychiatric symptoms.” 
NPF has also charged researchers to further investigate the impact psoriatic disease has on mental health and potential interventions to improve the well-being of our patient community. The More Than Skin Deep: Mental Health funding opportunity will provide $100,000 to innovative projects focused on this comorbidity.
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2. Liu Y, Ho RC, Mak A. The role of interleukin (IL)-17 in anxiety and depression of patients with rheumatoid arthritis. Int J Rheum Dis. 2012;15(2):183-187. doi:10.1111/j.1756-185X.2011.01673.x
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4. Jiménez-Fernández S, Gurpegui M, Díaz-Atienza F, Pérez-Costillas L, Gerstenberg M, Correll CU. Oxidative stress and antioxidant parameters in patients with major depressive disorder compared to healthy controls before and after antidepressant treatment: results from a meta-analysis. J Clin Psychiatry. 2015;76(12):1658-1667. doi:10.4088/JCP.14r09179
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7. Healthy Sleep Habits. Sleep Education. http://sleepeducation.org/essentials-in-sleep/healthy-sleep-habits. Published February 9, 2017. Accessed January 11, 2021.
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