Patients with psoriasis have a higher risk of developing depression or anxiety, and having suicidal feelings, says a report published today in Archives of Dermatology, a JAMA/Archives (Journal of the American Medical Association) journal. Psoriasis is a dry, scaly skin disorder. Doctors believe that it is genetic and is caused by the immune system being mistakenly "triggered", resulting in skin cells being produced too quickly.

The authors state that approximately 1% to 3% of the general population is affected with psoriasis - of which a significant number have not been diagnosed (possibly between 0.4% and 2.3% of the adult population with the condition).

The authors wrote:

Psoriasis has long been recognized to be associated with potentially adverse effects on mental health. In the 1960s, a popular ad campaign labeled the emotional burden of this skin disease as the 'heartbreak of psoriasis.' However, there have been relatively few studies evaluating psychological outcomes in patients with psoriasis.

Shanu Kohli Kurd, M.D., M.S.C.E, M.H.S., and team at the University of Pennsylvania, Philadelphia, examined data from electronic medical records in the UK from 1987 to 2002, involving:
  • 146,042 patients with mild psoriasis
  • 3,956 patients with severe psoriasis
  • 766,950 patients without psoriasis (5 control patients for each patient with psoriasis, selected from the same practice and similar entry dates)
Patients were defined as having new-onset depression, anxiety or suicidal feelings (suicidality) if corresponding diagnostic codes appeared in their records after follow-up began.

The study revealed that, of the patients with mild or severe psoriasis:
  • 25.9 per 1,000 people per year were diagnosed with depression
  • 20.9 per 1,000 per year with anxiety
  • 0.9 per 1,000 per year with suicidal feelings
Of these, the rate attributable to psoriasis was:
  • 11.8 per 1,000 people per year for depression
  • 8.1 per 1,000 per year for anxiety
  • 0.4 per 1,000 per year for suicidal feelings
The authors wrote:

Stated another way, the excess risk attributable to psoriasis is one case of depression for every 39 patients with severe psoriasis per year (or per 87 patients in patients with mild psoriasis per year).

The excess risks associated with psoriasis for anxiety and suicidality correspond to one case per 123 and 2,500 patients with psoriasis per year, respectively." Considering this data and the prevalence of psoriasis in the U.K., the authors estimate that there are more than 10,400 diagnoses of depression, 7,100 of anxiety and 350 of suicidality related to psoriasis each year.

(conclusion) It is important to identify these psychiatric disorders because they represent substantial morbidity that can be improved with a variety of pharmacological and non-pharmacological approaches.

Recent data suggest that psychiatric co-morbidity may negative affect response to certain psoriasis treatments (e.g., photochemotherapy), while other studies suggest that control of psoriasis is associated with improvements in psychological symptoms. Future studies are necessary to determine the mechanisms by which psoriasis is associated with depression, anxiety and suicidality as well as approaches to prevent such adverse outcomes in patients with psoriasis.

Arch Dermatol
Published August. 2010;146[8]:891-895.

Written by Christian Nordqvist