Mental health comorbidities associated with psoriasis

There is a high prevalence of mental health comorbidities in individuals with chronic psoriasis, including depression, anxiety, and suicidality. The causal relationship between the disease burden of psoriasis and mental health comorbidities is unclear, though studies suggest that there may be a link between psychosocial stress and exacerbation of psoriasis symptoms.¹

Here, we summarize key data from a study investigating the cause-effect relationships between psoriasis and mental health comorbidities.

Study design¹

• This was a bidirectional two-sample, Mendelian randomization (MR) study utilizing summary statistics from publicly available comprehensive genome-wide association studies of:
  • psoriasis (n = 306,123);
  • broad depression (n = 500,199);
  • major depressive disorder (n = 173,005);
  • anxiety (n = 17,310); and
  • suicide attempts (n = 50,264).

• Single nucleotide polymorphisms associated with exposure at a genome-wide significance of p < 5 × 10^-8, were selected for psoriasis, broad depression, and major depressive disorder, with the threshold for anxiety and suicide attempt being p < 5 × 10^-6.
• The random-effects inverse-variance weighted (IVW) model was used as the main analysis, along with several complementary statistical methods.
•  Significant evidence for association between disease burden and mental health comorbidities was regarded as associations with p < 0.00625.

Findings¹

The forward-direction MR analyses suggested that psoriasis was significantly associated with an increased risk of broad depression but only suggestively associated with risk of major depressive disorder (Figure 1).

IVW, inverse-variance weighted model; MR, Mendelian randomization; MR-PRESSO, MR-Pleiotropy residual sum and outlier; OR, odds ratio.
*Adapted from Chu, et al.¹

Psoriasis was found not to be significantly associated with the risk of anxiety or suicidality (Table 1).

Table 1. Association of psoriasis with the risk of anxiety in forward MR analysis*

MR, Mendelian randomization; IVW, effects inverse-variance weighted model; MR-PRESSO, MR-Pleiotropy residual sum and outlier. *Adapted from Chu, et al.1
Model	Odds ratio (anxiety)	p value (anxiety)	Odds ratio (suicidality)	p value (suicidality)
IVW	1.109	0.160	1.014	0.648
MR-PRESSO	1.109	0.178	1.014	0.654
Weighted median	1.106	0.221	1.015	0.721
MR Egger	1.430	0.080	1.011	0.845

The reverse-direction MR analyses suggested that psoriasis was significantly associated with an increased risk of broad depression and major depressive disorder (Figure 2).

MR, Mendelian randomization; IVW, effects inverse-variance weighted model; MR-PRESSO, MR-Pleiotropy residual sum and outlier; OR, odds ratio.
*Adapted from Chu, et al.¹ 

There was no evidence for a causal effect of anxiety or suicidality on an increased risk of psoriasis.

Conclusion¹

The results of this study suggest a causal link between psoriasis and the risk of depression and vice versa. This bidirectional relationship warrants further investigation. Screening for depression in patients with psoriasis, along with appropriate management, may lead to improved clinical outcomes.