Psoriasis, is an inflammatory chronic skin disease which has a heavy physical and psychosocial impact on participant's life. This is a study to finalize and validate a questionnaire to assess the long-term effect of long-term psoriasis in adult participants.

Approximately 550 adult participants with moderate to severe plaque psoriasis will be enrolled in approximately 15 dermatology centers in Italy.

Participants will receive standard of care while participating in this study. No drug will be administered as a part of this study. The duration of this study is up to 22 months.

There is no additional burden for participants in this study. Participants will attend regular visits during the course of the study at a hospital or clinic.

Inclusion Criteria:

• Participants with a diagnosis of moderate-to-severe plaque psoriasis (PASI≥10 or PASI<10 with involvement of sensitive areas) since at least 10 years.
• Adult partner in relationship with the participant since at least 3 years(Part 2 only).

Exclusion Criteria:

- Participants with psychiatric conditions.

Adult participants with moderate-to-severe psoriasis