Psoriasis is associated with poor mental health and reduced quality of life. Although the high risk for depression in patients with psoriasis is well-established, their suicidality risk is uncertain. Previous studies provide contrasting results and have not included patients with clinically-confirmed severe disease. Our aim was to determine risk of suicide among patients with moderate to severe psoriasis compared with the general population, and investigate if psychiatric comorbidity or history of suicidality increases future suicidality risk in psoriasis. We further estimated the incidence of suicidal and self-injurious behaviours in patients. Analysis was performed using the British Association of Dermatologists Biologics and Immunomodulators Register (BADBIR). As controls, general population mortality and suicide data were used. There were 9 suicides in BADBIR. The incidence rate of suicide was 12.5 per 100,000 person-years (95% CI 6.53, 24.11) in BADBIR versus 11.0 per 100,000 person-years (95% CI 10.7, 11.3) in the general population in England and Wales. Among patients, psychiatric comorbidity or past suicidality was associated with higher risk for suicidal ideation, suicide attempts and self-injurious behaviours. Suicide rates among patients with moderate to severe psoriasis were not significantly higher compared with the general population. Suicide is a rare event and our results are limited by the uncertainty in the estimate reliability. However, considering the high depression prevalence in psoriasis, our findings support the need for prompt assessment of patients for psychiatric comorbidities and suicidality history. Further research is required on suicidal behaviours and the role of psoriasis severity.