PS02 Illicit drug use in psoriasis and psoriatic arthritis and its relationship with suicidality in a tertiary population

Abstract Limited evidence suggests an increased lifetime prevalence of illicit drug use in psoriasis. To our knowledge, there are no data for psoriatic arthritis (PsA) in this regard. Given the pronounced psychiatric morbidity in psoriasis and PsA, including evidence of increased suicidality outcomes, we aimed to investigate illicit drug use prevalence and its relationship with disease characteristics and psychopathology in psoriasis. We surveyed 216 adults attending a specialist psoriasis service, 83 of whom had comorbid PsA. Participants completed paper questionnaires about the type, amount and frequency of lifetime and current illicit drug use (including cannabis, opioids, cocaine/stimulants, hallucinogens and volatile solvents). Participants also completed validated psychometric tools; suicidality was measured with the Sheehan Suicidality Tracking Scale. The prevalence of lifetime (21.7%) and current (6.0%) illicit drug use in PsA did not differ from the respective rates in psoriasis only (27.1% and 8.3%; P > 0.1), but patients with PsA showed lower regular use rates (2.7% in PsA vs. 12.9% in psoriasis only; P = 0.03). Dermatology Life Quality Index and Psoriasis Area and Severity Index scores were numerically higher among illicit drug users than nonusers, but the differences were not statistically significant. In our sample, lifetime illicit drug use was associated with increased lifetime suicidal planning and behaviour but not suicidal ideation. The association of drug use with suicidal planning remained after adjusting for age, sex, psychiatric comorbidity and alcohol consumption scores (odds ratio 2.44, 95% confidence interval 1.04–5.76). Patients reporting current drug use were more likely to have been previously diagnosed with anxiety but were not disproportionately affected by depression and alexithymia. The prevalence of lifetime illicit drug use in our study is consistent with findings from a recent North American psoriasis cohort. Although it is not clear why regular drug use is less prevalent in patients with PsA, increased medical attention may play a role. The higher prevalence of suicidal planning/behaviours, but not ideation, among patients with psoriasis with illicit drug use is an important and concerning finding. This aligns with some previous research suggesting that illicit drug use is associated with suicidality progression toward action, possibly due to impulse-control deficits. Early detection and management of drug use may help prevent suicidal behaviours in psoriasis. Study limitations include the cross-sectional design and social desirability bias-related under-reporting. Prospective cohorts are needed to further investigate the role of illicit drug use in patients’ psychiatric morbidity and quality of life, and address its sequelae within dermatology settings.