We performed a cross-sectional, questionnaire-based study to explore the relationship of suicidal ideation, mental health problems, and social functioning to acne severity among adolescents aged 18-19 years. A total of 4,744 youth were invited and 3,775 (80%) participated. In all, 14% reported having substantial acne (a lot and very much). Among those with very much acne, as compared those with no/little acne, suicidal ideation was twice as frequently reported among girls (25.5 vs. 11.9%) and three times more frequently reported among boys (22.6 vs. 6.3%). Suicidal ideation remained significantly associated with substantial acne (odds ratio 1.80, 95% confidence interval 1.30-2.50) in a multivariate model including adjustments of symptoms of depression, ethnicity, and family income. Mental health problems, as assessed by the Strengths and Difficulties Questionnaire (2.25, 1.69-3.00), low attachment to friends (1.52, 1.21-1.91), not thriving at school (1.41, 1.12-1.78), never having had a romantic relationship (1.35, 1.05-1.70), and never having had sexual intercourse (1.51, 1.21-1.89) were all associated with substantial acne in a multivariate model. Acne is frequently found in late adolescence and is associated with social and psychological problems. Adverse events including suicidal ideation and depression that have been associated with therapies for acne may reflect the burden of substantial acne rather than the effects of medication.