Two hundred ten patients with anxiety and depressive disorders were followed up over 30 years. Personality status was assessed at baseline using the Personality Assessment Schedule (PAS), an instrument that classifies personality disorder in a similar way to the new ICD-11 classification. Assessments of suicidal behaviour were made at 5, 12 and 30 years and suicidal thoughts at 12 and 30 years and analysed by personality status, clinical diagnosis and scores on the General Neurotic Syndrome Scale, a combined diagnosis of mixed anxiety depression and personality dysfunction. Suicide attempts were most frequent in the first 5 years of the study and reduced over time. Baseline personality status was the best predictor of suicide attempts at 5 years (no personality disorder 29.3%, personality disorder 51.6%, p = 0.006), and at 12 years (no personality disorder 11.9%, personality disorder 25.7%, p = 0.042), but no important differences were found at 30 years, when comorbid mental state disorder was the strongest predictor (p < 0.001). Similar but less marked findings were found for the general neurotic syndrome. It is concluded that the presence of personality disorder is a robust predictor of suicidal behaviour in the shorter term but in the long-term comorbid pathology is a better predictor.