Patients aged 18–65 years with newly diagnosed diabetes mellitus (n = 89) or rheumatoid arthritis (n = 100) were studied by the General Coping Questionnaire at baseline and after 24 months. In total, 34 diabetes mellitus and 46 rheumatoid arthritis patients were diagnosed with psychosocial problems. The use of negative coping strategies, such as protest, isolation, and intrusion, was associated mostly with being classified as having psychosocial problems. With the risk of experiencing a strong impact of the disease at 2 years of follow-up as outcome, intrusion was a significant and independent risk factor, while minimization was a significant and independent protective factor.