The natural course of elevated depressive symptoms or subthreshold depression in patients with an acute coronary syndrome (ACS) is presented, as is the prognostic impact. Safe and effective psychological treatment options are desirable for subthreshold depression in patients with ACS, should they prove tolerable, efficacious, and cost-effective to cardiologists and their patients. To achieve this long-term goal, we propose focusing on 3 intermediate goals. First, we need to understand which symptoms or patterns of symptoms (eg, fatigue, anhedonia, guilt feelings) are specifically predictive of ACS recurrence. Second, the prevalence of known psychosocial vulnerabilities (proximal causes) of depressive disorders should be assessed in patients with ACS, to understand better the etiology of these symptoms in these patients. Third, randomized controlled trials of vulnerability-related, evidence-based psychological depression interventions in cardiac patients are needed. The ways in which psychological proximal cause theories are relevant--or irrelevant--for both the treatment of depressive symptoms in post-ACS patients and the prevention of ACS recurrence are discussed.