Concerns have been raised that prolonged exposure to heavy metal music with aggressive themes can increase the risk of aggression, anger, antisocial behaviour, substance use, suicidal ideation, anxiety and depression in community and psychiatric populations. Although research often relies on correlational evidence for which causal inferences are not possible, it is often claimed that music with aggressive themes can cause psychological and behavioural problems. This narrative review of theory and evidence suggests the issues are more complicated, and that fans typically derive a range of emotional and social benefits from listening to heavy metal music, including improved mood, identity formation, and peer affiliation. In contrast, non-fans of heavy metal music — who are often used as participants in experimental research on this topic — invariably report negative psychological experiences. Our review considers a comprehensive set of empirical findings that inform clinical strategies designed to identify fans for whom heavy metal music may confer psychological and behavioural risks, and those for whom this music may confer psychosocial benefits.