In recent years, psychiatry in Iran witnessed a dramatic increase in the use of the diagnosis of bipolar spectrum disorder (BSD). This qualitative study maps the journey of the BSD diagnosis from the West to Iran, examines the controversy surrounding the diagnosis and its treatment, and explores some of the structural factors that facilitate and maintain the widespread use of the BSD diagnosis in Iran and related practices of prescribing neuroleptic and mood stabilizers. The study methods include archival research and semi-structured interviews with 25 prominent Iranian psychiatrists in the field of mood disorders. Results show the importance of factors in addition to economics in driving changes in diagnostic fashion. Most psychiatrists interviewed reported what they viewed as an over-diagnosis of bipolar disorder and over-prescription of mood stabilizers and atypical antipsychotics among Iranian psychiatrists over the past decade. In addition to the influence of leading figures of American psychiatry, the dominance of Western psychiatric classifications and textbooks in Iran's psychiatry, and indirect intervention by pharmaceutical companies, local structural and political factors have played a significant role in the Iranian psychiatric system's embrace of the new concept of bipolarity. In Iran, the medicalization of social conflict has been embraced by government, families, and psychiatrists for cross-cutting purposes. These challenges and the continued controversy over the adoption of American psychiatric fads in a non-Western country like Iran point to the importance of elaborating a more ecosocial and cultural view of psychiatric practice to disentangle some of the complex trade-offs involved in adopting particular modes of diagnostic practice.