The concept of an "antidepressant" implies a drug that acts in a disease specific way to reverse the neuropathological basis of the symptoms of depression. However, there is little scientific research that could confirm this view. This paper reports an historical study of the emergence of the concept of the antidepressant and the social forces that influenced its adoption. Historical literature documents the increasing importance of the specificity of medical treatments in the 20th century and the increased power that they conferred on medical practitioners. In the case of depression, stimulants were used as treatment from the 1940s. During the 1950s the anti-tuberculous drugs iproniazid and isoniazid started to be portrayed as more specific than stimulants, even though their stimulant effects were well documented. When imipramine was suggested to be effective in depression, it was presented solely as acting in a disease specific way and it was soon referred to as an "antidepressant". The idea that some drugs have a specific action on the underlying basis of depression caught on rapidly and was well established by the 1960s before any evidence was available to support this view. Forces that could have driven the adoption of this view include the psychiatric profession's desire to integrate with general medicine to improve its social status and to move away from the asylum into the community. Physical interventions and drug treatments helped to boost its medical credentials and antidepressant drugs provided a convenient form of medical treatment for community-based distress. They also helped the profession to counter attacks from the antipsychiatry movement. The pharmaceutical industry too helped to establish and disseminate the view of antidepressants as disease specific treatments in order to distinguish them from non-specific drugs. This study raises questions about the view that psychiatry was transformed into a modern medical enterprise in the 1950s and 1960s by the introduction of disease specific drugs.