Role of serendipity in the discovery of classical antidepressant drugs: Applying operational criteria and patterns of discovery

Figure 1 Diagram of the four patterns of serendipitous attribution in the discovery of pharmacological agents. ¹They usually, but not always, relate to findings in laboratory animals; ²Findings relating to clinical efficacy.

Figure 2 Historical process of the discovery of tricyclic antidepressants during the 1950s. TCAs: Tricyclic antidepressants.

Figure 3 Historical process of the discovery of monoamine oxidase inhibitors during the 1950s. APA: American Psychiatric Association; MAOI: Monoamine oxidase inhibitors.