Obsessive-Compulsive Disorder (OCD) is a mental health condition defined by obsessions—recurrent, intrusive thoughts or images—and compulsions—repetitive behaviors or mental acts performed to reduce distress. These patterns of thought and action consume significant time and interfere with daily functioning. The understanding of OCD is a long, evolving story that moved from religious interpretation to formal medical classification over centuries, culminating in modern diagnostic standards. Recognizing OCD as a distinct disorder involved several thinkers and clinicians who progressively refined the definition of these symptoms.
Early Descriptions of Intrusive Thoughts
Long before psychiatric labels existed, the characteristic symptoms of OCD were recognized and explained through a moral or spiritual lens. These symptoms were often described as scrupulosity, a term used as early as the 14th century to denote an excessive preoccupation with religious or moral purity. This fixation on the fear of sinning led to compulsive behaviors like excessive praying, repetitive confessions, or seeking constant religious reassurance.
In the 15th century, figures such as Antoninus of Florence described the “scrupulous conscience” as a state tormented by baseless fears of failing to act according to God’s will. Intrusive thoughts were often viewed as temptations from the devil or a form of spiritual affliction. For example, the Bishop of Norwich, John Moore, described in the 17th century how worshippers were plagued by “blasphemous thoughts” during prayer. This historical view framed the experience as a moral or spiritual failing rather than a medical condition, delaying its formal classification.
Formalizing the Diagnosis in the 19th Century
The 19th century marked a significant shift, as psychiatrists began classifying these symptoms as a distinct medical disorder, moving away from moral and religious explanations. The French psychiatrist Benedict Augustin Morel contributed to this early classification, placing the condition within a broader category he termed “delire emotif” or “diseases of the emotions.” Morel believed that emotional distress and obsessions stemmed from a pathology affecting the autonomic nervous system, separating the condition from general insanity.
A major step toward modern understanding came in 1877 when the German neuropsychiatrist Karl Westphal provided the first precise medical definition. Westphal coined the term “Zwangsvorstellung,” or “obsessional idea,” to describe the core intrusive thoughts. He recognized the condition as an independent entity, distinct from other forms of mental illness like melancholia. Westphal is often credited with formally naming the disorder, providing the conceptual foundation for the term “obsession.”
Later, the French physician Pierre Janet further refined the clinical description in his 1903 work, Obsessions and Psychasthenia. Janet categorized the condition as Psychasthenia, a “lowering of psychological tension” resulting in a deficit of mental energy. He offered detailed clinical descriptions of the symptoms, including the need for precision, order, and the sense of incompleteness, focusing on components like doubt and indecision.
The Psychoanalytic Interpretation
Following early medical classifications, Sigmund Freud introduced a highly influential theoretical model that dominated the understanding of the disorder for much of the 20th century. Freud renamed the condition “Obsessional Neurosis,” theorizing it was rooted in unconscious conflicts arising from psychosexual development. He proposed that symptoms were a defense mechanism against unacceptable aggressive or sexual impulses originating from the anal-sadistic stage.
This stage, typically occurring between 18 months and three years of age, involves the child’s struggle with control related to toilet training. Freud suggested that fixation at this stage could lead to the “anal character” in adulthood, marked by traits like excessive orderliness and obstinacy. The intrusive thoughts and compulsive actions were viewed as symbolic expressions and attempts to “undo” these underlying, repressed impulses.
The psychoanalytic model shaped treatment by focusing on resolving these deep-seated, unconscious conflicts. Although this interpretation has since been largely superseded by neurobiological and cognitive models, it established the disorder as a psychological rather than a purely neurological problem. It was the prevailing framework until the late 20th century, influencing how clinicians perceived the relationship between thoughts and actions.
Establishing Modern Diagnostic Criteria
The final stage in the condition’s recognition involved its standardization within formal psychiatric classification manuals. For decades, the disorder was broadly grouped with other anxiety-related conditions. This classification began to shift with the publication of the third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III) in 1980, which officially listed Obsessive-Compulsive Disorder as a distinct anxiety disorder.
This formal inclusion ensured the disorder was recognized with specific diagnostic criteria, facilitating research and targeted treatment. The criteria required that obsessions or compulsions be time-consuming, typically taking more than one hour per day, or cause significant distress and impairment. The most definitive change occurred with the release of the DSM-5 in 2013, which moved OCD out of the anxiety disorders section entirely.
In the DSM-5, OCD was given its own dedicated chapter, “Obsessive-Compulsive and Related Disorders,” alongside conditions like Body Dysmorphic Disorder and Hoarding Disorder. This reclassification reflected growing neurobiological evidence suggesting that OCD has unique underlying brain mechanisms distinct from generalized anxiety disorders. The current framework specifies that symptoms must involve recurrent, unwanted thoughts or repetitive behaviors that the individual feels driven to perform.