Emil Kraepelin (1856–1926)

Emil Kraepelin was a physician who studied people with mental illness in the late nineteenth and early twentieth centuries in modern-day Germany. Kraepelin's examination and description of the symptoms and outcomes of mental illness formed the basis for his classification of psychiatric disorders into two main groups, dementia praecox, now called schizophrenia, and manic-depressive psychosis, now called bipolar disorder. He was one of the first physicians to suggest that those researching mental illness should gain scientific knowledge only through close observation and description. However, Kraepelin also believed that genetics played a role in the development and course of mental illness and characterized mentally ill people as weak-willed, which some have argued contributed to stigma about mental illnesses that persist today. Although some historians have pointed out issues with Kraepelin’s teachings, Kraepelin helped to establish psychiatry as a clinical science, which prompted future experimental investigations into mental illness.

Kraepelin was born on 15 February 1856 in Neustrelitz in the Duchy of Mecklenburg-Strelitz in what is now Germany. Kraepelin’s father, Karl Kraepelin, was a music teacher, actor, and opera singer who, according to historian Hannah Decker, was an alcoholic. Kraeplin remained with his mother, who he recalls with fond childhood memories in his autobiography, Memoirs, after his parents separated. Kraepelin’s brother, named Karl Kraepelin after their father, was ten years older than Kraepelin and later in life became an international authority on insects, scorpions, centipedes, and spiders. In his autobiography, Kraepelin wrote that his brother introduced him to natural sciences such as botany, the study of plants, and the theory of evolution. While Kraepelin was still in grade school, a friend of Kraepelin’s father, physician Louis Krueger, brought Kraepelin with him to observe his medical rounds in the country. Kraepelin wrote in his autobiography that it was that experience that led him to study medicine. Kraepelin discussed his interests with Krueger, who advised Kraepelin to become a psychiatrist, which would allow him to study a form of psychology while earning a physician’s salary.

Kraepelin completed his early schooling in present-day Neustrelitz. He then went to the University of Leipzig in Leipzig, Germany, in 1874 to begin his medical training, and transferred to a different university in Würzburg, Germany, in the summer of 1875. There, he attended a course in clinical psychiatry, which encompasses the evaluation, diagnosis, and treatment of patients with mental health concerns. Kraepelin passed his preliminary medical examination in the winter semester between 1875 and 1876. However, around 1877, Kraepelin read psychologist Wilhelm Wundt’s book, Physiological Psychology, which outlined Wundt's methods and ideas about psychology. After reading Wundt's book, Kraepelin returned to the University of Leipzig to study with Wundt, who helped establish the experimental study of psychology. Wundt had written that he planned to establish psychology as a scientific and experimental science. Kraepelin followed Wundt's recommendations in his development of a scientific approach to the study of mental illness based on observation and careful description.

In 1877, while Kraepelin was still studying in Leipzig, the physician Franz von Rinecker offered Kraepelin a position as an assistant physician at his clinic in Würzburg, Germany. Kraepelin accepted and returned to finish his studies in Würzburg while working at Rinecker’s clinic. Kraepelin later wrote in his autobiography that work at Rinecker’s clinic was intense and upsetting, but that he became accustomed to it after a few weeks. Kraepelin subsequently completed his medical studies in Würzburg in 1878. He took his first position as a physician that same year at the Upper Bavarian district asylum, a mental hospital in Munich, Germany. Then, in 1879, Kraepelin enrolled at the University of Munich in Munich, Germany, to complete his doctoral studies. Working with the psychiatrist Bernhard von Gudden as his doctoral supervisor, Kraepelin completed a thesis on “The Place of Psychology in Psychiatry” and completed his degree in 1883.

In 1866, Kraepelin became a professor of psychiatry at the University of Dorpat, now called the University of Tartu, in what is now Estonia. Until then, Kraepelin had primarily been engaged in clinical work taking care of patients. However, as a professor, he was able to conduct his own psychological experiments, applying the methods Wundt had developed for psychology to psychiatry so he could understand and characterize mental illnesses. During his time at the University of Dorpat, Kraepelin carried out various experiments such as measuring mental reaction times, studying the mental effects of caffeine, tea, drugs, and fatigue, and even using hypnosis. He used the results of such experiments to create disease categories describing mental illnesses. Those descriptions appeared in a textbook he published titled Psychiatrie: ein Lehrbuch für Studierende und Ärtzte (Psychiatry: a Textbook for Students and Physicians), hereafter Textbook. In his book, Kraepelin outlined the guidelines for certain psychiatric diagnoses and states that whether the patient improves or fails to improve is an important indicator to the specific classification of psychiatric illness. Throughout his life, Kraepelin published eight updated editions of the textbook. Shortly after being promoted to a university lecturer in 1884, he married Ina Schwabe, to whom he had been engaged for nearly thirteen years. The couple had eight children altogether, but only four survived infancy.

The Textbook contains Kraepelin’s ideas about mental illness, as well as detailed descriptions of his patients and their symptoms. In the Textbook, Kraepelin proposed his system for classifying mental disorders. At the time, psychiatrists did not have a system in place for explaining mental disorders that did not have a known physical cause. One theory was that what appeared to be many mental illnesses was really just one disease. Other researchers put forth that all mental illnesses were due to a brain disease that researchers had not yet discovered. Still, a third idea prevalent at the time was that mental illness was due to an inherited process of degeneration, or the gradual mental and physical decline of a family over generations. Most historians claim that Kraepelin did not agree with any of those ideas. Rather, he used observation and clinical description to develop a new way to classify mental illness, emphasizing the observation of the clinical symptoms over time. He studied thousands of patients and their clinical histories and recorded all relevant information on what he called counting cards so that he could more easily compare them.

He remained at the University of Dorpat until 1891, when he left to become professor of psychiatry and director of the psychiatric clinic at Heidelberg University in Heidelberg, Germany. While Kraepelin was at Heidelberg, he published the sixth edition of his Textbook. In that edition, he introduced his idea on a distinction between dementia praecox, now called schizophrenia, and manic-depressive psychosis, now called bipolar disorder. Schizophrenia is a condition in which a person abnormally interprets reality, and may experience hallucinations, delusions, or disordered thinking. Bipolar disorder is a condition in which a person has severe high and low moods that may quickly change. In the late nineteenth century, psychiatrists only diagnosed patients with one of those illnesses if they were exhibiting symptoms of insanity, alienation, or dementia. Those conditions were generally characterized based on delusions, overall perceived mental incompetence, or other events occurring in the mind rather than as a result of a bodily process.

Throughout his career, Kraepelin also frequently attributed the roots of the mental illnesses he studied to a lack of volition, or will power. According to historian Hannah Decker, he thought that many symptoms he observed in his patients were due to a weakness of will, something he increasingly thought about as he got older. He would call some people with mental illness or symptoms of mental illness hysterical or weak-willed. Kraepelin used such terms with people who displeased him, according to Decker, such as alcoholics, soldiers suffering from the trauma of being at war, and women, who he characterized as overly impulsive and argued that their most valuable characteristics would be endangered if they entered the working world. Decker states that Kraepelin often judged his patients with mental illnesses as being weak, lazy, careless, or senseless. Decker characterizes Kraepelin’s beliefs about volition as a form of prejudice against those who he saw as lacking it.

Additionally, some have criticized Kraepelin’s work as stigmatizing mental illnesses, especially schizophrenia, because of his adherence to degeneration theory. Degeneration theory held that mental illnesses were the result of inherited familial defects that became more severe with each generation. According to Joseph Zuber, Gerald Oppenheimer, and Richard Neugebauer, who all researched either psychiatry or history of science in the twentieth and twenty-first centuries, degeneration theory was prevalent among psychiatrists and medical researchers in other fields of Kraepelin’s time. While Kraepelin did not fully subscribe to degeneration theory, he nonetheless wrote that mental illnesses could be partially explained by inheritance of detrimental genes according to Zuber and colleagues. Zuber and colleagues state that degeneration theory produced fear and shame in people with mental illness and their families, and the stigma about mental illness that degeneration theory caused persists in modern times.

Despite the problems scholars have pointed out with Kraepelin’s work, many of his clinical findings formed the basis for modern understandings of mental illnesses. Kraepelin was one of the first to distinguish between and describe the illnesses now known as schizophrenia and bipolar disorder. Additionally, the main features of his classification system continue to exist in many current international classification systems of mental disorders, such as the Diagnostic and Statistical Manual of Mental Disorders 5, or DSM 5, and the International Classification of Disease 10, or ICD-10.

Kraepelin died after a short illness of influenza and pneumonia in Munich, Germany, on 7 October 1926.