In 1902 he received his doctorate from the University of Freiburg, receiving his MD in 1905 and subsequently working at the Herzberge asylum in Berlin-Lichtenberg. In 1923 he began work as an assistant to Karl Bonhoeffer (1868-1948) at the Charité-Berlin. In 1927 he became an associate professor.
An early interest in criminal psychology reportedly developed while in charge of high-secure wards for criminal and dangerous patients between 1908 and 1919.
In 1930 he was appointed medical director of the Heil- und Pflegeanstalt in Berlin, but because of his Jewish heritage was dismissed from his position after the Nazi takeover of Germany. In 1939 he emigrated to the United States, where he worked as a lecturer at the New School for Social Research in New York City. From 1940 he also worked at the municipal medical department of Philadelphia.
Millon, Simonsen and Birket-Smith have stated that "K. Birnbaum (1909), writing in Germany at the time of Kraepelin's later editions, was the first to suggest that the term “sociopathic” might be the most apt designation for the majority of these cases”
The term sociopathy would later gradually become popular in America, especially as expounded by psychologist George E. Partridge (1930) and adopted into early versions of the Diagnostic and Statistical Manual of Mental Disorders and is still referred to as an alternative term for antisocial personality disorder. Birnbaum proposed several subtypes of sociopathy and argued that while there may be varying degrees of 'constitutional' disposition towards disorders that could lead to maladjustment and crime, it was the effect of social forces and environments which shaped the eventual outcome.
Birnbaum published in 1914 a large encyclopedic volume on criminal psychopaths, a second and revised edition of which would be released in 1926. Reviewers at the time noted different themes—a view of constitutional psychopathy as a form of degeneration with both inherited (genetic 'taint') and prenatally acquired (through injury to 'germ plasm') types, resulting in a disposition towards mental disorder or a reduced capacity to resist anti-social tendencies; rejection of the term 'inferiors' for this category; a view that emotion is central to the disorder rather than necessarily deficient intellect; description of nearly 20 subtypes of psychopathic personalities (more akin to personality disorders than psychopathy as often defined today); a pivotal role for life events and social conditions in shaping whether someone with various psychopathic dispositions would end up engaging in antisocial or criminal behavior or not, and an insistence that even lifelong criminality does not necessarily mean underlying psychopathy.
Birnbaum suggested that some forms of psychopathy involving moral or emotional immaturity or instability could be overcome by social-educative methods or spiritual leadership.
In 1930 in an article 'The Social Significance of the Psychopathic', Birnbaum defined psychopaths as anyone who shows 'in a moderate degree dispositionally conditioned, 'constitutional', psychic deviations, and especially...in the sphere of character'. He stated this sufficiently distinguished psychopaths from the 'really insane', though not necessarily from the 'normal'.
By 1949, now in America, Birnbaum writes in regard to pathological Juvenile delinquency about the importance of considering both an immaturity of the personality from within, and environmental influences from without, and the complex interactions and pathways to conditions that result.
Pathogenesis and Pathoplasticity
Birnbaum in 1923 also coined a distinction between pathogenic and pathoplastic factors, in his work The making of a psychosis: the principles of structural analysis in psychiatry. The term pathogenic was used to refer to what causes the essential structure of a pathology, and pathoplastic to what causes the variation in the disorder between individuals or cultures. The terms are still sometimes used today in explanations for psychiatric conditions, though the concept of plasticity also has separate widespread uses as in neuroplasticity or Activity-dependent plasticity, and phenotypic plasticity). It has recently been pointed out that the distinction has generally been used to report Culture-bound syndromes in non-Western countries, despite western culture also causing its own unique forms of disorders. Moreover, cultural factors could be pathogenic as well as pathoplastic, for example by influencing epigenetic and associated neuronal processes.
- Psychose mit Wahnbidling wahnhafte Einbildingen bei Degenerativen, 1908
- Über psychopathische Persönlichkeiten. Eine psychopathologische Studie, 1909 - About psychopathic personalities. A psychopathological study.
- Die krankhafte Willensschwäche und ihre Erscheinungsformen. Eine psychopathologische Studie für Ärzte, Pädagogen und gebildete Laien, 1911 - Pathological weakness and its manifestations. A psychopathological study for doctors, teachers and educated laymen.
- Psychische Verursachung seelischer Störungen und die psychisch bedingten abnormen Seelenvorgänge, 1918 - Psychic causation of mental disorders and psychic induced abnormal mental processes
- Kriminalpsychopathologie. Systematische Darstellung, 1921 - Criminal psychopathology. Systematic presentation.
- Grundzüge der Kulturpsychopathologie, 1924 - Principles of cultural psychopathology.
- Psychischen Heilmethoden für ärtzliches Studium und Praxis, 1927 ( )
- The Social Significance of the Psychopathic, 1930
- Handwörterbuch der medizinischen Psychologie, 1930 - Concise dictionary of medical psychology.
- Kriminalpsychopathologie und psychobiologische Verbrecherkunde, 1931 - Psychopathology and psychobiological criminals.
- Richard F. Wetzell (2000) Inventing the criminal: a history of German criminology, 1880-1945
- Historical Conceptions of Psychopathy in the United States and Europe in Psychopathy: Antisocial, Criminal, and Violent Behavior, Editors Theodore Millon, Erik Simonsen, Morten Birket-Smith, Roger D. Davis, Guilford Press, 2002. Citing: Birnbaum, K (1909) Die psychopathiscene verbrecker. Leipzig: Thieme.
- Full Text Review of: Karl Birnbaum's Book (Volume 3 of a compendium with other authors) 'Psychopathic Criminals' (1914) H. C. Stevens International Journal of Ethics Vol. 25, No. 2 (Jan., 1915) (pp. 255-259) (Full title in German: Die Psychopathischen Verbrecher. Die Grenzzustainde zwischen geistiger Gesundheit und Krankheit in ihren Beziehungen zu Verbrechen und Strafwesen)
- Review of: Die Psychopathischen Verbkecher. (The Psychopathic Criminal.) By Karl Birnbaum. Berlin: P. Langenscheidt, 1914 by Berxard Glueck, Mental Hygiene VOL. Ill JANUARY, 1919 NO. 1, Page 157-166
- The Social Significance of the Psychopathic Karl Birnbaum. The Annals of the American Academy of Political and Social Science July 1930 149: 70-79
- A Court Psychiatrist's View of Juvenile Delinquents Karl Birnbaum, The Annals of the American Academy of Political and Social Science 1949 vol. 261 no. 1 55-63 doi: 10.1177/000271624926100107
- Philosophy of Psychiatry Murphy, Dominic. The Stanford Encyclopedia of Philosophy (Fall 2010 Edition), Edward N. Zalta (ed.). In turn citing Birnbaum, K., 1923. “The Making of a Psychosis,” Tr. H. Marshall, in S. R. Hirsch & M Shepherd (eds) Themes and Variations in European Psychiatry, Bristol: John Wright. 1974: 197–238.
- Association of Different Adverse Life Events With Distinct Patterns of Depressive Symptoms Matthew C. Keller, Ph.D.; Michael C. Neale, Ph.D.; Kenneth S. Kendler, M.D. Am J Psychiatry 2007;164:1521-1529. 10.1176/appi.ajp.2007.06091564
- Epigenetics and its implications for Psychology Héctor González-Pardo and Marino Pérez Álvarez, Universidad de Oviedo. Psicothema, 2013, Vol. 25, No. 1, 3-12 doi: 10.7334/psicothema2012.327