Well into the eighteenth century, the only types of mental illness – then collectively known as “delirium” or “mania” – were depression (melancholy), psychoses, and delusions. At the beginning of the nineteenth century, the French psychiatrist Pinel coined the phrase “manie sans delire” (insanity without delusions). He described patients who lacked impulse control, often raged when frustrated, and were prone to outbursts of violence. He noted that such patients were not subject to delusions. He was referring, of course, to psychopaths (subjects with the antisocial personality disorder). Across the ocean, in the United States, Benjamin Rush made similar observations.

In 1835, the British J. C. Pritchard, working as senior Physician at the Bristol Infirmary (hospital), published a seminal work titled “Treatise on Insanity and Other Disorders of the Mind”. He, in turn, suggested the neologism “moral insanity”.

To quote him, moral insanity consisted of “a morbid perversion of the natural feelings, affections, inclinations, temper, habits, moral dispositions, and natural impulses without any remarkable disorder or defect of the intellect or knowing or reasoning faculties and in particular without any insane delusion or hallucination” (p. 6).

He then proceeded to elucidate the psychopathic (antisocial) personality in great detail:

“(A) propensity to theft is sometimes a feature of moral insanity and sometimes it is its leading if not sole characteristic.” (p. 27). “(E)ccentricity of conduct, singular and absurd habits, a propensity to perform the common actions of life in a different way from that usually practised, is a feature of many cases of moral insanity but can hardly be said to contribute sufficient evidence of its existence.” (p. 23).

“When however such phenomena are observed in connection with a wayward and intractable temper with a decay of social affections, an aversion to the nearest relatives and friends formerly beloved – in short, with a change in the moral character of the individual, the case becomes tolerably well marked.” (p. 23)

But the distinctions between personality, affective, and mood disorders were still murky.

Pritchard muddied it further:

“(A) considerable proportion among the most striking instances of moral insanity are those in which a tendency to gloom or sorrow is the predominant feature … (A) state of gloom or melancholy depression occasionally gives way … to the opposite condition of preternatural excitement.” (pp. 18-19)

Another half century were to pass before a system of classification emerged that offered differential diagnoses of mental illness without delusions (later known as personality disorders), affective disorders, schizophrenia, and depressive illnesses. Still, the term “moral insanity” was being widely used.

Henry Maudsley applied it in 1885 to a patient whom he described as:

“(Having) no capacity for true moral feeling – all his impulses and desires, to which he yields without check, are egoistic, his conduct appears to be governed by immoral motives, which are cherished and obeyed without any evident desire to resist them.” (“Responsibility in Mental Illness”, p. 171).

But Maudsley already belonged to a generation of physicians who felt increasingly uncomfortable with the vague and judgmental coinage “moral insanity” and sought to replace it with something a bit more scientific.

Maudsley bitterly criticized the ambiguous term “moral insanity”:

“(It is) a form of mental alienation which has so much the look of vice or crime that many people regard it as an unfounded medical invention (p. 170).

In his book “Die Psychopatischen Minderwertigkeiter”, published in 1891, the German doctor J. L. A. Koch tried to improve on the situation by suggesting the phrase “psychopathic inferiority”. He limited his diagnosis to people who are not retarded or mentally ill but still display a rigid pattern of misconduct and dysfunction throughout their increasingly disordered lives. In later editions, he replaced “inferiority” with “personality” to avoid sounding judgmental. Hence the “psychopathic personality”.

Twenty years of controversy later, the diagnosis found its way into the 8th edition of E. Kraepelin’s seminal “Lehrbuch der Psychiatrie” (“Clinical Psychiatry: a textbook for students and physicians”). By that time, it merited a whole lengthy chapter in which Kraepelin suggested six additional types of disturbed personalities: excitable, unstable, eccentric, liar, swindler, and quarrelsome.

Still, the focus was on antisocial behavior. If one’s conduct caused inconvenience or suffering or even merely annoyed someone or flaunted the norms of society, one was liable to be diagnosed as “psychopathic”.

In his influential books, “The Psychopathic Personality” (9th edition, 1950) and “Clinical Psychopathology” (1959), another German psychiatrist, K. Schneider sought to expand the diagnosis to include people who harm and inconvenience themselves as well as others. Patients who are depressed, socially anxious, excessively shy and insecure were all deemed by him to be “psychopaths” (in another word, abnormal).

This broadening of the definition of psychopathy directly challenged the earlier work of Scottish psychiatrist, Sir David Henderson. In 1939, Henderson published “Psychopathic States”, a book that was to become an instant classic. In it, he postulated that, though not mentally subnormal, psychopaths are people who:

“(T)hroughout their lives or from a comparatively early age, have exhibited disorders of conduct of an antisocial or asocial nature, usually of a recurrent episodic type which in many instances have proved difficult to influence by methods of social, penal and medical care or for whom we have no adequate provision of a preventative or curative nature.”

But Henderson went a lot further than that and transcended the narrow view of psychopathy (the German school) then prevailing throughout Europe.

In his work (1939), Henderson described three types of psychopaths. Aggressive psychopaths were violent, suicidal, and prone to substance abuse. Passive and inadequate psychopaths were over-sensitive, unstable and hypochondriacal. They were also introverts (schizoid) and pathological liars. Creative psychopaths were all dysfunctional people who managed to become famous or infamous.

Twenty years later, in the 1959 mental health Act for England and Wales, “psychopathic disorder” was defined thus, in section 4(4):

“(A) persistent disorder or disability of mind (whether or not including subnormality of intelligence) which results in abnormally aggressive or seriously irresponsible conduct on the part of the patient, and requires or is susceptible to medical treatment.”

This definition reverted to the minimalist and cyclical (tautological) approach: abnormal behavior is that which causes harm, suffering, or discomfort to others. Such behavior is, ipso facto, aggressive or irresponsible. Additionally it failed to tackle and even excluded manifestly abnormal behavior that does not require or is not susceptible to medical treatment.

Thus, “psychopathic personality” came to mean both “abnormal” and “antisocial”. This confusion persists to this very day. Scholarly debate still rages between those, such as the Canadian Robert, Hare, who distinguish the psychopath from the patient with mere antisocial personality disorder and those (the orthodoxy) who wish to avoid ambiguity by using only the latter term.

Moreover, these nebulous constructs resulted in co-morbidity. Patients were frequently diagnosed with multiple and largely overlapping personality disorders, traits, and styles. As early as 1950, Schneider wrote:

“Any clinician would be greatly embarrassed if asked to classify into appropriate types the psychopaths (that is abnormal personalities) encountered in any one year.”

Today, most practitioners rely on either the Diagnostic and Statistical Manual (DSM), now in its fourth, revised text, edition or on the International Classification of Diseases (ICD), now in its tenth edition.

The two tomes disagree on some issues but, by and large, conform to each other.