The latter not only included cases of alternating mania and melancholia, but all cases of mania, and seemed to include all depressions.

Kraepelin regarded psychiatric disorders as disease entities based on a medical, neurological model, with specific, organic etiology and pathology. He believed that manicdepressive insanity was largely independent of psychological stress. While such stress might precede the onset of some attacks, it could not be the true cause, but merely something akin to a trigger mechanism. He did, however, regard some pathological depressions as psychogenic #HTS assay keyword# in origin. While he did not completely clarify his views on their position in his classification, or how they were to be distinguished from manic-depressive illness with incidental stress, he appeared Inhibitors,research,lifescience,medical to regard them as a separate, but relatively small and unimportant, group. At the same time as Kraepelin and

others were establishing a generally accepted classification of the major psychiatric disorders in terms of disease entities based on a medical model and organic etiology, another growing school of European psychiatrists were developing a very Inhibitors,research,lifescience,medical different approach. These were the psychoanalysts. Freud and Abraham, in a perceptive group of studies, developed a theory of the origin Inhibitors,research,lifescience,medical of depression in relation to actual or symbolic losses of a love object. Here was a theory regarding the origin of most, if not all, depressions as psychogenic. The case material of Kraepelin, and others like him, consisted of severely ill patients in institutions. The first depressed patients studied psychoanalytically were also severely ill. Subsequently, increasing attention began to be paid to milder forms of disorders, at first particularly by the psychoanalysts.

Psychological theories of causation became more widely accepted for these disorders. A challenge now arose as to how to reconcile these theories with older ones of organic Inhibitors,research,lifescience,medical causation. Adolf .Meyer, a Swiss psychiatrist who became the highly Annual Review of Biophysics influential head of the Henry Phipps Psychiatric Clinic at Johns Hopkins University, moved away from the idea of clearcut disease entities, and viewed all psychiatric disorders as reaction types, or psychobiological reactions of the organism to stress.5 Both psychological and organic factors had to be taken into account. Others preferred to retain a view which kept separate the two types of psychiatric disorders. On one hand were the psychoses, severe illnesses requiring admission to an asylum, and presumed to have organic causes. On the other hand were the neuroses, milder and not requiring admission to an institution, regarded as more related to psychological stress, and amenable to psychological treatment.