In Conceptions of Modern Psychiatry1 Sullivan traces psychiatry's double descent, from medicine and from the social traditions of healers and sages. He defines the field as the study of interpersonal relations, which the psychiatrist can know only as a participant observer. The Interpersonal Theory of Psychiatry2 makes personality the relatively enduring pattern of recurrent interpersonal situations that characterise a life. The theory rests on the one-genus postulate, that human beings are far more alike than different. Sullivan's 1946 foreword to the Conceptions attacks what he calls the "delusion of unique individuality".
Conduct, in the Conceptions, is organised around two pursuits: satisfactions, tied to the body, and security, tied to culture. Anxiety, which Sullivan distinguishes from fear and pain, is caught empathically from the start. The infant's needs call out tenderness in the mothering one, while her anxiety reaches the infant through empathy. Avoiding anxiety becomes the mainspring of development (The Interpersonal Theory of Psychiatry2).
Out of approval, disapproval and overwhelming anxiety, the infant forms the personifications good-me, bad-me and not-me. From them grows the self-system, or self-dynamism, which is built from the appraisals of others and controls what enters awareness. What it cannot admit persists as dissociated. Its security operations keep anxiety down at the cost of learning from experience. Chief among them are selective inattention and dissociation (The Interpersonal Theory of Psychiatry2). Clinical Studies in Psychiatry7 treats selective inattention, sublimation, dissociation and the paranoid dynamism as the processes by which anxiety is kept out of awareness, and gives selective inattention a chapter of its own.
Experience is organised in three modes. The prototaxic is an undifferentiated flow. The parataxic links what merely occurs together. The syntaxic is consensually validated in shared language (The Interpersonal Theory of Psychiatry2). Parataxic distortion is living a present relationship through illusory figures from the past. Sullivan put the term in place of Freud's transference and widened it to every relationship, not only the patient's relation to the psychiatrist (Conceptions of Modern Psychiatry1). He illustrated it with a patient who found, after hundreds of hours, that she had been seeing him as a fat old man with white hair.
Sullivan followed development through a series of epochs: infancy, childhood, the juvenile era, preadolescence, and early and late adolescence. A child whose need for tenderness is met with rebuff may come to expect hostility and turn malevolent. The juvenile era teaches competition, compromise and cooperation among peers. In preadolescence the capacity for love first appears, in intimacy with a same-sex chum. This friendship brings consensual validation (Conceptions of Modern Psychiatry1). Early adolescence brings the lust dynamism and its collisions with the needs for intimacy and security. Personality is not settled in the first years, and each era offers a chance to repair earlier warps (The Interpersonal Theory of Psychiatry2). In Personal Psychopathology6 preadolescent friendship is already the first relationship in which another person's well-being matters as much as one's own.
Mental disorders, in this view, are patterns of inadequate or inappropriate interpersonal relations, continuous with ordinary living (The Interpersonal Theory of Psychiatry2). Clinical Studies in Psychiatry7 reads hysteria, obsessionalism, hypochondria, manic-depressive psychosis, schizophrenia and paranoid states as patterns of interpersonal living. The schizophrenia papers argue against the Kraepelinian picture of dementia praecox as a fixed organic deterioration. They treat schizophrenia as a human way of meeting a crisis in living, whose strangest thinking and symbols remain within the human range and can be understood with enough contact. The illness typically breaks out in panic, after a collapse of self-esteem before experiences the person cannot integrate. Its early regressive features are conservative, attempts to reintegrate experience through older modes of thought, while its malignant features mark a turn toward lasting dissociation. Some patients come out of an episode more capable than before. Treatment is a psychotherapy modified from psychoanalysis, which lowers anxiety and builds a relationship instead of relying on free association (Schizophrenia as a Human Process5). The Conceptions also offers ten developmental syndromes, such as the self-absorbed, the ambition-ridden and the chronically adolescent person, as better guides to a person's future than the categories of mental disease.
The clinical method follows from the theory. The Psychiatric Interview3 defines the interview as primarily vocal communication between two people on an expert–client basis. Its aim is to clarify the interviewee's characteristic patterns of living, in a way from which he expects to benefit. The psychiatrist is an expert in interpersonal relations and a participant observer, never a neutral mirror, and must stay aware of his own share in the field from which the data arise. Anxiety in both participants is the chief obstacle to learning anything. How things are said, in tone, pauses and digressions, is evidence as much as what is said. Sullivan divides the interview into the formal inception, the reconnaissance, the detailed inquiry and the termination, and uses the developmental history as the frame of reference for the inquiry.