Dr. Gerald Klerman was a renaissance psychiatrist: not only a psychopharmacologist and psychotherapist but also an epidemiologist and community mental health advocate. Although he considered depression fundamentally a biological illness, he observed clinically how social and interpersonal stressors could aggravate his patients’ symptoms. As he said, “One of the great features of the brain is that it responds to its environment” (Weissman, 2006). Klerman was trained in psychoanalysis but also influenced by Aaron Beck’s evidence-based cognitive therapy and valued supportive therapy (Weissman, 2006). He and Myrna Weissman aimed to design a brief treatment that could be defined, practical, and efficacious. Their basic assumption was that a relationship existed between the patient’s psychiatric symptoms and his or her social and interpersonal relationships: symptoms arise not in a vacuum but in an interpersonal context (Weissman, Markowitz, & Klerman, 2000).

A few key theorists informed Klerman and Weismann’s thinking about psychotherapy throughout their own training and practice, and helped shape the principles and techniques for IPT.

Adolf Meyer, a Swiss-born psychiatrist who became president of the American Psychiatric Association, played a leading role in developing ideas in psychiatry in the early twentieth century. Meyer believed in applying a scientific approach to understanding mental illness. He was known for collecting comprehensive case histories of his patients which integrated biological, psychological, and social factors relevant to their lives. Meyer’s psychobiological model for understanding pathology stressed the importance of the patient’s relationship to his or her environment (Meyer, 1957).

Echoing Meyer’s social worldview, Harry Stack Sullivan believed that an individual’s interpersonal world was paramount to understanding psychiatric illness (Perry, 1982; Evans, 1996). Sullivan, an American psychiatrist, also practicing during the first half of the twentieth century, aimed to broaden Freudian psychoanalysis to serve patients with severe mental disorders, particularly schizophrenia. He hypothesized that maladaptive interpersonal relationships lay at the root of severe mental illnesses, characterizing loneliness as the most painful of human experiences. Therefore, clinical treatment needed to focus on developing an understanding of the individual based on the network of relationships in which he or she is enmeshed; to focus not only on the “intrapsychic, but the interactional” (Perry, 1982). Subsequently, Sullivan, along with Karen Horney, Erich Fromm, Erik H. Erikson, and others, laid the groundwork for understanding individuals based on their networks of social relationships (Perry, 1982).

Meyer’s and Sullivan’s viewpoints are congruent with the extensive literature on attachment theory, which posits that interpersonal relations are the most basic of mammalian biological needs (Bowlby & King, 2004). Attachment theorists recognize that social and emotional development starts at infancy, and that secure attachments form through having at least one strong, nourishing, and consistent connection with a caregiver. This first reciprocal relationship then shapes the dynamics of future relationships. Securely attached infants, for example, tend to become more socially skilled than their insecure peers (Bowlby, 1988).

John Bowlby, a British psychiatrist and near contemporary of Meyer and Sullivan, investigated social support in adult psychopathology by studying the effects of secure and insecure childhood attachment (Bowlby, 1988). He deduced that attachment behavior was innately biological, and that parental responses lead the child to develop attachment patterns that in turn lead to “internal working models,” which predict patterns in later relationships (Bowlby, 1988). Bolby’s theory is extremely important to the understanding of clinical depression and anxiety: whereas secure attachment can afford the individual confidence to explore and elicit support from others, any conflicts within the early caregiving connection may lead to vulnerability, mistrust in others, and avoidance of painful or fearful reactions (Kobak & Madsen, 2008; Manassis, Bradley, Goldberg, Hood, & Swinson, 1995; Warren, Huston, Byron, & Sroufe, 1997). Concerning PTSD, secure attachment should strengthen the ability to ward off negative and long-lasting effects of trauma, presumably in part through activating his or her social support network (Markowitz et al., 2009), whereas an insecurely attached individual attachment would be less likely to seek out social support, and ultimately overcome initial fearful reactions (Declercq & Palmans, 2006; Stovall-McClough & Cloitre, 2006). In fact, differing attachment styles is among the strongest predictors to date of whether an individual shows resilience after a traumatic experience or develops PTSD (Brewin, Andrews, & Valentine, 2000; Ozer, Best, Lipsey, & Weiss, 2003).

At least as much as theory, an empirical basis for understanding psychosocial aspects of depression guided the development and subsequent growth and adaptations of IPT. One of Klerman and Weissman’s goals was to educate patients about their illness and its consequences for relationships; through this understanding, a sense of purpose and motivation can emerge, helping patients to realize their own relationship difficulties and improve interpersonal problem areas. Thus, IPT was built on the relevant research literature, with an eye towards integrating key psychosocial concepts into clinical practice.

Klerman and Weissman turned to studies associating stress and life events with the onset and clinical course of depression to determine key factors to address short term psychotherapy. For example, how intimacy and social support act as protection against depression (Brown & Harris, 1978), the impact chronic, social, and interpersonal stress have on depressive onset (Pearlin & Lieberman, 1979), and epidemiological data strongly associating marital disputes and major depression (Henderson et al., 1978; Weissman, 1987). Klerman and Weissman synthesized these findings and applied them directly to their protocol, crafting the four IPT interpersonal problem areas—grief, role dispute, role transition, and interpersonal deficit—to reflect empirical findings.

By design, IPT reflected the theoretical ideas and empirical data described in this section. From the initial phase of treatment, when the therapist conducts a detailed interpersonal inventory and presents a biopsychosocial formulation, to focus on interpersonal problem areas, to techniques and tactics designed to improve social interactions, and to mobilize the patient’s social support, the treatment’s constant focus is on interpersonal targets and how they change in mood and relationships.

IPT’s distinctive qualities include: linking the individual’s psychiatric symptoms to an interpersonal crisis, understanding these symptoms as a medical illness distinct from personality or temperament, and balancing between affect-focused psychotherapy and functional application to provide opportunities for enhanced social and emotional functioning. Most psychotherapy approaches aim to help the patient reduce psychiatric symptoms, reduce social isolation, and restore a general sense of self-belief and self-reliance. However, IPT differs in its explicit attention to present functioning and interpersonal relationships. IPT does not claim to address personality functioning or character pathology, but focuses attention on alleviating symptoms through exploring, identifying, and improving problem areas within interpersonal relations (Weissman & Markowitz, 1998).

The IPT therapist frames the patient’s symptoms using a medical model, which posits that a patient should not be held responsible for his/her diagnosis, is excused for functioning at a suboptimal level while ill, and needs to work to regain his or her health (Parsons, 1951). The message remains clear throughout the treatment protocol: The patient is suffering from a treatable condition. The symptoms which make up the diagnosis are the problem, not the person. The method aims to reduce any self-blame the patient may be experiencing. The therapist encourages hope towards recovery.

IPT protocols are manually guided, but not driven by session-to-session agendas. Instead, the approach is comprised of three phases. The initial phase requires the therapist to identify the target diagnosis and the interpersonal context in which it presents. The therapist then elicits an “interpersonal inventory,” a review of the patient’s patterns in relationships, capacity for intimacy, and particularly an evaluation of current relationships. From there, the four theoretical IPT interpersonal problem areas—grief, role dispute, role transition, and interpersonal deficit—are rendered to create a focus for treatment: someone important may have died (complicated bereavement), there may be a struggle with a significant other (role dispute), the patient may have undergone some other important life change (role transition), or the individual, absent of an actual or current life event, may have trouble connecting or relating to others (interpersonal deficits).