IPT can best be understood by first describing its theoretical foundation and the framework for its delivery. This framework can be divided into the theories supporting IPT; the targets of IPT; the tactics of IPT (i.e., the concepts applied in the treatment); and the techniques of IPT (i.e., what the therapist says or does in the treatment). Though individual elements in each of these categories may be shared with other psychotherapeutic approaches, it is their unique combination which defines IPT.

• Theory : Attachment Theory² - Supported by communication theory and social theory
• Targets: Interpersonal Relationships, Social Support, Psychiatric Symptoms
• Tactics:
• Interpersonal Triad
• Biopsychosocial Model
• Interpersonal Inventory
• Interpersonal Problem Areas
• Interpersonal Formulation
• IPT Structure
• Non-Transferential Focus of Interventions
• Present Focus
• Collaboration & Goal Consensus
• Positive Regard for the Patient
• Techniques:
• Interpersonal Incidents
• Communication Analysis
• Use of Content and Process Affect
• Role Playing
• "Common" Techniques

Theory Supporting IPT

• Attachment theory ² is recognized as the primary theoretical pillar of IPT, with communication³ and social theory⁴ playing supportive roles. IPT specific research on attachment has supported this position.⁵
• Attachment theory describes the way in which individuals form, maintain, and end relationships, and is based on the premise that humans have an intrinsic drive to form interpersonal relationships with others.^{6,7,8,9,10,11}
• Attachment forms the basis for an enduring pattern of interpersonal behavior through which individuals seek care and reassurance in characteristic ways . Bowlby stated that, "The desire to be loved and cared for is an integral part of human nature throughout adult life as well as earlier, and the expression of such desires is to be expected in every grown-up, especially in times of sickness or calamity" (p.428).⁹
• Attachment theory posits that individuals become distressed when they experience disruptions in their relationships with others. Insecurely attached individuals are more vulnerable to losses, to interpersonal conflicts, and to role transitions, both because of their tenuous primary relationships and because of their poor social support networks.^12-14 These interpersonal crises - Grief and Loss, Interpersonal Disputes, and Role Transitions- are specific Interpersonal Problem Areas addressed in IPT.
• Two key derivatives of the patient's attachment style are his or her communication style and social support network .
• The patient's interpersonal communication of distress is highly dependent upon his or her attachment style.
• The patient's attachment style influences his or her ability to generate social support -- more securely attached individuals have larger social networks and many more people on whom they can call for support. Those with insecure attachment style have a paucity of social support and few adaptive interpersonal relationships.
• Both the "trees" of specific interpersonal communication and the "forest" of social support depend on the roots of attachment.
• While both Communication Theory ¹⁵ and Social Theory^16-17 remain important theoretical elements in IPT, they are conceptualized as derivatives of attachment. Patients with more maladaptive attachment styles burn their social bridges and alienate others when they ask for support. Maladaptive attachment styles also lead to inappropriate or inadequate interpersonal communications which prevent individuals' attachment needs from being met.¹⁸ Attachment is the template upon which specific communication occurs; communication reflects attachment style. The social milieu in which a patient develops interpersonal relationships strongly influences the way in which he or she is able to cope with interpersonal stress. That social milieu, or social support network, is directly influenced by the patient's attachment style.

• Summary - IPT is firmly grounded in attachment theory. Communication theory and social theory are important, but explain phenomena that are derivative from attachment. In the IPT model, biopsychosocial diatheses render a patient vulnerable to an acute interpersonal crisis. If intense enough, the crisis will trigger care-seeking behavior driven by attachment needs. If sufficient social support is available, the crisis may be diffused at this point. Insufficient social support, however, will push the care-seeking behavior even further. Patients with the ability to constructively communicate their distress and need for care may avoid overwhelming distress by enlisting additional support, but those whose attachments are maladaptive will likely communicate their need for care in ways which will drive potential care-providers away. Faced with crises in which social support is not immediately available and cannot be obtained, such patients experience psychological distress.

The Targets of IPT

• IPT is based on a Biopsychosocial Model of psychological functioning,¹⁹ which asserts that biological, psychological and social factors coalesce within an individual to produce a unique diathesis and response to stress. Given this causative model, the targets of IPT are threefold:

1) The conflicts, transitions, and losses in the patient's interpersonal relationships.

2) The patient's social support .

3) The patient's psychiatric symptoms.

• The formulation clearly identifies biopsychosocial factors as one of the three legs of the Interpersonal Triad predisposing a patient to distress. There is no evidence to date that IPT has a direct effect upon biological diatheses, so biological factors are not a primary target. Ongoing research may produce such evidence,^20-21 in which case the target of biological functioning can be added to IPT in the future.
• In addition, though there are compelling clinical and theoretical reasons to believe that IPT is likely to have an impact on personality and attachment, there is no empirical evidence to date that IPT directly impacts the psychological diatheses that predispose patients to distress. These include such factors as personality and attachment style. Both have been implicated as moderators of response to IPT,^5,18 but it is not yet known whether treatment with IPT produces change in these factors.
• Therefore, IPT (at present) is targeted at the acute interpersonal stressors and lack of social support that cause distress . It is critical to note that psychiatric symptoms, described as a primary target in the original iteration of IPT, are now regarded as a secondary target. In other words, it is through changes in interpersonal functioning and social support that symptoms are reduced --symptom reduction results from interpersonal and social changes.
• IPT is therefore conceptually distinct from treatments such as Cognitive Behavior Therapy (CBT), ²² behavior therapy, and analytic psychotherapy.
• In contrast to CBT , in which the primary focus is the patient's internal cognitions, IPT's primary targets are the patient's interpersonal relationships and social support. Though IPT may address cognitions, they are not primary targets. Similarly, though CBT and other approaches deal with interpersonal issues, they are not primary targets.
• In contrast to IPT, the primary targets of behavioral interventions , such as behavioral activation and exposure therapy, are literally the symptoms of psychopathology. Anhedonia, for instance, is targeted behaviorally by tasking the patient to schedule and engage in pleasurable activities. Phobic avoidance is targeted behaviorally through graded exposure. In IPT, symptoms of distress are reduced through changes in communication and social support.
• In contrast to analytically oriented treatments , in which the focus is the contribution of early life experiences to psychological functioning, IPT focuses on helping the patient to improve his or her interpersonal relationships and social support in the present. Neither the psychic determinism nor unconscious mental processes that characterize psychoanalytic psychotherapy²³ are invoked in IPT. The fundamental basis of IPT is that current interpersonal stressors in the context of biopsychosocial diatheses lead to psychological distress- there is no reliance on unconscious processes to explain psychological dysfunction.

IPT Tactics

Psychotherapy "tactics" can be defined as "a plan, strategy, or concept used to attain a particular goal," and IPT is characterized by a combination of them. Several, such as the Interpersonal Triad (discussed above), the Interpersonal Inventory, the Interpersonal Formulation, and the Interpersonal Problem Areas, are specific to IPT. Others, such as the Biopsychosocial Model, the Structure of IPT, the Non-Transferential Focus of Intervention, and the Present Focus of Intervention, are not unique but are necessary ingredients. Collaboration and Positive Regard are among many that are non-specific. A brief review of IPT-specific tactics follows.

IPT Tactics: The Interpersonal Inventory

The Interpersonal Inventory²⁴ is a unique feature of IPT that structures the process of history gathering and formulation of interpersonal problem areas as well as providing a reference point for conducting IPT. The Interpersonal Inventory focuses on:

• the patient's contemporary relationships;
• the history of the patient's current interpersonal problems; and
• information that is relevant to resolving the interpersonal problem- e.g., the patient's attachment style, communication style, and social support.

The Interpersonal Inventory is typically compiled during the first several sessions; however it is best considered a "work in progress" as most therapists and patients find that their understanding of the patient's relationships and the problems associated with them evolve during the course of IPT.

IPT Tactics: The Interpersonal Formulation

The IPT Formulation¹ synthesizes information from the Interpersonal Inventory and psychiatric history, creating a plausible hypothesis explaining the patient's psychological symptoms . In essence, the "formulation" is nothing more than a theoretically grounded understanding of the unique individual in therapy. It is a critical bridge between attachment theory and the patient's specific problems.

The Interpersonal Formulation provides a grounded hypothesis explaining the patient's problems and their onset, clinical manifestation, and course. That hypothesis should address the following questions:

• How did the patient come to be the way he or she is?
• What factors are maintaining the patient's problems? and
• What can be done about them?

The Interpersonal Formulation should provide a validation of the patient's experience, a mutually determined focus for intervention based on the three problem areas, and a plausible rationale for IPT.

The Interpersonal Formulation¹

IPT Tactics: Interpersonal Problem Areas

The IPT Problem Areas include Interpersonal Disputes, Role Transitions, and Grief and Loss.

• Interpersonal Disputes are simply conflicts between individuals that are causing distress.
• The process of change within relationships which occurs as a consequence of contextual changes within the patient's life is conceptualized as a Role Transition .
• Grief and Loss can be broadly understood. This problem area includes reactions to an actual death, anticipatory grief, and loss of physical health or of relationships. All of the problem areas are tactics used to maintain the interpersonal focus of treatment; they are not "diagnostic labels."

IPT Tactics: Time Limit for Acute Treatment with IPT

IPT has historically been defined as a time-limited treatment. In general, a course of 10 to 20 weekly sessions has been used for acute efficacy trials. Clinical experience, however, has been that tapering sessions over time is generally more effective than weekly treatment with an abrupt termination. In the community, weekly therapy may be provided for 6-10 weeks, followed by a gradual increase in the time between sessions as the patient improves, such that weekly sessions are followed by biweekly and monthly meetings.

Both empirical research and clinical experience with IPT have demonstrated that maintenance treatment, particularly for patients with recurrent disorders such as depression, should be provided to reduce relapse risk.²⁵ IPT is therefore currently conceptualized as a two-phase treatment:

• an intense acute phase focuses on resolution of symptoms, and
• a maintenance phase follows to prevent relapse and maintain interpersonal functioning.

There is no theoretical or practical need in IPT to "terminate" at the end of acute treatment; it is clearly not in the interest of many patients to do so.

IPT Tactics: Non-Transferential Focus of IPT

IPT has historically been characterized by the relative absence of interventions which directly address the therapeutic relationship. Though it shares this characteristic with CBT and other therapies, IPT clearly differs in this way from the dynamically oriented psychotherapies.

Clinical experience with IPT has supported the premise that focusing on the transference changes the focus of treatment from more immediate work on the patient's current interpersonal problems and social relationships to an intense experience with, and analysis of, the relationship with the therapist.¹ Addressing the patient-therapist relationship directly also shifts the therapy from one that is oriented towards improvement in social support and immediate interpersonal functioning to one that is oriented towards intrapsychic insight. This shift is a departure from the current targets of IPT.

For this reason, IPT is structured at present in a way that transference issues are less likely to emerge:

• The IPT therapist generally takes a supportive stance, rather than being neutral or opaque.
• The therapy is generally of short duration, which diminishes the intensity of the therapeutic relationship.