Interpersonal psychotherapy (IPT) is a time-limited, diagnosisfocused therapy. IPT was defined in a manual. Research has established its efficacy as an acute and chronic treatment for patients with major depressive disorder (MDD) of all ages, as an acute treatment for bulimia nervosa, and as adjunct maintenance treatment for bipolar disorder.^{(1,2,3,4,5,6,7,8,9)} The research findings have led to its inclusion in treatment guidelines and increasing dissemination into clinical practice.

Demonstration of efficacy in research trials for patients with major depressive episodes (MDEs) has led to its adaptation and testing for other mood and non-mood disorders. This has included modification for adolescent and geriatric depressed patients^(10,11) patients with bipolar⁽¹²⁾ and dysthymic disorders;^(13,14) depressed HIV-positive⁽¹⁵⁾ and depressed pregnant and postpartum patients;^(16,17) depressed primary care patients;⁽¹⁸⁾ and as a maintenance treatment to prevent relapse of the depression.⁽⁵⁾ Most of the modifications have been relatively minor and have retained the general principles and techniques of IPT for major depression.
Non-mood targets have included anorexia, bulimia, substance abuse, borderline personality disorder, and several anxiety disorders. In general, outcome studies of IPT have suggested its promise for most psychiatric diagnoses in which it has been studied, with the exceptions of anorexia, dysthymic disorder, and substance use disorders.^(14,19,20)

IPT has two complementary basic premises. First, depression is a medical illness, which is treatable and not the patient’s fault. Second, depression does not occur in a vacuum, but rather is influenced by and itself affects the patient’s psychosocial environment. Changes in relationships or other life events may precipitate depressive episodes; conversely, depressive episodes strain relationships and may lead to negative life events. The goal of treatment is to help the patient solve a crisis in his or her role functioning or social environment. Achieving this helps the patient to gain a sense of mastery over his or her functioning and relieves depressive symptoms.

Begun as a research intervention, IPT has only lately started to be disseminated among clinicians and in residency training programmes. The publication of efficacy data, the promulgation of practice guidelines that embrace IPT among antidepressant treatments, and economic pressures on length of treatment have led to increasing interest in IPT. This chapter describes the concepts and techniques of IPT and its current status of adaptation, efficacy data, and training. The chapter provides a guide to developments and a reference list, but not a comprehensive review.

IPT traces its theoretical and clinical origins to the interpersonal psychoanalytic theory of Meyer and Sullivan and builds on work of other relational theory including object relations, particularly with regard to attachment. However, it applies this theory within a conceptual and clinical framework that differs significantly from that of Sullivan and much of relational theory. In contrast with psychoanalytically inspired schools of thought, IPT sees its goals in treating depression and other medical disorders, rather than trying to change overall personality. Pragmatically, IPT opts to narrow its focus to address the area of interpersonal life that seems to require the most immediate attention.

Acknowledging the importance of personality and early experience, IPT emphasizes the role of recent stressful events in triggering depression and other psychiatric disorders in vulnerable individuals, while it also recognizes the protective role social supports play against psychopathology. Nevertheless, IPT is less interested in discerning the cause of a depressive episode (since it assumes the aetiology of depression to be multifactorial) than in using the connection between current life events and the onset of depressive symptoms to help the patient understand and combat the episode of illness.

Compared to other psychotherapies, such as psychoanalytic psychotherapy or even cognitive behavioural therapy, IPT is relatively young. It is less concerned about maintaining an established orthodoxy than about adapting itself to the needs of the patient. Although IPT theorists have taken into account theoretical developments in psychiatry and related fields, much of IPT’s evolution has been based on the results of clinical trials. As investigations continue into IPT as a treatment for different disorders and populations, further modification of its theoretical aspects as well as techniques are likely.

IPT research has demonstrated its efficacy for major depressive disorder across a range of patient ages and contexts, and for bulimia nervosa. One large trial indicates its efficacy (modified as interpersonal social rhythms therapy, or IPSRT) as an adjunctive treatment for bipolar disorder. (6) Lesser evidence suggests the potential benefits of IPT for several anxiety disorders. (21,22) IPT has shown no advantages over control psychotherapies for dysthymic disorder or substance abuse disorders. (14,20) For depressed adolescents, IPT has shown not only efficacy but effectiveness in a school-based programme. (10,11)

Both the physician and patient guides in primary care guidelines for depression list IPT, cognitive behavioural therapy (CBT), behavioural, brief dynamic, and marital therapy as treatments for depression. IPT is spreading from its initial research base in the United States. The IPT manual has been translated into Italian, German, Japanese, Spanish, and French, and is being used ever more widely around the world. Descriptions of IPT have appeared in Spanish, Norwegian, Finnish, and Dutch journals. An International Society for Interpersonal Psychotherapy, established at the American Psychiatric Association Annual meeting in May 2000 in Chicago, has a growing membership and biennial international meetings in 2004 and 2006, and maintains a bibliography of studies.

Because IPT focuses clinically on the social context of the depressive episode, researchers have sometimes adapted IPT when applying it to different treatment populations, developing manuals for different age groups or subpopulations, and occasionally adding focal problem areas. IPT has also been used at different lengths, in different formats, in one pilot couple’s adaptation, and as a telephone intervention. Nonetheless, all these adaptations involve the basic principles that constitute IPT: a no-fault definition of the patient’s problem as a medical illness, excusing the patient from blame for his or her symptoms; and a continual focus on the relationship between the patient’s moods and life situation. The continuing growth of IPT research precludes an exhaustive description of studies. This chapter presents a selection of key research trials of IPT for mood and other disorders (see Efficacy) and offers selected references for further reading.

Although formal contraindications (i.e. situations in which IPT would worsen the patients’ situation) are not known, IPT was never intended to function as a monotherapy for patients with psychotic depression or bipolar disorder. In addition, three controlled trials have found no benefit of IPT as a treatment for substance use disorders.

Each of the four IPT interpersonal problem areas has discrete goals for therapist and patient to pursue. The therapist helps the patient relate life events to mood and other symptoms. In this section we outline the phases of IPT, as well as common strategies and techniques used in IPT treatment. We also outline some differences with cognitive behavioural therapy, to which it is often compared.