Interpersonal mechanisms in recurrence of depression

Depression is serious disease, also because of its recurrent nature. Many people who have become depressed once, will become depressed more often. Moreover, the risk of depression seems to increase with every further episode. These observations underline the importance of gaining a better understanding of the mechanisms behind recurrence of depression. The present multidisciplinary project investigates 5 different types of risk factors for recurrence of depression (factors from the fields of personality, social cognition, interpersonal behavior, stress physiology, and interpersonal stress). The objective is to examine whether these factors jointly can explain why people recovered from a depressive episode often become depressed again. Starting point of our investigations is the personality dimension of neuroticism. Neuroticism refers to an assemblage of traits in the sphere of emotional instability, anxiety, sensitivity, moodiness, and worrying. This broad personality concept is intriguing, as it is very consistently associated with depression and various other kinds of distress while it is far from clear why. The present study aims at explicating this vague concept by relating it to factors from the 4 other fields of depression research. We expect that each of these factors explains part of the risk of depression associated with neuroticism. The factors of our interest are selected from an interpersonal point of view. Social factors play a major role in depression; in the development but particularly also in the recovery and the recurrence of the disease. We expect that interpersonal mechanisms also can serve to explain the link between neuroticism and depression. In the field of social cognition we focus on emotion perception. We investigate how patients whose depression is in remission interpret emotional expressions in faces and voices. It is known that depressives have problems with emotion perception; they often make mistakes and have a negative bias. In the field of interpersonal behavior we focus on nonverbal communication. We investigate the degree to which remitted patients and their interaction partners adjust their nonverbal behaviors to each other. People unconsciously tend to mirror each other’s behaviors and to adopt each other’s rhythms. Such matching and synchronization processes appear to be related to the quality of social interactions. Nonverbal adjustment also appears to be related to a more favorable course of the depression. In the field of stress physiology we concentrate on cortisol, the so-called “stress hormone”. Many depressed patients show elevated cortisol levels, as a result of alterations in the hypothalamic-pituitary-adrenal (HPA) axis. This hypercortisolism usually resolves upon remission. In some individuals, however, the HPA axis shows persistent dysregulations. The stress system of these individuals remains hypersensitive. These individuals also have a higher risk to develop another depressive episode. In the field of interpersonal stress we focus on “stressful life events”. These are grave experiences which tend to happen to people now and then. Stressful life events are notorious triggers of depression. Particularly stressful life events in the interpersonal sphere, like a relationship crisis or a death in the family, are known to catalyze the development of depression. Participants of this study were 104 outpatients from the Northern part of the Netherlands, treated for unipolar depression or dysthymia. These participants were subjected to a series of baseline measurements at the outset of the study, when the depression was in remission. These measurements consisted of self-report questionnaires, computer tasks, interviews, and a urine measure. After the baseline session participants were followed-up for 2 years. During this follow-up stressful life events were assessed. Participants also filled out a depression list every 4 weeks during the follow-up. Participants who scored beyond a critical value on this list at two times in succession were called for a diagnostic interview to verify whether the depression indeed had recurred. Results Our attempt to explicate the concept of neuroticism by translating it into more concrete factors from the fields of social cognition, interpersonal behavior, stress physiology, failed. Neuroticism was not related to negative emotion perception, poor nonverbal communication, or a hyperactive HPA axis. These factors (thus) could also not explain why neurotic people are more prone to experience stressful life events and why they have a higher risk of recurrence of depression. Poor nonverbal communication did contribute to the occurrence of stressful life events and –via this route- to the recurrence of depression, which was in accordance with our hypotheses. Also in line with our expectations was the finding that a hyperactive HPA axis and a negative bias in emotion perception reinforce each other and, in this way, increase the risk of recurrence. Separately, however, these factors were not predictive of recurrence.