Is depression a chronic mental illness?

Over the past few decades, theory and research on depression have increasingly focused on the recurrent and chronic nature of the disorder. These recurrent and chronic forms of depression are extremely important to study, as they may account for the bulk of the burden associated with the disorder. Paradoxically, however, research focusing on depression as a recurrent condition has generally failed to reveal any useful early indicators of risk for recurrence. We suggest that this present impasse is due to the lack of recognition that depression can also be an acute, time-limited condition. We argue that individuals with acute, single lifetime episodes of depression have been systematically eclipsed from the research agenda, thereby effectively preventing the discovery of factors that may predict who, after experiencing a first lifetime episode of depression, goes on to have a recurrent or chronic clinical course. Greater awareness of the high prevalence of people with a single lifetime episode of depression, and the development of research designs that identify these individuals and allow comparisons with those who have recurrent forms of the disorder, could yield substantial gains in understanding the lifetime pathology of this devastating mental illness.

Does early intervention increase latency to relapse in major depressive disorder? Re-evaluation with cognitive behavior therapy.

BACKGROUND: Major depressive disorder (MDD) has been studied in relation to its propensity for remission and likelihood of relapse. While the general clinical lore suggests that early intervention benefits treatment outcome, the empirical validation of this assumption is inconclusive. Specifically, no studies have been conducted concerning Time to Treatment Entry and long-term clinical course for MDD. METHODS: For the current study, 53 participants received 16-weeks of cognitive behavioral therapy (CBT). Participants who remitted (n=41) from their depression were then inducted into a longitudinal follow-up protocol. RESULTS: Longer Time to Treatment Entry was predictive of longer time to relapse. A greater number of previous depressive episodes was associated with decreased Time to Treatment Entry. LIMITATIONS: A more elaborate protocol could be designed in order to explore the nature of treatment effects and Time to Treatment Entry within one study. CONCLUSIONS: CBT may be the most effective for patients who have delayed seeking treatment. Although the present study adds to the developmental neurobiological assumptions of Post [Severe depressive disorders (1994) 23-65] concerning affective 'kindling,' it also challenges the kindling theory's assumptions concerning early intervention.

Life stress and the symptoms of major depression.

Life stress has been found to be associated with onset of depression and with greater severity of depressive symptoms. It is unclear, though, if life stress is related to particular classes or specific symptoms in depression. The association between severe life events and depressive symptoms was tested in 59 individuals diagnosed by Research Diagnostic Criteria with endogenous primary nonpsychotic major depression. As predicted, life stress was associated principally with cognitive-affective symptoms, not somatic symptoms. There also was a consistent association across different assessment methods between severe events and suicidal ideation. Finally, associations held specifically for severe events occurring before onset, not for severe events occurring after onset. Symptom variation in major depression is related specifically to severe stressors before onset and includes primarily cognitive-affective types of symptoms. There is an especially pronounced association of prior severe stress with suicidal ideation. The implications of stress-symptom associations are addressed for enlarging understanding of symptom heterogeneity and subtype distinctions in major depression.

A comparison of two life stress assessment approaches: prospective prediction of treatment outcome in recurrent depression.

Research on life stress has been characterized by inconsistent results, which some researchers attribute to different assessment methodologies. Generally, studies have used either self-report checklists or investigator-based interviews. To test whether different results are derived from these approaches, the authors compared information from a self-report measure of life stress with the additional data available from a follow-up investigator-based measure in prospectively predicting the outcome of treatment for recurrent major depression. The 2 approaches produced different results, with investigator-based life events predicting lower probability of remission and self-report life events either predicting increased likelihood of remission or not predicting at all. The results demonstrated that methodology may account for some of the inconsistencies in the life stress literature.

Life events and depression in adolescence: relationship loss as a prospective risk factor for first onset of major depressive disorder.

Although stressful life events have consistently been linked to the onset of major depressive disorder (MDD), most research has not distinguished 1st episodes from recurrences. In a large epidemiologic sample of older adolescents (N = 1,470) assessed at 2 time points, the risk conferred by a recent romantic break-up was examined as a predictor of 1st onset versus recurrence of MDD. Results indicated a heightened likelihood of 1st onset of MDD during adolescence if a recent break-up had been reported; in contrast, a recent break-up did not predict recurrence of depression. These results held for both genders and remained significant after controlling for gender. Additional analyses to determine the discriminant validity and specificity of these findings strongly supported the recent break-up as a significant risk factor for a 1st episode of MDD during adolescence. Implications of these findings and subsequent research directions are discussed.

The generation of life events in recurrent and non-recurrent depression.

BACKGROUND: The stress generation hypothesis proposed by Hammen (1991) holds that depressed individuals generate stressful conditions for themselves, which lead to recurrence. The original test of this hypothesis compared dependent life events in women with recurrent depression to medical and normal controls. Two further research questions emerged from this work: (a) do individuals with a history of many depressive episodes generate more dependent life events than depressives with fewer episodes?; and (b) what is the aetiological relevance of any stress that may be generated? METHODS: The present research tested differences in dependent and independent events between depressed individuals who had experienced: (a) no previous major depressive episodes; (b) one previous episode; and (c) two or more previous episodes. We predicted that, based on the stress generation hypothesis, recurrent depressives would show more dependent events than people without a depression history, and that these generated stressors would be of aetiological importance for precipitating recurrence (i.e. severe events in the 3 months preceding recurrence). RESULTS: Recurrent depressives experienced significantly more total dependent events than first-onset depressives in the 12 months, but not the 3 months, preceding their episode. CONCLUSIONS: Although the findings supported the general premise of stress generation, the aetiological relevance of the generated stress for recurrence requires further study.

Response to cognitive-behavioral therapy in depression: effects of pretreatment cognitive dysfunction and life stress.

Response to cognitive-behavioral therapy (CBT) for depression is variable and the factors that account for differences in response are not yet well established. Level of cognitive dysfunction and the occurrence of negative life stress have been theorized as patient variables, which may account for differences in response to CBT. The relationship between response to CBT and the interaction of cognitive dysfunction with negative life events was examined in a sample of 53 depressed outpatients. Overall, there was little support for the prediction of a difference in acute outcome between patients with or without pretreatment cognitive dysfunction and negative stressors.

Comparison of cognitive models of depression: relationships between cognitive constructs and cognitive diathesis-stress match.

The authors examined the relationship between the cognitive components of the Beckian and Hopelessness models of depression by administering measures of dysfunctional attitudes, attributional style, and life stress to a sample of 59 depressed adults. Confirmatory factor analyses indicated that dysfunctional attitudes and attributional style load on separate factors as opposed to a single factor. Additional analyses revealed that depressed persons conforming to diathesis-stress criteria according to each model were largely independent of one another. Results supported the conclusion that the Beckian and Hopelessness models of depression describe distinct cognitive constructs and refer to distinct subsets of depressed persons.

Gender differences in cognitive diathesis-stress domain match: implications for differential pathways to depression.

The frequency of cognitive diathesis-stress match was compared in a sample of depressed women and men to investigate hypotheses positing gender differences in the relation of cognitive diathesis-stress factors to depression. Depressed women were more likely to have experienced a match between a cognitive diathesis and a preonset negative stressor compared with depressed men. Comparisons of women and men on the cognitive and stress variables singly yielded differences in stress variables but not in cognitive variables. Depressed women were more likely to have experienced a negative severe event before the onset of depression and had a greater frequency of negative interpersonal events. Results supported the hypothesis of gender differences in pathways to depression.

Life stress and treatment course of recurrent depression: II. Postrecovery associations with attrition, symptom course, and recurrence over 3 years.

Life stress was studied in relation to postrecovery attrition, symptom course, and recurrence of depression over 3 years. Participants were 67 individuals with recurrent depression who had responded to treatment. Life stress was assessed for the prior 12 weeks at acute treatment entry (T1), initial recovery (T2), and after 17 weeks of sustained recovery (T3). Severe life events at T1 predicted greater attrition, a more favorable postrecovery symptom course, and a lower likelihood of recurrence over 3 years. Life stress at T2 was not predictive of outcomes. Finally, undesirable life events at T3 tended to predict a worse symptom course and a higher likelihood of recurrence, particularly for individuals on medication. The findings are discussed in terms of (a) different processes influenced by life stress over time and (b) limitations of existing longitudinal research for studying the effects of life stress over prolonged intervals.