Additive effects, but no synergistic interaction of stressful life-events and genetic loading in affective disorders

Does stress play a significant role in bipolar disorder? A meta-analysis

BACKGROUND

There is evidence that stressful life events (LE) play a crucial role in the etiology of bipolar affective disorder (BD). However, primary studies, as well as narrative reviews, have provided mixed results. The present meta-analysis combined and analyzed previous data in order to address these inconsistencies.

METHOD

Forty-two studies published in 53 records were identified by systematically searching MEDLINE, PsychINFO, and PSYCHINDEX using the terms "bipolar disorder" OR "manic-depressive" OR "bipolar affective disorder" OR "mania" AND "stress" OR "life event" OR "daily hassles" OR "goal attainment". Then, meta-analyses were conducted.

RESULTS

Individuals diagnosed with BD reported more LE before relapse when compared to euthymic phases. They also experienced more LE relative to healthy individuals and to physically ill patients. No significant difference in the number of LE was found when BD was compared to unipolar depression and schizophrenia.

LIMITATIONS

When interpreting the present meta-analytic findings one should keep in mind that most included studies were retrospective and often did not specify relevant information, e.g., if the LE were chronic or acute or if the individuals were diagnosed with BD I or II. We could not entirely rule out a publication bias.

CONCLUSION

The present meta-analyses found that individuals with BD were sensitive to LE, which corroborates recent theoretical models and psychosocial treatment approaches of BD. Childbirth, as a specific LE, affected individuals with BD more than individuals with unipolar depression. Future studies that investigate specific LE are warranted.

Life events and the onset of celiac disease from a patient's perspective

Stressful events have been investigated in various immune-mediated diseases but not in celiac disease. Our aim was to examine the relationship of stressful events assessed by the standardized interview of Paykel with the diagnosis of celiac disease in comparison to patients, with a diagnosis of gastroesophageal reflux disease used as the control group. Adults with celiac disease (n = 186) reported more frequent and more severe life events in the years prior to the diagnosis than control patients (n = 96) (67.2% vs. 37.5%, p < 0.001, mean Paykel score 11.5 vs. 13.4, p = 0.001, respectively). Findings were not significantly different between celiac disease and control patients for the time lapse between the event and the diagnosis (mean 5.5 vs. 5.7 months). Pregnancy was defined as a negative event by 20.3% of celiac women, but never by control women. Findings were confirmed when analyses were repeated in the subgroup of patients of both groups with diagnosis made within one year of onset of symptoms. Data indicate that, before diagnosis, the number of stressful events in celiac disease was more frequent although less severe than in the control group suggesting that life events may favor the clinical appearance of celiac disease or accelerate its diagnosis.

Life events and onset of a new phase in bipolar affective disorder

BACKGROUND

There is an increasing focus on the impact of psychosocial factors and stressors on the course of bipolar affective disorder. The life event research has revealed many biases and the results are conflicting. In a prospective study we examined the relationship between life events and affective phases in a group of bipolar patients with a long duration of the disease.

METHODS

A group of patients with at least three admissions to hospital for bipolar disorder was followed every 3 months for up to 3 years. At each examination an evaluation of affective phase was made according to the Hamilton Depression Scale, the Newcastle Depression Rating Scale and the Bech-Rafaelsen Mania Rating Scale. Moreover, the patients were rated according to the Paykel Life Events Scale. Their current medical treatment was noted.

RESULTS

Fifty-six patients (19 men and 37 women) were included in the study. Women experienced a significantly higher number of life events than men. In 21% of the 353 examinations of women, a new phase was preceded by life events whereas this was the case only in 8% of the 152 examinations of men. In 13% of the male examinations the patients were in a manic phase and in 5% in a depressive phase. In 5% of the female examinations the patients were in a manic phase and in 15% in a depressive phase. Half of the women's depressive phases were preceded by life events, but none of the depressive phases of men. The categories of life events preceding the depressive phases presented a significant overweight of somatic ill health and conflicts in the family.

CONCLUSION

We found a gender difference in the course of bipolar affective disorder, as women had a significantly higher number of depressive episodes than men and men had a higher number of manic episodes than women. In bipolar patients with long duration of disease a significant number of depressive episodes in women were preceded by negative life events. Somatic health problems and conflicts in the family were significant factors preceding new depressive phases.

Life events, stress and depression: a review of recent findings

OBJECTIVE

To review recent empirical prospective studies on the relation between life event stressors and depression.

METHOD

A systematic literature search focusing on predictive studies was carried out from 1980 to early 2001 using Medline, Embase and PsychInfo.

RESULTS

The empirical findings for the most part support clinical impressions of the relation of stressors to depression but at the same time provide some clearer understanding in relation to differences of stressor impact on depression type and on index episode, relapse or recurrence. Twin studies now provide the strongest evidence of the relative magnitude of effect of environmental stressors and genetic factors: the former explains at least as much of the variance in depression as our genes.

CONCLUSIONS

Continuing research into life events and depression have been fruitful especially those studies assessing the effect of stressors in combination with other aetiological variables such as genetic factors.

Signal transduction mechanisms and behavioral sensitization to stimulant drugs: an overview of cAMP and PLA2

Behavioral sensitization refers to the progressive increase of behavioral responses to psychomotor stimulants, which provides a model for the intensification of drug craving and relapse alleged to underlie addiction in humans. Mechanisms related to sensitization may also contribute to schizophrenia and bipolar disorder. While the phenomenon has been observed for years, only recently have molecular or intracellular mechanisms associated with behavioral sensitization been studied. An overview of cAMP and PLA2 (intracellular, signal transduction mechanisms) relevant to behavioral sensitization will be presented.

Age of onset in affective disorder: its correlation with hereditary and psychosocial factors

BACKGROUND

Affective disorders probably have a multifactorial aetiology, both biological and psychosocial factors may be of importance at onset as well as at relapses. The aim of the study was to investigate how the age of onset of bipolar and unipolar disorder relates to family history of affective disorder, early parental separation and life events. A second purpose of this study was to analyze the importance of life events preceding the first and subsequent episodes of affective disorder.

METHODS

The case records of 282 patients (161 females/121 males; mean age 56) were investigated. They all had a DSM-IV based diagnosis of either bipolar I/II (67%) or unipolar (33%) disorder. Variables, such as family history, early parental loss and life events according to Paykel life events scale, were examined.

RESULTS

We found a significantly lower age of onset in bipolar patients with a family history of affective disorder (28.9 vs. 33.9 years). Bipolar patients with preceding life events had a higher age of onset (33.1 vs. 28.3 years). Moreover, bipolar patients with heredity, had less life events at onset. For the bipolar, as well as the unipolar group, life stressors more frequently preceded the first episode of affective disorder than the subsequent episodes.

LIMITATIONS

The major limitation of this study is the retrospective approach, with e.g. difficulties to decide whether a life event plays a role in aetiology of affective disorder or is its consequence.

CONCLUSIONS

Bipolar patients with high constitutional vulnerability have an earlier age of onset and need less stress factors to become ill. Better knowledge about the stress- and the vulnerability-factors in affective disorder might contribute to development of individually tailored therapeutic strategies in future.

The stress-reaction process and the adaptive modification and reorganization of neuronal networks

On the basis of a comprehensive definition of the stress-reaction process (SRP), the neurobiological and psychological consequences of this process, which are elicited by either controllable or uncontrollable stress, are described. We conclude that controllable stress triggers the stabilization and facilitation of neuronal networks involved in the generation of appropriate patterns of appraisal and coping, whereas uncontrollable stress favors the extinction of inappropriate patterns and the reorganization of neuronal connections underlying certain inappropriate behaviors. Both controllable and uncontrollable stress-reaction processes are therefore inherent challenges to the development and essential prerequisites of the adaptation of an individual's behavior to the demands of the ever-changing external world. The overabundance, as well as the lack, of either kind of SRP may lead to different psychodevelopmental failures and psychiatric disturbances.