In our depression research programme the following steps and themes can be distinguished:
- Epidemiological studies on the prevalence of persistent (chronic) depression and its delineation from and association with other syndromes
- Studies investigating the chronic processes in persistent depression
- Intervention studies evaluating treatments of persistent depression
- Studies examining (self-)management support programmes for chronically depressed patients
Epidemiological studies are crucial in identifying the determinants of and, ultimately, preventive measures for chronicity. They are also instrumental in determining the overlap with and distinction from the course of other depressive and comorbid mental disorders.
Thought contents, in particular dysfunctional cognitions, are assumed to drive the cognitive processes in depression, but possibly, and more importantly than these maladaptive thinking patterns, it is cognitive reactivity, and thus the degree to which they are reactivated, that is modulated by the depressed mood. In depression, executive functions are also affected by - among other causes - selective information processing, manifesting in areas such as attention, memory and interpretation. These so-called cognitive biases in information processing may then cause various problems. Depressed people will thus recall negative memories more easily than non-depressed controls (mood-congruent recall) and also retain information with a negative load better (mood-congruent encoding), while they tend to retrieve general information better from memory than they do specific information (overgeneral memory). This latter phenomenon is not mood-dependent and associated with an unfavourable prognosis, making overgeneral memory a vulnerability factor. Ruminating is also considered an important vulnerability factor both in the onset and maintenance of depression. As it is assumed that these various cognitive vulnerabilities play a role in the development of chronicity, they merit further scrutiny in people with a persistent depressive disorder.
Intervention research is highly relevant in chronic depression. To date, the use of psychological treatments is still limited and deserves expansion. Such interventions can best make use of cognitive techniques, as is the case in cognitive bias modification (CBM). This promising technique helps patients to improve the way they process information and to modify automatic thinking patterns. Also, mindfulness-based cognitive therapy (MBCT) is showing potential. Current depression research focuses on MBCT in relapse prevention and the evidence of its effectiveness in reducing depressive symptoms is growing, making it an attractive add-on to the treatment of chronic depression. Both interventions help modify cognitive functioning in depression.
Self-management is another viable strategy meriting further research to see to what extent people suffering from (persistent) depression can be empowered by reinforcing their self-management skills. An explorative research about experiential knowledge, experiential expertise and the use of self-management strategies is a first step towards a deeper understanding of these concepts. The qualitative study ‘The strength of depression’ aims to gain insight in coping with depression from patients’ perspectives.
Overview of ongoing studies:
- DeMeTer: Randomised clinical trial into the effectiveness of mindfulness-based cognitive therapy (MBCT) for treatment-resistant depression.
- CoDe or Cognitions in Depression. Study of the usefulness of cognitive bias modification (CBM) as a diagnostic tool for (chronic) depression.
- Dreams: Depression remission after repetitive transcranial magnetic stimulation (rTMS). RCT into the effectiveness of rTMS in therapy-resistant depression.
- ZemCad: Self-management for persistent anxiety and depression. Multisite study into the cost-effectiveness of a self-management training programme for patients with a chronic depression.
- Cognitrain for depression: RCT into the effectivenes of Cognitive Bias Modification (CBM) in depression treatment delivered in specialised treatment centres.
- Intertrain for depression: RCT into the effectiveness of Interpretation Bias Modification (IBM) in depression treatment delivered in specialised treatment centres.
- Behavioural activation (BA) for depressed older adults: RCT into the effectiveness of BA for depressed older adults receiving treatment in primary care settings.
- The strength of depression: self-management, experiential knowledge and experiential expertise of depression. A qualitative study about experiential knowledge of longer-term depression.