Original articleDog-assisted intervention significantly reduces anxiety in hospitalized patients with major depression
Introduction
Major depressive disorder is the most common of all psychiatric disorders and ranks among the leading causes of disease burden worldwide [1]. Accordingly, about 1 in 5 people will experience a major depressive episode at some point in their lives [1]. However, a complex relationship between neurotransmitter dysbalance, hypersensitivity to stress, stressful life events, and genetic vulnerability has been suggested in the development of depressive symptoms [2]. Recent discussions on the clinical effectiveness of antidepressant drugs especially in mild depressive disorders have raised the need for alternative and additional treatments with fewer side effects [3].
Investigators have hypothesized that companion animals may serve to lower levels of stress and anxiety [4], [5], [6], [7]. As domesticated dogs have been protecting their human companions for about 15,000 years, it seems plausible that dogs provide a feeling of safety and comfort not found in more traditional inpatient therapies. In a first published pilot study, depressed patients waiting for electroconvulsive therapy were found to have a significant reduction in fear (37% from baseline) after spending 15 min with a therapy dog and its owner [6]. Moreover, a reduction of anxiety in mood disorder patients has been observed in comparison with relaxation training [6].
Several authors have reported lower blood pressure readings among patients when a previously unknown companion animal is present during various stressful activities [7], [8], [9]. In addition, stress parameters such as cortisol have been shown to decrease after a 15 min dog interaction [10]. Hypercortisolism has been linked to depression and anxiety where the dysregulation of the hypothalamic–pituitary–adrenal axis is a well-observed pathophysiological factor [11], [12]. Although introduced to clinical practice in the early 1960s, animal-assisted activities and therapies have not been scientifically tested until today with the exception of a handful of pilot studies [6].
In this pre- and post-treatment controlled crossover study we therefore addressed the question whether state anxiety measured with the State-Trait Anxiety Inventory (STAI) might decrease in acutely depressed hospitalized patients in the presence of a friendly dog.
Section snippets
Patients and methods
A controlled crossover design was used in which subjects served as own controls. A total of 12 acutely depressed patients (six male, six female, age: 40.5±10 years) were recruited for this study at Charité University Medicine Berlin. Disease onset (age: 25.5±11 years) was comparable in all participating patients. The number of previous hospitalizations was 4.1±2. The local ethics committee approved the study and written informed consent was obtained accordingly from all subjects. Patients met
Statistical analysis
Wilcoxon test for matched pairs was employed to test for influences of the assistance of dogs in the interview. Results are presented as means±one standard deviation. Analyses were computed using statistical software (SPSS 16.0®). A p value of p<0.05 was considered significant while p<0.10 was accepted in order to detect trends.
Results
At the time of the study, all patients were hospitalized with major depression at the Charité Campus Mitte hospital, most of them because of suicidality. No participants had to be excluded according to the exclusion criteria. Mean Beck depression inventory score of patients was 24.5±8. Some low scores were possibly due to a problem of self-reporting. Mean STAI score before the control session was 50.41±10 and after the control session it was 48.0±9. Mean STAI score was 47.0±11 before the
Discussion
A 30 min intervention in the presence of a dog significantly reduced state anxiety in acutely depressed patients in our study, compared to a control intervention.
Our result is in line with one previous pilot study with inpatients in an acute psychiatric setting that also found significant reductions in anxiety after 30 min with a therapy dog [6]. Moreover, in otherwise healthy adults using wheelchairs, implementation of service dogs has shown to decrease negative affect and depressive symptoms
Financial support
The study was not supported except for income received from the primary employer, the Charité University Medicine Berlin.
Conflict of interest
Undine E. Lang received a travel award from Janssen-Cilag and speaker honoraria from AstraZeneca, Lundbeck and Eli Lilly & Co and travel expenses from AstraZeneca. The other authors declare that, except for income received from their primary employer, no financial support or compensation has been received from any individual or corporate entity; and there are no personal financial holdings that could be perceived as constituting a potential conflict of interest.
Acknowledgements
We would like to thank Prof. Christian Grosse-Siestrup, Prof. Ralf Uebelhack, and Prof. Andreas Heinz for their encouragement to work with dogs.
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