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Furry Companions May Be The Best Drug For Stubborn Depression

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To be sure, the positive effect of pet ownership on mental health is already well known, hence the many organizations training and placing service dogs with people suffering from PTSD or extreme anxiety and the booming – and sometimes abused – trend of emotional support animals.

Yet scientific research aimed at quantifying the therapeutic impact of such animals has yielded mixed results and the investigations are often too muddled by confounding factors to draw strong conclusions.


But now, a new study by a pair of Portuguese psychiatrists has found that adopting a dog or cat can greatly alleviate the pernicious type of depression that does not respond to conventional treatments.

As described in the Journal of Psychiatric Research, 33 formerly pet-free patients with treatment-resistant major depressive disorder (TR-MDD) experienced significant improvement in depression symptoms and social functioning just 12 weeks after going along with the doctors’ suggestion to bring home a pet, and incredibly, more than one-third no longer met the criteria for having the disorder. None of the 33 control patients who did not adopt pets showed a meaningful difference in depression scores.  

The study participants were chosen from among 80 patients at the author’s outpatient psychiatric clinic who had not experienced depression relief after 9 to 15 months of treatment that included regular therapy sessions and at least two courses of anti-depressant medication. Hoping to provide the first-ever evidence of how pets can serve as an adjuvant to these approaches, Drs Mota Pereira and Fonte recommended pets to each of these individuals without telling them that the aim of the adoption was to combat their TR-MDD.

Thirty-three people said yes to the idea: 18 adopted one dog, 7 one cat, and 7 two dogs. Forty-seven of them said no for unknown reasons, and from this group, the authors picked 33 patients to serve as controls – a move that they concede introduces some bias into the results.


For the next 12 weeks, all patients continued to attend sessions and take the medication that they had been on for at least six weeks prior to the study’s start. Using the standard Hamilton Rating Scale for Depression (HAM17) and Global Assessment of Functioning Scale (GAF), Mota Pereira and Fonte observed that new pet owners began to show signs of depression relief in as little as four weeks. Statistically significant differences between the pet and control group emerged at week 8 in regards to HAM17 scores and week 12 in regards to GAF scores – a rating of how mental illness affects one’s ability to function in day-to-day life. Male and female patients appeared to respond similarly to their furry companions.

Because the patients were not randomized to receive a pet or not, the results of this study must be taken with a grain of salt. However, it does provide compelling motivation for future investigations to try to replicate the findings. Perhaps additional research can also illuminate how, on a psychological or neurological level, animals have this effect.

Speculating on the matter, the authors stated: “One of the reasons that could explain our results is that pets compel to counteract one of the main symptoms of depression, anhedonia. Anhedonia is the inability to experience pleasure from activities usually found enjoyable, e.g. exercise, hobbies, or social interactions."

They note that dogs may provide the added benefit of forcing people into physical activity and often new social situations.


“However, it is not a cure for this type of disease and the benefits will only occur in people that appreciate domestic animals and have time, attention and money (afford food and veterinary care) to spend with them.”

[H/T: Psychology Today]


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