According to the community based website Curetogether spending time with a pet helps people with depression.
Is there peer reviewed research that makes the same recommendation?
A University of Leicester team tested the effect of regular swimming sessions with dolphins on 15 depressed people in a study carried out in Honduras.
They found that symptoms improved more among this group than among another 15 who swam in the same area - but did not interact with dolphins.
All the volunteers who took part in the trial stopped taking antidepressant drugs or undergoing psychotherapy at least four weeks beforehand.
Two weeks later, both groups showed improved mental health, but especially so among patients who had been swimming with the dolphins.
And here is a study about how a cat improved depressive symptoms in elderly people
28 subjects with chronic age-related disabilities living in a nursing home ... were assigned to a pet-therapy intervention group.
Results showed that patients with animal interaction had improved depressive symptoms and a significant decrease in blood pressure values.
This study is about animal-assisted therapy in adult college students
[The study] investigated the effects of animal-assisted therapy (A-AT) on self-reported depression in 44 college undergraduates.
Results confirmed the positive influence of A-AT in this cohort.
Here is a study about "The Effects of Animal-Assisted Therapy on Anxiety Ratings of Hospitalized Psychiatric Patients"
This study examined whether a session of animal-assisted therapy reduced the anxiety levels of hospitalized psychiatric patients and whether any differences in reductions in anxiety were associated with patients' diagnoses.
It was concluded:
Animal-assisted therapy was associated with reduced state anxiety levels for hospitalized patients with a variety of psychiatric diagnoses, while a routine therapeutic recreation session was associated with reduced levels only for patients with mood disorders.