Maria, a client of mine in her 80s, could not seem to lift the cloud of depression that was increasingly darkening her life. Her adult daughter Leslie, who lived in a faraway state, kept insisting that she take an antidepressant medication. Maria resisted, sensing that a medication might lighten her mood but would not solve the underlying issue.
Eventually Maria relented, but the antidepressant gave her an equally unpleasant feeling, a sense that she had no feelings. Because the antidepressant pills blocked her ability to experience enjoyment as well as her prior sadness, Maria stopped taking them after several weeks of trial use.

What was Leslie to do? 

Leslie bought a plane ticket to go visit her mother the following month. Maybe talking with her in person would give her more understanding of how to help her mother to prevent the return of her dark and brooding moods.
To everyone's surprise, even with just her daughter's purchase of the ticket for a visit, Maria's mood lifted.  Maria began interacting more with others in her apartment building.  Her friends reported to Leslie that her Mom had begun smiling again.
What triggered Maria's turnaround from depression to ability to enjoy life again?
Maria knew. Her daughter Leslie also guessed it right away.

If you guessed that knowing that her daughter soon would be coming to visit her triggered Maria's emergence from depression, you guessed right.

A study reported in the Journal of the American Geriatrics Society validated this conclusion.  Researchers Alan Teo MD, HwaJung Choi PhD and others studied over 11,000 individuals aged 50 and older.  The study tracked evidence of depression over and up to two years, and also the frequency with which participants had email, telephone, letter or face-to-face contact with their children, other family members, and friends.

The results of this depression prevention study were clear.  

Family members and friends who sent e-mail, telephone, and letter communications to their elders had little to no impact on their elders' depression vulnerability.
By contrast, the more face-to-face contacts, in person, that el
ad with family members and friends, the lower the likelihood that the elders would experience depression.  If this face-to-face contact occurred once or twice a month, the contact was helpful, if the contacts occurred once to twice per week, the impact was all the stronger.
As described in an article by reporter Sue Byrne in Consumer Reports, "People who had the most contact, at least three times a week face to face, had the lowest rates of depression two years later," this according to Alan Teo, MD, the lead author of the study and an assistant professor of psychiatry at Oregon Health & Science University.

The bottom line is that loneliness invites depression. Social contact lifts spirits.

Though not always. If friends or family members visited but were quarrelsome, the argumentative interactions lessened the positive effects of social connecting.
In general however, the moral of the story is clear: Visit your elders. Frequent visits to elders, visits that give them face-to-face contact with their friends and family members, make a significant difference in the emotional state of senior citizens. Or as the authors of this study put it, "Frequency of in-person social contact with friends and family independently predicts risk of subsequent depression in older adults." More visits predicts less depression.