“Some people see the idea of spending time alone as distressful while others revel in being on their own. The difference could lie in the degree that each person loves themself. The more self-love, the more happiness, and therefore the less depression is a factor in one's life.”
He said living alone is pretty common in the United States, although in the rest of the world people tend to live together. This could be contributing to rising rates of depression in the United States.
“When people are living alone, they spend a lot of time in their heads, and if their heads are filled up with negativity they are going to be inclined to be more depressed than a person who monitors their negative thoughts and chooses only those thoughts that induce a feeling of wellbeing,” Erickson said. “The quality of our thoughts [determines] the quality of our lives.”
Karol Ward, a licensed clinical social worker, said in an email living alone is not necessarily a major factor in developing depression, and many of her patients haven't suffered from depression even when they lived alone.
“What's important though is to distinguish living alone from isolating," Ward said. "People who isolate from the outside world most likely have symptoms of depression.”
Alone time can be beneficial to everyone, but there needs to be a healthy balance.
“Living alone can build a sense of resiliency and strengthen the relationship you have with yourself,” Ward said. “It provides you with the space and time to discover who you are. It also can provide people with an emotional hiding place and too much time alone creates a distorted perception of self and others. If you are the only one providing perspective, it's important to keep that perspective balanced by being engaged in the world you live in.”
Natasha Tracy, a depression blogger for her website Bipolar Burble at natashatracy.com, as well as for Healthyplace.com and Healthline.com, said in an email that the risk for developing depression depends on the reason for living alone.