I will explain to you how being cut off from the natural world can cause depression.
Isabel Behncke in Lost Connections: Uncovering the Real Causes of Depression—And the Unexpected Solutions by Johann Hari

I took a trip to East Africa for 18 days of wildlife photography in Kenya and Tanzania. The animals were excited, spirited, and expressive — they ran, jumped, hunted, and played. A pride of lazy lions slept and sunned themselves while mischievous cubs played and irritated their elders who cuffed them gently. Large groups of giraffes loped gracefully across the plains.

Two or three cheetahs quietly stalked gazelles. A silent leopard carried a young wildebeest into a tree to feast on for the next two or three days. Elephants lumbered in front of a gigantic and snow-covered Mount Kilimanjaro as filled with excitement, I fumbled with my camera. The daily drama for food played itself out in front of us. What an authentic and powerful place this is.

I observed how life in the Ngorongoro Crater, a collapsed volcano with steep walls, had evolved and cooperated so all of the elements fit together to create a balanced whole — an ecosystem upon itself.

I watched the chaos of the annual wildebeest migration as hundreds of thousands of animals chased the rain. I began to sense the underlying order, programmed genetically over thousands of years, of their seemingly insane behavior. Hundreds of thousands of wildebeest births occur over three weeks during the annual migration to water. This mass birth preserves the species, for predators cannot kill that many young before they can care for themselves.

Wildlife photographer Mitsuaki Iwago calls this underlying order “Okite — a law of natural life that’s neither glamorous nor indulgently savage.” Nature adapts and designs and all of life plays an authentic role, with an unimaginable intelligence. Order exists beneath chaos — observable, in part, to the mindful. I wondered if the rich diversity of Africa will survive humankind’s abuse, greed, ignorance, and arrogance. I hope so but am doubtful.

When I got home, I visited a zoo and the animals looked different to me: They looked depressed: lethargic, dispirited. Parrots may pull their feather out; horses may start swaying; elephants may grind their tusks down. Many animals lose their desire to have sex, hence the difficulty of breeding in captivity. Africa showed me the authentic life of animals free in their natural environment. I wish we didn’t have zoos that take the life of the animals.

Do humans become more anxious and depressed when they don’t spend time in nature? Many studies tell us we do. And, conversely, depressed people show dramatic improvement when they spend time in nature. We are animals too and need time in nature if we want to be healthy. We need to move. We need to feel alive!

Isabel Behncke said that we create our own mental and physical zoos that keep us captive. Being deprived of natural settings, we can become prisoners of our egos. Our problems seem bigger than they are; our thoughts consume us. Being out in nature, we experience awe: we feel the largeness of the cosmos. We feel our connections with everything around us. Our perspectives change. Our egos shrink. Nature helps us be healthy.

Anne Lindbergh told the story of Andre Gide who was traveling fast through the jungles of Africa. One morning the native guides sat in a circle and refused to leave the camp. When Gide urged them to get moving they looked at him and with firmness said, “Don’t hurry us-we are waiting for our souls to catch up with us.” We need to learn to be present at the moment and be part of and learn from nature. My brother hikes mountain trails and says he does mindful walks: One mile per hour. His photos show his detailed awareness of the natural world.

During the past year of captivity due to Covid-19, I walked in the house. It was good for me. But, I didn’t feel alive. I was doing a task. I couldn’t wait to finish each day. The last few weeks, I walked outside, and I could feel the positive contrast.
I felt alive.