Well, this is interesting.

The thing is, though, isn't it natural to feel anxious and depressed about the state of things?

"Last year, an anxious, depressed 17-year-old boy was admitted to the psychiatric unit at the Royal Children's Hospital in Melbourne. He was refusing to drink water. Worried about drought related to climate change, the young man was convinced that if he drank, millions of people would die. The Australian doctors wrote the case up as the first known instance of "climate change delusion."
Robert Salo, the psychiatrist who runs the inpatient unit where the boy was treated, has now seen several more patients with psychosis or anxiety disorders focused on climate change, as well as children who are having nightmares about global-warming-related natural disasters.
There is evidence that extreme weather events, such as droughts, floods, cyclones, and hurricanes, can lead to emotional distress, which can trigger such things as depression or post-traumatic stress disorder, in which the body's fear and arousal system kicks into overdrive.
After Hurricane Katrina, rates of severe mental illness - including depression, PTSD, anxiety disorder, panic disorder, and a variety of phobias - doubled, from 6.1 percent to 11.3 percent, among those who lived in affected regions, a 2006 study by the Hurricane Katrina Community Advisory Group said.
Rates of mild-to-moderate mental illness also doubled, from 9.7 percent to 19.9 percent.
"After a disaster, people can feel inadequate, like outside forces are taking control of their lives," said Joshua Miller, a professor at the Smith College School for Social Work who responds to disasters worldwide. "They can't see a positive future. They tend to lose hope or become depressed."
Severe disasters also destroy the infrastructure needed to provide mental health care, and forcibly displace people, severing social connections when people need them most, Miller said.
Climate change is expected to create about 200 million environmental refugees by 2050, according to the Intergovernmental Panel on Climate Change, the international body established within the United Nations to evaluate causes and consequences of global warming." LINK