Mistakenly thinking he was losing his eyesight and would lose his beloved job as a result, Airbus pilot Andreas Lubitz spent time visiting websites related to suicide.

The Germanwings co-pilot crashed the plane into the French Alps, killing all 150 people on board.

But CNN's Pamela Brown says Lubitz's vision issues weren't a detached retina as he thought, but a nervous psychosomatic disorder.

"He went to see a neuropsychologist over the last few years, more recently he was saying he was overburdened with work, he was very stressed out, but I'm told he never expressed anything about wanting to commit suicide."

Investigators say there was no confession letter of any kind in his apartment.

The Mental Health Foundation is encouraging people to reach out for support, rather than shy away from help for depression.

CEO Judi Clements says she's worried about the intense speculation, and the impact it could have.

"This mass broadcasting of depression connecting it to suicide, connecting to this tragic loss of life, could put people off finding support if they need it."