After all the recent tragedies, why are environmental factors ignored by mental health experts?

EVERY suicide is a tragedy. The ones left behind are stigmatised. Psychologists find an explanation in underlying depression. But what causes depression? Depression is a mental disorder.

Do we have to blame ourselves only for not coping with stress, for being sad, or are there any factors other than our personalities?

I suffer from multiple chemical sensitivity (MCS), a condition in which the blood-brain barrier is permanently broken down, so that even the smallest traces of chemicals can cause severe symptoms like headaches, tremors, insomnia, disequilibrium, etc.