This site has an unbelievable amount of armchair-science that gets rattled off. You are right, because depression and anxiety are primarily biological phenomena.
For example, in the talk, he points out one of the most telltale signs of depression is waking up early, which is completely backwards from the common perception that depression is someone staying in bed all day.
People looking for an actual expert discuss these things should watch Robert Sapolsky's talk: https://www.youtube.com/watch?v=NOAgplgTxfc
For example, in the talk, he points out one of the most telltale signs of depression is waking up early, which is completely backwards from the common perception that depression is someone staying in bed all day.