Is gene expression/change instant, or does it take time?

"There are a lot of differences in gene expression between one healthy person and another, so it is challenging to analyze the kinds of subtle changes we are seeing and identify what changes are significant and what are just background noise. Our approach uses the latest bioinformatics tools to identify potential gene functions, generating hypotheses that can then be tested in laboratory or clinical studies."

The drugs used to treat depression, anxiety, etc., usually must be taken as prescribed over days and weeks. Over this time, the drug has a chance to stabilize in the bloodstream. Most of these drugs act as inhibitors of specific receptors. The result is the build-up of biochemicals that, in essence, make you feel better. That is the simple way to explain it.

Other drugs act in a way to affect the cell at the genetic level, meaning, telling the cell what to proteins to produce. These also take time to stabilize so that their desired effect is reliable.

How long this process takes depends on the drug. You can research the drug online, and check what timeframe they typically expect to see maximal effect.

Positive environment could only help, I suppose, but whether or not it helps greater than an environment that is neither positive nor negative would have to be scientifically proven. Of course, if "positive environment" is defined as professional therapy, then it is true that those treated with medicines and therapy do better at a significantly higher rate than those with meds alone.