Maybe meaning is not a property of the universe, but a symptom (conceit?) of consciousness.
Maybe what we're "meant" to do is not set in stone.

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I am not a mouse. I don't see how visual hyperstimulation in mice is analogous to ADD/ADHD in humans.

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Psychology and Psychiatry are so nearly solid science, but they're leagues away at the same time. It's hard to get good data when the person under scrutiny can lie (or unintentionally misrepresent) their mental state. It's hard to draw good conclusions when there is so much variance in the human population and circumstance to life.

To the degree that a human is a chemical machine, it makes perfect sense to solve chemical problems with chemicals. There is certainly a lot of information to be gleaned by taking this view of health and wellness. However, we all know that the chemical machine is (in a sense) only the vehicle of our personality... and if you'll pardon the metaphor... fixing the car doesn't make a good driver.