These "chemical imbalance" narratives tend to do more harm than good by giving patients an idea that their symptoms are purely external to their own choices, and therefore completely out of their own control. Unfortunately, it's very difficult to convince suffering patients that they have some control over their situation without also implying personal blame for their problems, which doesn't go over well. The idea that the problem is faultless ("It's not you, it's just your brain!") and that the solutions are effortless ("This pill will fix your chemical imbalance") is just too tempting. The alternatives ("Read this book on study habits, leave your phone in another room while studying, use timeboxing...") are an unappealing alternative.
Don't get me wrong: Medications can and absolutely do help people, but this idea that the problem can only be treated via medication is demonstrably false. The most successful patients use a combination of medications, therapy, and healthy habit-forming. The least successful patients tend to give up on everything except the medication, reaching for ever-increasing doses or trying to play games of on-days/off-days or saving up extra medication. That's a losing battle.
There's definitely a healthy balance of smart lifestyle choices, coupled with medication for those who truly struggle and need to just get from zero to 1.
> Unfortunately, it's very difficult to convince suffering patients that they have some control over their situation without also implying personal blame for their problems
I also see it as a big part of the problem, that it's difficult to convince people that they do have control over their lives. In many psychotherapy books, when therapists describe various cases, this is a corner stone of a therapy success: a patient understanding that they do have control over their situation. That it's not the outer world that is so demanding that it leaves them no choice, but them choosing to cope in a particular way, and that there are other ways to react and cope.
For the reference, where I live we don't have ads for prescription medication. On the other hand everything tends to be diagnosed as depression and treated with antidepressants, no matter what symptoms are.