What are the effects of long term benzodiazepines use?
I suffer from a devastating anxiety since childhood that progressed to a point where I had a panic attack almost every day. Benzodiazepines (namely diazepam or clonazepam) help my symptoms immensely and allow me to function much better in school, relationships, and other areas of life. I have managed to taper myself to a fairly low dose, but can't see myself being able to go off of them in the future.
I have seen and talked to multiple doctors, and over the last two years I have tried other medications, but nothing except benzos have worked as well for me: Sertraline, Lithium, Olanzampine, Paroxetine, Fluvoxamine, Imipramine, Fluoxetine, Quetiapine and Bupropion absolutely didn't work. Others had some benefits that were outweighed by the side effects like (on an efficacy scale): Clomipramine > Venlafaxine > Escitalopram.
I am concerned about the effects of long term benzodiazepines use. While some papers appoint 'em as very harmful in a long term others don't. Some scientists argue that it's related to permanent cognitive loss (although my notes in college improved since I started taking benzos), dementia and so on... while others say that it is just part of marketing campaign to rocket the "z drugs" prescription.
Is there any research on long term HUMAN models? I mean... benzos are around since the 60's... if they were that harmful shouldn't we've already noticed it?