There are chair yoga versions of most postures to increase mobility, vitality and flexibility: sun salutation, forward bends, back bends, spinal twists, sitting mountain pose, eye exercises (helps computer strain) and breathing exercises (calms or energizes and increases concentration). If there aren't modifications for poses you enjoy, you can create your own. Some movement is almost always better than no movement.
Drug abuse drastically changes the brain for the worse. Addiction hijacks pleasure centers, creates ingrained behavioral patterns, and kills brain cells. The good news is you can restore the brain after addiction.
If you spend time outside in spring, summer or early fall, sooner or later you will pick up ticks in their various stages or get bitten by flies or mosquitos, all of which can carry a range of different microbes. Several of these are associated with Lyme disease.