Thank you for writing in JA.
As you stated, excess use of marijuana and alcohol may have affected your brain negatively.
In order to improve your brain functioning and memory, you may need to focus nutrition and physical health in addition to mental exercises such as socialization, math games, reading etc..
A heart-healthy diet may improve your brain functioning and memory as it is for your heart. Focus on fruits, vegetables and whole grains. Choose low-fat protein sources, such as fish, lean meat and skinless poultry. Hydrate yourself during daytime.
Physical activity increases blood flow to your whole body, including your brain. This may help improve your memory. For most healthy adults, the Department of Health and Human Services recommends at least 150 minutes a week of moderate aerobic exercises.
reduction and relaxation techniques such as yoga, swimming, biofeedback, acupuncture, meditation
and massage therapy may be helpful for your overall health.
Please let me know if you have more questions or I have overlooked any. Warm regards,