Loss of brain power. Be filled again?.

Dr. says i have symptoms of schizophrenia, some say mixed anxiety depression disorder , some say OCD... but i dont have any of these, its just due to worst incidents in my life that they look like these disease symptoms... Reality is , i just lost my brain power due to depression ( due to incidents) and over thinking & over imagination while consuming ganja...... but when i went to hospital with heavy head and heavy headache, they sent me to neurologist... they done MRI and all ...and nothing came...they sent me back with few headache medicines... so i just want to ask, is medical science not developed that much that i drink a syrup for 5 days and brain power will be filled again??... i dont know its been 5 years taking medicines and i improved moderate...