Hi there. Mephedrone can cause hallucinations, nausea
, vomiting, blood circulation problems, anxiety, paranoia, fits, delusions, concentration, poor short term memory, increased heart rate, anxiety, depression, dilated pupils, etc. The short-term effects of mephedrone use include mood swings, severe pain, nosebleeds, hallucinations or purple skin. Causes of twitching need to be investigated.