Cannabis and alcohol are both substances that can be harmful if used excessively or without caution. However, comparing the two substances is difficult, as they affect people differently and have different potencies. In general, alcohol is more likely to cause physical harm, while cannabis is more likely to cause mental harm.Cannabis can contain high levels of THC, the chemical that causes the 'high' associated with marijuana use. THC can cause anxiety, paranoia, and psychotic symptoms in some people. It can also impair judgment and coordination, which can lead to accidents. Cannabis use has also been linked to an increased risk of developing schizophrenia.Alcohol, on the other hand, is a central nervous system depressant. It slows down brain activity and can cause slurred speech, impaired coordination, and drowsiness. When consumed in large quantities, alcohol can cause vomiting, blackouts, and even death. Alcohol abuse can also lead to liver damage, cancer, and brain damage.So, while both substances can be harmful, alcohol is generally more harmful than cannabis.