In Islam Khumir (Arabic word for Wine) is Haram as Allah says:
O you who have believed, indeed, intoxicants, gambling, [sacrificing on] stone alters [to other than Allah ], and divining arrows are but defilement from the work of Satan, so avoid it that you may be successful. [5:90]
Allah also says:
They ask you about wine and gambling. Say, "In them is great sin and [yet, some] benefit for people. But their sin is greater than their benefit." And they ask you what they should spend. Say, "The excess [beyond needs]." Thus Allah makes clear to you the verses [of revelation] that you might give thought. [2:219]
Now that we know that Khumir (wine) is forbidden by Allah, let's visit this hadith:
أَخْبَرَنَا سُوَيْدٌ، قَالَ أَنْبَأَنَا عَبْدُ اللَّهِ، عَنْ مُحَمَّدِ بْنِ عَجْلاَنَ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " كُلُّ مُسْكِرٍ حَرَامٌ وَكُلُّ مُسْكِرٍ خَمْرٌ " .
The Prophet [SAW] said: "Every intoxicant is unlawful and every intoxicant is Khumir ."
This means that anything that intoxicates you is Khumir, at the same level of forbiddance. This is the case because at the time of the Prophet there were other known intoxicants from many cultures, and the prophet forbade them all.
Same hadith was reported multiple times as well. This intoxicants include Weed, Drugs, Marijuana, etc.. Those will make you lose your mind (in some cases worst than light drinking).
Smoking on the other hand has a different ruling. It is not an intoxicant, but keeps you alert. This is the same as Coffee, tea, Khat (a Yemenite plant). Scholars are divided on the issue of smoking, some say it is not Haram and some say it is. Those who say it is, say it is because of the many harmful additive cigarettes contain and for the fact that nicotine is addictive.