There are six different types of drug use
Obviously this is the first time(s) the person uses the drug. So it is a short type of drug use. People will either stop using or move onto another type of drug use such as recreational. As a result this type of drug use often occurs in the teens or the early twenties. However it can occur at other times such as with a mid-life crisis when the 40 year old man experiments with marijuana for the first time. It is usually associated with with a new developmental stage in a persons life. When a person moves to a new stage of development they often experiment with a variety of new things including drug use
Experimentation is a normal part of human psychology
If the person smokes marijuana for about 1 to 10 times this can be experimental use. If the person keeps using then the type of use changes. Some people stop then. Some only experiment just a few times. With marijuana it is not uncommon to hear people say they tried it and it just made them paranoid, so it was not pleasant and they stopped. Or others say it just made them feel sick. For some reason the drug does not agree with the person’s body chemistry, the experience is unpleasant and thus stops quickly. This also happens with alcohol. To some people it just makes them feel sick. Ego states involved in this type of drug use are Free Child, Rebellious Child and possibly Adult.
The goal of experimental use is to experiment and find out what this thing called cannabis feels like. Once they have used a few times they have experimented and thus the reason disappears. As the drug use is new the source of supply can be quite tenuous. It came from a friend of a friend of a friend, so the use can be erratic as the supply is erratic and the quality is often quite poor as they are at the bottom of the food chain at that point.