You harness the ability to acquire an addiction. The addiction can be few and far apart, and is very difficult to quit without the help of others. An addiction is formed if a spell is casted 3 times in a row without any other spells being casted.
Once an addiction is formed, you cannot cast any spells except for the spell that you gained an addiction with.
To lose an addiction, the DM can decide on the following requirements:
1. Not a single spell shall be casted after a long rest, until the next long rest.
2. Not a single spell shall be casted after a short rest, until the next 3 short rests.
If an addiction continues after 2 long rests, you gain the Severe Magic Addiction feat.