Smoking one or more joints a day during a year or longer is considered long-term use. However, this varies from researcher to researcher.

The health risks of this long-term use are:

• In some cases high quantity users can experience feelings of anxiety, depression and be seriously unwell.
• Cannabis influences driving ability.
• Smoking cannabis causes carcinogens to enter the body.
• During pregnancy, cannabis can have negative consequences for the fetus.
• Long-term use of cannabis may affect thinking, emotions and feelings.
• In some cases, long-term use of cannabis can lead to dependence and abuse.
• Cannabis can provoke a psychosis in people who are sensitive to it. More.

Some researchers are of the opinion that:

• Cannabis is a first step to the use of hard drugs.
• Cannabis has negative effects on the immune system.
• Cannabis influences fertility.
• Cannabis causes schizophrenia. More.
• Cannabis leads to apathy and loss of interest.
• Cannabis can cause anger, especially when trying to stop using Cananabis.

However, these statements have not been proven.