Cannabis (marijuana and hash)

Published 20 December 2005. Updated 2 September 2009.

Cannabis products include hash, hash oil and marijuana. They are made from a hemp plant called Cannabis Sativa. For marijuana, the inflorescence and the higher sprouts are used. Hash and hash oil is produced from the resin of the hemp. The intoxicating substance of cannabis is the fat-soluble THC, delta-9-tetra-hydrocannabinol. Hash oil is the strongest of the cannabis products, marijuana usually the mildest.

Cannabis is smoked in a pipe or in a hand-rolled cigarette, either blended with tobacco or smoked as such. Cannabis can also be taken mixed in tea or with baked goods. A newer way of using cannabis is to steam (vaporise) the cannabis, which is done by passing hot steam through the marijuana leaves. Home cultivation of cannabis plants has increased significantly in Finland in recent years.

The effects of cannabis depend on the user’s state of mind and the company the user is in. Whether cannabis is used on its own or together with other intoxicants and whether the user is a novice or an experienced user also have an influence on the effects of the drug. The immediate effects often include talkativeness, happiness, intense feeling of hunger and loss of inhibitions. Physical effects include elevated pulse and bloodshot eyes.

During the initial period of acute intoxication as well as during the later stage of intoxication, the user may become quiet, withdrawn and sleepy. The effects of larger doses are stronger and may include strengthened sensations of colours, light and sounds, states of panic and nausea. Effects also include deterioration of short term memory and of the ability to perform so that the user cannot carry out tasks that require concentration, e.g. driving a car.

Current research shows that, depending on the user’s sensitivity and tolerance, long-term cannabis use may increase the risk of schizophrenia or depression. There are no conclusive research results yet on the effects of continuous, long-term use of cannabis. Still, smoking cannabis will increase the risk of respiratory diseases and lung cancer, as cannabis smoke contains considerably larger amounts of tar than regular tobacco. Inhaling the smoke deeply, such as with a water pipe or ‘bong’, increases the amount of hazardous substances taken into the lungs and, to a certain extent, into the bloodstream. Taking cannabis orally eliminates this risk, but on the other hand it is harder to control the size of the dose as the effects start later and are more intense than when cannabis is smoked.

Some long-term, high-scale users of cannabis suffer mental changes; typical symptoms include apathy, unwillingness to face challenges, loss of interest in hygiene and sex and avoiding social contacts. This symptom complex is called amotivational syndrome, and it is found mostly among adolescents and young adults. There may be a risk of amotivational syndrome during the period in life when one’s success in studies and work can affect the rest of one’s life.

Regular long-term use leads to increased tolerance, and the user needs to take increased doses to achieve the desired effect. Regular use of cannabis may also lead to psychological dependence. Those who use cannabis daily in large doses may also develop a physical dependence. If cannabis is smoked blended with tobacco, a psychological and physical dependence on nicotine will develop quickly. Withdrawal symptoms of cannabis include sleep disorders, nervousness, sweating and loss of appetite. The physical withdrawal symptoms last approximately a week.

The active substance in cannabis, delta-9-tetrahydrocannabinol (THC), is stored in the body’s fat cells and is released only very slowly. When long-term cannabis use is stopped, drug screening tests may still show positive results for cannabis for over a month.

Ulrich Tacke
M.D., lecturer in pharmacology, University of Kuopio

Sanna Sairanen
M. Pol. Sc.

For more information

Drugs and the Brain animation explains, how different substances affect users’ thoughts and actions through the transmitters in the brain.