The Use of Marijuana in the Treatment of Psychological Disorders

The Use of Marijuana in the Treatment of Psychological Disorders

The use of marijuana as a medicinal treatment has been met with much controversy. Public opinion of marijuana use, whether recreational or medical is sharply divided. Some dismiss medical marijuana simply as a hoax to make it legal. Others are adament about the unique medicinal properties that it has. Both sides have used science as the backbone of their case, supporting claims that the others have deemed false. In this report I will objectively make a case that marijuana has a legitimate use in the world of medicine and mental disorders. The use of marijuana in the treatment of disorders hasn't reach a level to which there is definitive evidence to support a wide array of claims. In this paper I contend that the use of marijuana agonists and antagonists can have an significant impact on a number of psychological, central nervous system and motivational disorders. Marijuana agonists have the best application when used for the treatment of loss of appetite, pain, anxiety, vomiting, nausea, and epilepsy. Marijuana antagonists applications include schizophrenia and anxiety. For this paper I will concentrate on three promising applications of marijuana which include pain, anxiety and movement disorders.

Several developments have greatly helped the study of marijuana. These included the isolation the cannabinoid receptor, the discovery of endogenous cannabinoid ligands and the isolation of the primary psychoactive components of marijuana; Delta-8 and Delta-9 THC. These greatly enhance our understanding of marijuana and its use as a medicine.

One important factor in studying cannabis is the fact that it is composed of many different chemicals. The constituent chemicals are called "cannabinoids". There are approx. 66 cannabinoids and they are grouped into 11 different types based on their chemical similarity. They fall into two categories, psychoactive and non-psychoactive. Psychoactive properties are what gives the user a "high" when they smoke marijuana. This is the main reason that many people use marijuana today. Other properties that are exhibited by marijuana but is not part of the "high" are ones like pain relief and increased appetite. These are all aspects of what happens when a user smokes marijuana, but are separate and distinct events. One of the troubles with marijuana research is the inability to separate the "high" from the medicinal aspects of psychoactive cannabinoids. They can never be separated because the way the "high" feeling is produced is the same chemical route by which desirable effects are mediated. While enjoyed by most people, the high can induce adverse mood reactions. These reactions occur most frequently in inexperienced users or when people take a much higher dose than usual. These usually disappear within hours but have significant effects including anxiety, paranoia, panic, depression, depersonalization, delusions and hallucinations. These are not desirable effects for the medical use of marijuana and must be considered when seeking to apply marijuana as a treatment.

One of the most cited effects of marijuana use is its ability to diminish pain. There have been many studies about the effectiveness of marijuana as a pain reliever. In a report by Bicher and Mechoulam (1968) they analyse the analgesic effect of marijuana. Using the hot plate test and the tail flick tests, Bicher concluded that the effective dose curve of Delta-9 THC was comparable to morphine. There were variances between the rats and the mice in the results obtained, but these are attributed to the different methods of administration. Another interesting thing was that THC had a longer duration of action than morphine and had a slower drug concentration peak. In 1999 Chichewizc and Welch found that Delta-9 THC induced analgesia in both vehicle treated and morphine tolerant mice. In both groups, analgesia was equally effective "indicating that analgesia produced by the combination is not hampered by existing morphine treatment" (i.e. no cross tolerance). Mice were injected with Delta-9 THC and morphine twice daily for 6.5 days and tested for tolerance on day 8. There was a tolerance for THC, but morphine tolerance did not occur. These results suggest low-dose combinations of THC and morphine might prevent or lessen morphine tolerance. This might be very useful in patients with chronic pain or with patients that need morphine for a considerable amount of time. Opiate tolerance is a problem that is faced in patients with chronic pain. In fact repeated opiate administration actually increases pain sensitivity for a period of 1 to 3 days after administration. To use an opiate and Delta-9 THC concurrently would lessen the tolerance effect and allow for better pain management. Another interesting study by Fride and Mechoulam (1993) found that anandamide produces analgesia. The first endogenous cannabinoid to be discovered, its full name is way to complicated to pronounce, arachidonylethanolamine. Named from the Sanskrit word ananda, which means bliss. Compared with THC, anandamide has only moderate affinity for the CB1 receptors and is rapidly metabolized. This means that its has to be used in sufficient quantities for effective stimulation of the CB1 receptor and it has a short duration of action. However it shares the majority of its pharmacological effects of THC. This rapid degradation of anandamide is similar to other neurotransmitters such as AcH and dopamine. But it creates problems when trying to study the effectiveness and might explain why studies with anandamide injected into the brain have different results.

With the isolation of the cannabinoid receptors, many new properties of the receptor system were discovered. Musty (1985) found that CBD, which is a single isolated cannabinoid, to have anxiolytic effects. The lick suppression test is a procedure in which thirsty rats are administered an electric shock after each 20th lick on a water spout. This results in a decrease in the number of licks made during the test session. Anxiolytic compounds increase the number of licks. CBD was found to increase licking for water. The interesting thing is that equivalent effects are found with diazepam, a drug regularly used for anxiety. In another series of experiments (Guimaraes1990) Used a elevated plus maze. In the first test, rats are placed in a plus shaped maze which is raised off the floor. Two of the maze arms are enclosed with walls and two are not. Time spent in the enclosed areas is taken as a measure of anxiety or fear. CBD and diazepam have similar effects, both decreasing