Marijuana Effects


1.  The two types of chemicals in the brain are neurotransmitters and hormones. Neurotransmitters are dopamine (found in the basal ganglia), acetylcholine (found in the parasympathetic branch in the cerebral cortex) and nor epinephrine. Endorphins are opiate like chemicals that occur naturally in the brain of humans and other animals.

2.  Specialized structures that recognize neurotransmitter molecules and cause a change in the electrical activity in the neuron when activated are receptors.

3.  The nervous system can be roughly divided into the central nervous system, autonomic system, and somatic system.

4.  Psychoactive drugs work by altering the availability of a neurotransmitter at the synapse and directly interacting with a neurotransmitter receptor.

5.  The branch of the autonomic system that stimulates digestion, slows the heart and has other effects associated with a relaxed physiological state is the parasympathetic system. 

6.  The central nervous system, brain, spinal cord and basal ganglia, or the cells of the brain that make up the gray matter, are responsible for maintaining muscle tone. Psychoactive drugs interfere with the proper functioning of the muscular system. 

7.  The energy requiring mechanism by which selected molecules are taken into cells is called uptake. This energy is needed so the cells that are making the neurotransmitter can absorb the precursors (chemicals needed to make the neurotransmitter) from the blood stream.


1.     Marijuana consists of the dried and crushed leaves, flowers, stems, and seeds of the Cannabis sativa plant.

2.     THC (delta-9-tetrahydrocannabinal) is the primary mind-altering ingredient in marijuana.

3.     Derivatives of the Cannabis Plant

a. Hashish: Avg. concentration of THC is 2% to 8%

b. Ganja: Consists of the dried tops of female plants

c. Sinsemilla : Avg. concentration of THC is 7.5%

d. Bhang: Avg. concentration of THC is 1% to 2%

4.     In 1926 a series of articles associating marijuana and crime appeared in a New Orleans newspaper.

5.     Thirty-six states had laws regulating the use, sale and/or possession of marijuana by 1935.

6.     Many laws were based on and developed because of popular literature linking marijuana to crime, not the effect of the drug.

a. Scientific American reported in 1939 that marijuana, when combined with intoxicants, makes the user have a desire to

    fight and kill.

b. Many newspaper reports were similarly blaming marijuana for killing and fighting.

c. The problem was that there was no medical evidence to support the relationship between marijuana  and crime.

7.     The Marijuana Tax Act of 1937 was passed without much debate.

a. It was a tax law so it did not outlaw marijuana - just taxed it.

b. One medical doctor testified against the bill because he felt the state’s anti-marijuana laws were adequate and that the

    social-menace case against cannabis had not been proven.

8.     THC was isolated and synthesized in 1964 and is clearly the most pharmacologically active.

a. THC is rapidly absorbed into the blood and distributed first to the brain.

b. Peak psychological and cardiovascular effects occur within 5 to 10 minutes but have a half life of 19 hours.

c. Physiological effects

                  i. Central Nervous System

                  ii. Cardiovascular System

                  iii. Respiratory System

                  iv. Sexual Performance and Reproduction

d. Behavioral effects:

                  i. Low to moderate doses produce euphoria and a pleasant state of relaxation.

                  ii. Common effects: dry mouth, elevated heartbeat, some loss of coordination and balance, slower reaction times,

                      reddening of the eyes, elevated blood pressure.

                  iii. A typical high lasts from 2-3 hours, and user experiences alter perception of pace and time, and impaired memory.

                  iv. An acute dose of cannabis can produce adverse reactions: mild anxiety to panic and paranoia.

                  v. A few rare cases exhibit psychoses, delusional and bizarre behavior, and hallucinations.

                  vi. These reactions occur most frequently in individuals who are under stress, anxious, depressed or borderline


e. Driving Performance

                  i. The ability to perform complex tasks, such as driving, is strongly impaired while under the influence of marijuana.

                  ii. Studies done in a lab, with non-regular marijuana users, show there are significant impairments.

                  iii. Studies done on drivers involved in car accidents show there is not an over-representation of marijuana use.

f. Critical Thinking Skills

                  i. Marijuana has been found to have a negative impact on critical thinking skills.

                  ii. Impairment can affect: attention, memory, learning.

                  iii. The unresolved question is whether these impairments are short-term or long-term.

9.     Medical Marijuana

a. Involves using the THC in cannabis as a drug to calm or relieve symptoms of an illness

                  i. Glaucoma

                      1. Potentially blinding eye disease causing continual and increasing intraocular pressure

                  ii. Marinol

                      1. Indicated for treatment of nausea and vomiting in cancer patients

                  iii. Anorexia in AIDS patients

                  iv. Antiasthmatic drug

                  v. Muscle relaxation

                  vi. Antiseizure effect

                  vii. Antidepressent

                  viii. Analgesic

                  ix. Appetite stimulant

10.   Negative effects of marijuana

a. Heavy marijuana smoking can decrease testosterone levels, diminished sperm counts and sperm structure can be


b. Lower birth weight and shorter length at birth are reported in mothers who smoked during pregnancy.  The problem

    is that most women who are smoking marijuana are also drinking and smoking tobacco during the pregnancy, so it is

    difficult to place blame solely on marijuana.

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