Your brain on cannabis

A recent article in the Irish Times exploring how a new, highly potent strain of cannabis now being grown in Ireland is more harmful than the drug’s benign image would suggest, prompted me to write about the topic this week.

Marijuana can hurt you

The marijuana problem is much bigger than previously recognized. It is the most widely used illicit drug in the world. Of the 5.6 million people suffering in the US, 62% are using marijuana and young people – some now as young as 12 years of age – represent 23% of the suffering population. The average age of initiation is decreasing while marijuana’s potency is increasing. With increasing potency and earlier use, marijuana poses a significant threat. It is no surprise then that of all teens in drug treatment, 62% have primary marijuana diagnosis. That number represents more young people in treatment than for alcohol and almost equal to the numbers from criminal justice and other sources

Route of administration

Marijuana (from the Mexican Spanish marihuana) also known as cannabis, is much more powerful today than it was 30 years ago. Marijuana is the herbal form of cannabis, and comprises the flowers, leaves and stalks of the mature female plant while hashish is the resinous, concentrated form of cannabis. Chemically, the major psychoactive compound in marijuana is Delta-9-tetrahydrocannabinol (Δ9-THC); it is one of 400 compounds in the plant The smoke also contains more than 150 other types of these cannabinoids such as cannabidiol (CBD), cannabinol (CBN), and tetrhydrocannabivarin (THCV), which can produce sensory effects unlike the psychoactive effects of THC. The pharmacology of marijuana is complex. The cannabinoids are vaporized (smoke) and then deeply inhaled. They are fatty compounds which rapidly cross from the lungs into the blood and tend to accumulate in specific regions of brain.

The psychological effects of marijuana – a Pandora’s Box

The immediate (acute) effects of marijuana include changes in time-sense, a loss of recent memory and impairment in attention. There is also a general difficulty expressing simple thoughts in words. Other effects include impaired motor skills, increase in hunger, nausea, dizziness, and  – depending on the personality of the person and the context in which it is taken – altered moods such as euphoria, a state of relaxation, panic, anxiety, tension, anger, confusion and – especially when eaten – an unpleasant sensation called depersonalization.

The effects on your body are not good either

Marijuana smoke contains more than 150 compounds many of which are cancer–causing so the respiratory system including the lungs suffer the most. Common symptoms include air obstruction, chronic cough, bronchitis, decreased tolerance to exercise and cancer. An increase in heart rate can aggravate existing cardiac conditions or high blood pressure (hypertension) – so don’t take this drug if you have a weak heart.

Definitely not good for your MOJO

Marijuana decreases blood testosterone levels, sperm count and motility. It also decreases sex-drive (libido) and impairs fertility as well as disrupting the female reproductive system which can impact pregnancy in adverse ways. The effect of the drug on the immune system is still unclear but recent studies in animals demonstrate that it impairs T helper cells – key cells in the immune system – which may increase the risk of cancer (by disrupting the cancer surveillance system).

In Part Two of Your Brain On Cannabis, we will take a closer look at the effects of marijuana on your brain, how the drug affects how you learn, how to counter the argument that it is a harmless drug, and if there is any scientific basis for using marijuana as medicine.

Weekly Round Up

Image Source: The Dana Foundation

Our senses of sight and hearing work closely together, perhaps more than people realize, a new UCLA psychology study shows.

A team of neurobiologists  has shown for the first time that cortex, the largest area of the brain that is typically associated with higher functions such as perception and cognition, is also a prominent site of emotional learning.

Tiny electric currents applied across regions of the brain can improve hand movements in recovering stroke patients for a short period, an Oxford University study has demonstrated.

For the first time, scientists have proven that cannabis harms the brain. But the same study challenges previously-held assumptions about use of the drug, showing that some brain irregularities predate drug use.

How might keeping patients awake during surgery lead to the more successful removal of brain tumours? James Keidel, in his shortlisted entry for the 2011 Wellcome Trust Science Writing Prize, explains.

Researchers from the University of Bristol have discovered that a chemical compound in the brain can weaken the synaptic connections between neurons in a region of the brain important for the formation of long-term memories. The findings, published in the Journal of Neuroscience, may also provide a potential explanation for the loss of memory associated with Alzheimer’s.