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Dr Sacrifice Chirisa Mental Health Matters
Delta-9-tetrahydro-cannabinol (THC) is the main psychoactive that is a mind-altering ingredient in marijuana and is responsible for the majority of the effects of using marijuana. THC is a highly lipid soluble, which means that it can cross the blood-brain barrier and reside in certain body tissues for extended periods of time up to 30 days. The central nervous system has endogenous receptors called cannabinoid receptors, which have high binding affinity towards THC.

When THC binds to the receptor, the receptor becomes activated and through second messenger actions -carried out by a molecular interaction separate from the initial THC/cannabinoid receptor binding – initiates a cascade of events that ultimately results in impaired cognition and altered mood.

When looking at heavy recreational marijuana use, there are adverse effects on cardiovascular health in some individuals, including the development of new onset arrhythmia and even heart attacks. Additionally, heavy and or long-term marijuana use can have negative effects on certain neurologic functions, and these consequences have been reportedly quite long term, if not irreversible. Cognitively, marijuana may diminish the user’s ability to:

• Reason.
• Use short-term memory
• Learn new tasks.

On a molecular level, marijuana affects the formation of new connections between neurons, which is essential to the cognitive tasks mentioned above.

Marijuana use at a young age, that is 18 years and below, is also correlated with episodes of psychosis later in life, and there has been historical mention in the literature of a possible “cannabis psychosis” that can accompany years of heavy use. The respiratory system may also be affected by marijuana abuse. Similar to tobacco smoke, marijuana smoke is a lung irritant and causes symptoms such as:

• Daily cough and phlegm production.
• Frequent lung illness.
• Chronic bronchitis.
• Increased risk of lung infection.

One of the problems with marijuana abuse and psychiatric illness is the poor response to treatment for the psychiatric illness. Typically, marijuana abuse is an indicator of a poor response to treatment in this population. Unfortunately, the chicken-and-egg paradigm applies here. Did the psychiatric illness come first, leading to marijuana use? Or did the marijuana use come first, precipitating an underlying psychiatric illness?

From my experience as a psychiatrist, the use of marijuana increases the incidents of mental disorder. The benefits of use versus the risk of problems are incomparable. True, not everybody who uses it will become ill but you do not know your risk level. The recent move is regrettable. We will help those who need our help and more people will need marijuana detox and rehab services.

Dr Sacrifice Chirisa is a passionate mental health specialist at Parirenyatwa Hospital, one of the country’s major referral centres