Updated 27 September 2018

Here’s why dagga can be dangerous if you have a mental disorder

More and more countries are now legalising the use of marijuana. Here's why dagga may be dangerous if you have a mental disorder.

Marijuana, known as dagga in South Africa, has been a controversial plant for a long time. On Tuesday 18 September 2018 News24 reported that the Constitutional Court has ruled that it is legal to be in possession of dagga in your private capacity.  

There are strong arguments, both for and against the legalisation of dagga. While it may help some, it has adverse effects on others. We explore why dagga is dangerous if you have a mental disorder.

So what are the effects?

Marijuana is made up of a number of chemicals called cannabinoids. The main ingredients found in cannabinoids are tetrahydrocannabinol (THC) and cannabidiol (CBD). Maja Kwiatkowski, clinical psychologist for Nurture Harmony Recovery and Wellness facility in Hout Bay, describes THC, the chemical responsible for producing the “high”, as a “psychoactive component”.

Professor Wayne Hall, a researcher at the Centre for Youth Substance Abuse Research (CYSAR) at the University of Queensland, said in a study that, "THC may cause anxiety and psychotic behaviours in users." Kwiatkowski told Health 24, "This is due to various factors such as one’s genetics, medical/psychiatric history, the frequency of use and the amount of marijuana used." People with mental disorders are therefore at risk of worsening the state of their disorders.

Research shows that cannabis use is linked to depression, bipolar disorder and schizophrenia. The argument linking cannabis to depression is not strong, however. Many studies show that people who suffer from depression use cannabis. Whether cannabis causes depression or depression leads to patients using cannabis to cope with the disorder is unclear.

In a study conducted by the National Drug and Alcohol Research Centre, it was argued that THC affects one’s neurotransmitters and serotonin levels, thus creating depressive symptoms. Using marijuana does put you at risk of damaging your cognitive function. However, it has been found that people with depression often use marijuana as a form of self-medication. THC’s psychoactive components can lead to states of euphoria and relaxation.

Dr Michael West told Health 24 that, "In some studies involving people with bipolar disorder, cannabis use is associated with more frequent periods of illness, and shorter periods of wellness between episodes. The conditions where cannabis appears most harmful are the schizophrenia-spectrum disorders and bipolar disorder. There appears to be a mixed effect on unipolar depression and anxiety with some patients reporting symptom improvement, others symptom worsening and others reporting no effect at all."

Schizophrenia trigger

Over a 15-year period, a number of Swedish conscripts who had used marijuana by the age of 18, were found to be 2.4 times more likely to be diagnosed with schizophrenia. The study found that had the conscripts avoided using marijuana, 13% of those diagnosed with schizophrenia could have avoided the diagnosis.

But this science is not set in stone. Dr Michael Niss, a psychologist from The Foundation Clinic, based in Johannesburg told Health 24, "The argument for marijuana causing schizophrenia is not convincing... but marijuana has mind-altering capabilities." THC reacts with the CB1 and CB2 receptors in the body. The CB1 receptor can be found throughout the brain and is thus involved in cognition, motor coordination and memory reward. The CB2 receptor can be found within the immune system and thus explains the pain alleviation effects of THC.

Many experts agree that similar to medication, marijuana has varying effects on people. So while the science is not absolutely clear, it is advisable for people with mental disorders to steer clear of using marijuana. 

Image credit: iStock


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