IS MARIJUANA ADDICTIVE?  


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Growing up in the sixties and seventies, I was aware of the ongoing debate on the addictive potential of marijuana.  The consensus was that it was psychologically addictive.  There was no evidence of physical dependency. 

However in the late seventies and eighties, a series of studies revealed that stopping the drug was associated with a consistent pattern of withdrawal symptoms.   These included sleeping irregularities, nausea and poor appetite, restlessness and irritability, depression and shakiness.  This could be seen in persons who used the drug daily for as little as three weeks.    It begins 10 hours after cessation of the drug.  It peaks in two days and is finished about 5 days later. 

The syndrome may be mild but it is significant enough to cause craving for the drug.  Many people tell me they are not addicted but use the marijuana to relax.  They do not have insight into the fact that
a mild degree of cannabis withdrawal is the reason that they are not relaxed.   Although most persons undergo a relatively short period of withdrawal, some have more prolonged and more severe symptoms.  On several occasions, I have seen co-existing anxiety symptoms spike and remain quite distressing for 6-8 weeks. 

Marijuana shares the properties of most other abused drugs in that it can increase dopamine activity in the brain.  This causes the euphoria and leads to addiction potential.    Experimental evidence shows a similarity in the effects of marijuana and opiates. It appears that THC, the active ingredient in marijuana, has specific receptors in the brain.  When these receptors are stimulated, they indirectly stimulate the opioid receptors in the brain.  We know that naloxone, a medication used to block the effects of heroin and other opiates, also blocks the effects of marijuana.  My belief is that the euphoria of marijuana is obtained via release of endorphins and stimulation of the opioid receptors.  

It seems likely that the withdrawal syndrome in marijuana is based on mechanisms similar to that of heroin withdrawal.  The increased opioid activity caused by THC may lead to a mild physical dependency.  Perhaps the withdrawal syndrome seen in marijuana is based on a reduction of opioid activity in the brain.  We know that the symptoms described in marijuana withdrawal above are present in opiate withdrawal.  Clonidine, used for opiate withdrawal, also has been found successful in blocking marijuana withdrawal.  It is for this reason that I comically label marijuana withdrawal as opiate-lite.  

Marijuana is also a good anti-depressant.  One study compared the incidence of depression in marijuana users to a population that had no addictions.  There was less depression.  Clearly, marijuana reduced depression which it can do through a series of different mechanisms.  However, when it wears off, we become more depressed.  Anxious people become more anxious

Marijuana has historically been seen as a completely safe drug.  Its withdrawal is relatively mild.  However, just because we are not doubled up in pain, does not mean we are not uncomfortable.  It only takes a little discomfort to motivate us to continue using especially if do not realize that the marijuana withdrawal is contributing to our discomfort

With the above information coupled with the fact that marijuana today has been bred to be more potent then in the past, we need to realize that it is not as safe as once thought.   

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S Wasser MD May 9, 1997   Revised February 27, 2006