Possible Brain Shrinkage Expands Health Concerns About Marijuana Abuse

Alexa and her new friends would come back to her house after school, laughing and giddy. They would raid the kitchen, grabbing snacks and drinks before heading upstairs to her room. Mom heard the laughter and was happy that Alexa had such good friends that had fun together.

This pattern continued for a few weeks, and Mom noticed that Alexa was gaining a bit of weight. She wasn’t concerned, as Alexa had often put on extra pounds before a growth spurt. As a young teen, both her body and her brain were still growing and developing. The giddiness and laughter were probably just normal teenage silliness, thought Mom. But it still seemed a bit unusual that they didn’t talk about it, considering their close family relationship.

Problems were beginning to surface. Now when Alexa wasn’t upstairs giggling with her friends, she was often sullen and withdrawn. Mom wondered about the uncharacteristic moodiness. And Alexa wasn’t coming home as regularly as she always had in the past. She was spending far too much time with her new friends, and her grades were dropping. Mom had a nagging feeling that something was wrong, but she couldn’t quite determine what. Family relationship problems had never been an issue before now.

She tried to talk to her daughter, but it was always a frustrating one-way conversation. She quit trying. Alexa wasn’t interested in talking with her mom anyway, except when she was asking for more money again. Mom wondered what she was spending the money on and how she was spending her time. She remembered the past joy of sitting on Alexa’s bed after tucking her in, talking about the day and their dreams. She longed to return to those times. She wanted her daughter back.

One evening, the phone rang. It was a neighbor, Kylie’s mom, saying she had found Kylie and Alexa smoking pot with their friends near the park. Mom just sat there, wiping the tears as she asked herself how she could have missed the warning signs. When the shock wore off, she gathered and read as many articles on cannabis (marijuana, pot, weed) as she could find. Although it was difficult, Mom insisted that they talk that night. They talked about the importance and responsibility of taking care of one’s body and brain. They talked about how Alexa’s actions had hurt their family relationship. “Problems with marijuana? Nah. It’s not even addictive,” said Alexa as she tried to convince her mom that smoking pot wasn’t a big deal. “I can quit anytime, and it’s really not bad for you.” Fortunately, her mother was forearmed with results from the latest studies, and she kept talking. For days, Mom took every opportunity to talk with her daughter. Slowly Alexa began to see that those she thought were her friends had given her some dangerously bad information.

Alexa was not alone in believing that marijuana abuse is not a serious threat to health. Many in the past have shared her misconception. However, through news articles and surveys in recent months the Western world has been reminded that marijuana use is harmful. Yet as one report from Australia concludes, “translating this knowledge into behavioural change [is] a major challenge.”

Studies from around the world give more reasons to avoid recreational use of marijuana. A health news article in the June 2008 Archives of General Psychiatry outlines the results of an Australian study on regional brain abnormalities associated with long-term heavy cannabis use, including reduced volumetric measurement of the hippocampus (12 percent) and the amygdala (7.1 percent). While there is little universal agreement on what constitutes heavy smoking, the subjects in this study smoked an average of 5 marijuana cigarettes per day for nearly a 20-year period.

The hippocampus and the amygdala both reside deep within the brain in the temporal lobe. The hippocampus is related to emotion and is responsible for recent memory. Its shrinkage is associated with schizophrenia and sometimes with severe depression. The learning and memory difficulties associated with Alzheimer’s disease are a result of shrinkage and damage to the hippocampus; older, established memories remain but new memories are fleeting, making learning new names or remembering to turn off the stove much more difficult than remembering the name of one’s second-grade teacher.

The amygdala, located to the front of the hippocampus, is the almond-shaped cluster of neurons that, like the hippocampus, is related to emotion and memory. Amygdalae are also involved with regulating fear, anxiety, aggression, and pleasure. Shrunken amygdalae are associated with impaired social behavior and autism spectrum disorders.

Understanding the harm marijuana can cause is a good incentive for quitting, but many users have a difficult time doing so despite the risk to their bodies and their brains. Recent studies indicate that withdrawal symptoms, both physical and psychological, are very real for many who try to quit, and they find it easier just to surrender and start using again. Such symptoms can include irritability, anxiety, depression, boredom, appetite changes, nausea and stomach upset. However, one nearly immediate benefit of quitting is increasingly improved memory for many.

Alexa decided to quit and noticed that her memory improved soon afterward. She did have one relapse, but she was soon able to stop using marijuana completely with help and support from her family. Relationship problems, which began with her increased use of marijuana, improved dramatically. Alexa has been clean for over a year now and is doing well in school again. Her future looks promising.

Alexa’s story (which is a compilation of several real stories involving real teens) had a happy ending. It seems she was able to quit before she caused serious damage to her health. But her story would have been happier if she had never started at all. We each have a responsibility to take care of our own bodies and our own brains, and understanding the health issues should dissuade us from abusing ourselves by abusing marijuana.