Brief Answer:
Cannabis can affect cognitive performance.

Detailed Answer:
Hello and thanks for your query.

Several studies have shown that cannabis can negatively impact cognitive performance and result in cognitive deficits.

There is no solid evidence that Cannabis causes any structural brain damage, but the impact is more subtle. Some of the well documented areas of cognitive performance that are affected by Cannabis are:
- Response time
- Visuo-spacial functions
- Verbal memory
- Executive functioning, etc.

The important thing many users ignore is the fact that these deficits happen very subtly and over a prolonged period of time. So, since the changes are not dramatic, most persons fail to notice them clearly.

The second important thing to realise is that these cognitive effects are very variable in presentation. There may be a few persons who may not manifest any prominent cognitive decline, whereas some others may get impacted quite negatively.

The third point is that some people argue that these cognitive deficits have been documented only in high users and long term users and that it may be not be harmful to take a few puffs once in a while. But the point is we don't know who will get hooked on and become dependent and who will not (but we know for sure that cannabis has a high "risk" for dependence)

So, in my opinion, when we know that there is a "risk" of cognitive impairment due to cannabis, it may not be worthwhile to take the risk and wonder how prominent the effects are going to be. You may never know how it turns out to be...

To explain this concept of "risk", I would like to give you a small example. It's like overspeeding on the road. Now, we know that many people overspeed and still don't get into an accident. Few who overspeed and meet with an accident can still escape with no major injuries. But this doesn't mean that there is no "risk" if you overspeed. Because it is a well-proven fact that people who overspeed on the road are definitely at a "higher risk" of meeting with an accident and suffering serious injuries.

Hope this puts things in perspective...

Best wishes,
Dr. Jonas Sundarakumar MBBS., DPM., MRCPsych.(U.K.)
Consultant Psychiatrist

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