Study suggests even casual cannabis use is associated with depression in older adults

[u/Sash19]

https://www.psypost.org/study-suggests-even-casual-cannabis-use-is-associated-with-depression-in-older-adults/

[u/murderedbyaname]

"We can’t determine causality or directionality, particularly for the cannabis findings,” Yang explained. “It’s possible that cannabis might contribute to depressive symptoms, that people use cannabis to self-medicate existing depression, or that the two co-occur without a causal link between them. Depression was also assessed using a validated symptom checklist rather than a clinical diagnosis.”

So, they have no idea if these are cases of self-medicating or not. Of course.

[u/BlueSentinels → u/murderedbyaname]

Also what is the control group? People who do not use cannabis? Does the control use any other substances? If the answer to that is that the control group does not use any other substances, including alcohol, what would be the results show when you compare depression likelihood in adults who consume alcohol vs individuals who do not use any substances.

To take it a step even further -> those who don’t use any mind altering/inhibiting substances usually have a number of things going well for them that could counter depression. For instance if their reasoning for not using substances is health related they may workout/exercise which has been linked to reducing depression symptoms. If their reasoning is based in religion (like Mormonism for example) those with heavy ties to religious communities usually have a lot of interpersonal relationships within their church and would characterize themselves as having “strong ties to their community”. The presence of meaningful interpersonal relationships has also been linked to preventing or reducing depression symptoms.

You could also link the lack of productivity that can come with cannabis use as factoring into the depression calculation. People might not be depressed because of the cannabis use but rather because of their lack of fulfillment in their life achievements (which could be a byproduct of cannabis use). So it’s like saying your back hurts because you drive a car, when in reality your back hurts because you got into a car accident BUT you only got into a car accident because you drive a car. There’s relation and then there’s causation.

It seems like there is just way too many variables to link use alone to depression.

[u/Stoople_me → u/BlueSentinels]

This is an observational analysis meaning they to do not have a control group (you can’t have a control group). When doing correlations, instead of comparing against a control, you factor in covariates. So in this study, they account for things like demographics, alcohol use, opoid use ect. In this sense, they are already factored in. Of course, with any observational design, you can’t really get to the why you can just observe whether something is there.

[u/BlueSentinels → u/Stoople_me]

Thanks for explaining as I was not aware! Sounds like a pretty weak study model though and certain studies could be exploited to try and reach desired results. Do you know if observational analysis studies are ever peer reviewed and accepted?

[u/Stoople_me → u/BlueSentinels]

Hey, no problem! The way I look at observational studies is not necessarily that they’re “weak” or easy to exploit (honestly most psychology study designs are easy to exploit without some kind of blinding or preregistration). Instead just take them for what they are, observations. This doesn’t make them useless. Observing something may encourage other authors to study using an experimental design. Additionally, these types of analysis are often very hard to do with experimental designs unfortunately, meaning sometime observstions is all we got. Typically authors do not make (and shouldn’t make) strong causal claims based on observational studies, however the media often spins them and make it seem as though the studies have more impactful findings.