Cannabis has a physical component in it's addiction or dependency pattern, whatever linguistic treats suits you because it messes with dopamine release. Affecting the dopamine release mechanism in your brain is a pretty physical concept, and that's what THC does. It connects to receptors mostly termed
CB1 and
CB2, where the first is located mostly in the brain(to a less extent lungs liver and kidneys) and the second in immune system cells(reason why cannabis generally makes your immune system weaker on one hand but more active on the other).
The physical process triggered by THC is still not entirely known but is very complex:
Regardless, the THC does a similar action to Anandamide which is the neurotransmiter available in our body naturally. Anyone who says THC is alright because we have a receptor for it, no we do not. It is an agonist for the CB1 receptors, because it shares part of the same molecular structure as Anandamide, but its not an exact replacement for it and the effects are very different as THC will have far more intense effects than anandamide. A few years back we had the RC crisis where people synthetized more agonists for this receptors based on THC and some had awful effects, research if curious.
The primary psychoactive ingredient of marijuana, Δ9-tetrahydrocannabinol (Δ9-THC), has medicinal value but also produces unwanted deleterious effects on cognitive function, promoting the search for improved cannabinergic therapeutics. The present ...
www.ncbi.nlm.nih.gov
As a result of the singalling process described above, THC will cause your neurons to release dopamine. Dopamine controls many processes in your body, particularly related to learning, habit forming and as consequence addiction. This happens because it's responsible for the reward response. Anything that messes with dopamine is by nature addictive.
The hypothesis that dopamine is important for reward has been proposed in a number of forms, each of which has been challenged. Normally, rewarding stimuli such as food, water, lateral hypothalamic brain stimulation and several drugs of abuse become ineffective as rewards in animals given...
www.nature.com
The consistent use of a substance that causes dopamine release(ignoring everything else for now) causes without a doubt the dopamine system to work differently and this is what's believed to be responsible for cannabis addiction(follow references in the article below), which by consequence is very physical:
Δ9-tetrahydrocannabinol (THC), the main psychoactive ingredient in cannabis, is a pressing concern to global mental health. Patterns of use are changing drastically due to legalisation, availability of synthetic analogues (‘spice’), cannavaping and ...
www.ncbi.nlm.nih.gov
For anecdotal verification of all this, it's pretty simple. If you are a heavy user, stop consuming and you will find yourself having withdrawal symptoms, most people do at least. Cannabis withdrawal has even been integrated into DSM V problem since 2013 and CRT has been proposed as a way to deal with it, because some patients consistently relapse into cannabis consumption due to the persisting withdrawal symptoms:
Cannabis is a common recreational drug that is generally considered to have low addictive potential. However, an increasing number of cannabis users are seeking treatment for dependence on the drug. There is interest in using agonist (substitution) pharmacotherapies to treat cannabis dependence...
pubmed.ncbi.nlm.nih.gov
All in all, scientific evidence aside, experience with addictive substances is enough to understand the symptoms of addiction and they're generally quite easy to recognize. If you feel like you have to justify the use of a drug, or that you need to give character or essence to a drug, then you need to re-assess how dependant you are on it.
Cannabis is a bundle of many substances, most of which we do not know the effects of. We have lots evidence on harmful effects, some evidence on a few positive effects and some indicators on possible beneficial effects. Cannabis extracts in the form of marinol and dronabinol are given to patients as confirmed treatments for problems nowadays in most countries. Many countries do recognize the medicinal value of cannabis but still do not allow for recreative use due to the evidence regarding the lack of safety of it's use.
I consume cannabis because it makes me feel good. It's the same reason as I'd consume any other recreative drug. Some people have found therapeutic value in the effects of it, and use it as aid for sleep, pain management, appetite management, etc... These people generally do so at their own risk and based on the for now unfounded belief that it is better than an over the counter replacement. Studies have yet to compare the efficiency of the given cannabinoid with the currently used medicines.
Cannabis like any other drug, be it a pharmaceutical drug or not will have a long list of side effects and as such awareness of this is key.
I never understood why some people worship cannabis as if it was a goddess. But I found this extremely curious and even came to have related discussions regarding whether the expression of this feeling in human use has not been an evolutionary step taken by the plant to ensure it's survival.
I love feeling high, but then most recreational drugs are lovable. Doesn't mean they're healthy. Doesn't mean they're anything other than a series of random molecules that happen to trigger certain biological processes.