It's worth noting that although there are neurochemical and synaptic differences in individuals with depression and individuals without, the vast majority of th

It's worth noting that although there are neurochemical and synaptic differences in individuals with depression and individuals without, the vast majority of the time it's due to environmental factors from chronic, long-term stress and unhappiness. There is no evidence to suggest any form of "chemical imbalance" happens from birth, or is lifelong, on a large scale. Therapy, building a positive social support group, and proper sleep, diet, and exercise are just as likely to "fix the chemical imbalance" as antidepressants. The chemical imbalance idea is an oversimplification of what is going on. There is evidence that giving a serotonin agonist helps symptoms of depression, giving a dopamine agonist helps ADHD symptoms, a dopamine antagonist helps with some symptoms of schizophrenia, etc. Therefore, you want to conclude that if blocking (or increasing) a neurotransmitter relieves symptoms, that the person did not have the right levels of the neurotransmitter in the first place, thus, a chemical imbalance. The problem with this idea is that simply changing the levels of a neurotransmitter does not necessarily cause a clinical effect. Take depression, once you start taking an SSRI, your serotonin levels start to increase right away, but you will not see the mood enhancing effects for a couple of weeks. This is likely because there are issues with serotonin receptors, and the flood of extra serotonin helps to reset them. For schizophrenia, if too much dopamine was the answer, we would expect to see increases in its metabolites, but we do not. More likely, there is a problem in the pathway that projects dopamine from the midbrain to the forebrain, which causes it to not function properly as negative feedback, therefore allowing over-activity of dopamine pathways from the midbrain to the limbic areas. I personally believe this is why many invidivuals report post-trip lessening of depression or anxiety, cessation of smoking or other addictive behaviors such as gambling, and even improvement of cluster personality disorders symptoms in some cases. It's not an inherent neurological trait, but a complex interaction in the way that you view the self and society. Psychedelics allow people to view situations and experiences in a way they've never viewed them before, and in a way this is giving a key to a perspective that they've never heard before but resonates deeply with them, helping to initiate serious change.