As a trained pharmacist, the previous pharmacist is wrong in their interpretation and in their explanation. Specifically the way they explain the duration and

As a trained pharmacist, the previous pharmacist is wrong in their interpretation and in their explanation. Specifically the way they explain the duration and mechanisms of the drugs is incorrect. While the main focus of discussion tends to center around the “serotonin” aspect of SSRIs, this is akin to discussing a road trip and only talking about turning the ignition before you leave the drive way. Serotonin receptors in the prefrontal cortex are the beginning of the signaling pathways that are to a greater extent controlled by glutamate, nmda receptors, and GABA. Not to be forgotten are also the dopamine and epi/norepi. All of which are affected downstream from the initial signaling of 5ht1a/b and 5ht2a receptors. Changes in concentrations of these neurotransmitters, their receptors, and reuptake vesicles, lead to system level changes in mood and behavior. The idea that some “small changes” in serotonin levels for a few weeks is all that occurs with an SSRI is just plain incorrect. The resulting fluctuations from baseline in neurotransmitters and receptors translate to slow changes in plasticity and “direction” as pathways are reshaped. Depression stems from a “negative cognitive bias” that deepens and is self-reinforcing over time. Changing that bias by reshaping pathways takes time. For some people, a very long time, and for others (arguably most) the drugs alone cannot accomplish this change in direction toward s more positive cognitive bias without cognitive behavioral therapy, rebuilding social support systems, and a change of environment. It’s true that everyone has different chemical concentrations, different levels of enzymes for breaking down neurotransmitters, and differences in receptor availability and that has been reduced to an idea of “chemical imbalance” which is not only too simplistic but also it treats a person like a baking recipe that would be turn out well with just more baking powder. That PharmD in the comment did the same kind of reduction here. At a molecular level, permanent changes absolutely can and do happen. That is essentially what the mechanisms at work in ketamine therapy have demonstrated providing strong evidence for thr neuro plastic theory of depression.