I don't want to stick to any specific view points but the idea of a chemical imbalance causing depression is just as much a theory as anything else, actual recent research has shown that a large percentage of people benefited better with CBT therapy alone, among many other things it also showed that medication did not do much in terms of changing mood for a lot of cases. It stated that a large percentage of people had benefited as a placebo about 40%. The thought that they are doing something to fix the problem drops it from their mind and then they persuade others about how amazing x,y,z drug is.. Then you are swarmed with slick and seductive ads from drug pharms showing people suddenly shifting one end to the other. If someone is suffering and you tell them its a chemical imbalance, they seek medication and feel no relief they can start to feel pretty hopeless and then they make an identity out of it which can make the depression come more out of force of belief system alone.. Symptoms are no doubt very real, and very physical but if someone really does the investigation themselves they will find its just a belief in some form of thought processing, the thought comes, then the feeling, then another thought.. If you are not aware of what is going on and are just riding out the process then you will not know where it started and will just seek external help or some relief elsewhere. It is a downward spiral in that sense because a person can identify and stick with a very, very distorted thought that can cause them to become suicidal even because they can't live with their own mind.. It is not that they want physical death as much as they can't live with an illusive sense of self or usually they would say they just want to dissapear, stop being me, etc.. This is all concentrated as a stem in ego and definitely without a doubt can be seen through as an illusion. I know people such as Bryon Katie or Eckhart Tolle, both who suffered for over 10 years and were extremely depressed and suicidal.. However now they are both free of suffering and stated the same thing, it was the belief in the thoughts that caused suffering, or the "little me". Bryon Katie offers a book called The Work, which is a self inquiry to break away from thoughts and feelings a person is identified with, showing them how they are deceiving themselves and a way to see it through. IF we are to state and tell someone they are suffering from a chemical imbalance and they need certain medication to control symptoms we are stating something we don't know for sure, and they can end up re instating that little sense of "Me" and possibly causing them unnecessary suffering.
Of course its not as simple as read this pick me up line, find meaning, go do this or that activity.. It takes time to overcome physical symptoms and behavioral habits do not change overnight. However a person can be shown a way that opens the opportunity to suffer consciously and to stop re in forcing the little "me". In this way the suffering that is caused by ego ends up burning up the ego itself.
CBT therapy if done correctly can break a person of their false thoughts and absolve the negative emotions that eventually become very intense and physical along with it. Of course there is nothing wrong with using medication along side CBT but its been shown also that some people are three times MORE likely to commit suicide from taking medication which would probably be the last thing a person should suggest to someone already feeling suicidal. In fact feeling suicidal is not even a bad thing, it just needs to be seen as that which wants to die is not who a person really is, a re direction of the question what wants to die can go much better then acting and fear and judgement of that person. There is also the toxic profile effects of medication, this is not the 70s anymore we have come a long way in regards to finding the root of suffering and how to eliminate it, which in some cases can be chemical such as severe bi polar, or schizophrenic but even in those times a person can work on overcoming them in the short term or when symptoms start to surface with medication and work on lowering dosages if they feel they can be stable enough.
One more thing that is misinterpreted alot is a feeling of emptiness inside, drying up of personal drive to do anything, a feeling of nothing ness.. The feeling of nothing ness or emptiness is not a bad thing at all, it can only get mis translated and interpreted in the mind as a sort of despair. If you get right down to it and strip someone of false identities there is nothing there, they literally are nothing in the core of their being, however they are also everything at the same time and not separate or lesser then a single thing else, the feeling of emptiness and nothing ness is actually a very nice and liberating feeling, it is the end of becoming this and that, no more self image and illusive sense of self to attack and defend, that mind is a liberated mind, and you don't experience absolute nothingness without the simultaneous everything ness, you can get a feel of nothing inside but that is just coming into your own true self which means a faceless voiceless death to a conditioned sense of self .. When a person goes into hypnosis of body and mind they wrap themselves up solely in self image and personality and its no wonder they feel depressed or anxious, the sense of isolation can become quite apparent when a person is left too long with their own thoughts and a turning away from there own being.
There does not have to be belief in anything just the opportunity to drop belief entirely and to experience what is actually real and true for yourself. Anyways I know I went on a rant, some of it more spiritual and the other part just a view on CBT.. I branched off into the spiritual because from my own experience it is what I actually know to be real and true, and if someone else has a flash of recognition they can see it for themselves.. On the other hand just wanted to talk about the benefits of traditional CBT and the reminder that this chemical imbalance thing is just a theory though harder to describe as such when you have billions of dollars invested into it and so much lucrative opportunity for pharm. However if someone is taking medication and they feel its working and they feel good all the more for them, this is just for the people that want to go a different route of investigation there is nothing wrong with either way.