Perhaps I might pause here from my account concerning Geraldine in my most recent blog; this in order to outline in greater detail a little more about chemically (or biogenically) induced depression. As it happens, we all – in the course of our regular metabolic processes – manufacture and supply to body and brain, a chemical compound known as “serotonin” which essentially is involved in normal everyday functioning. In point of fact, serotonin is closely related to the amino acid, tryptophan (which is particularly prevalent in milk and carbohydrates) and which in turn is an essential component of protein.
Serotonin is present in numerous organs of the body and, among other functions, is involved in the constriction of small blood vessels and the elevation of blood pressure. A crucial one per cent of its supply is to be found in the brain, where it performs the role of a neurotransmitter (chemical messenger) and is especially implicated in the regulation of mood and sleep. Other impressive research has further hypothesized that serotonin actually cools the brain, (which makes perfect sense of use of the descriptive term in common parlance; “cool-/hot-headed” does it not?)
When depleted, i.e. where there is an insufficiency, normal functioning (in terms of mood and the feeling of well-being) is increasingly adversely affected. This shows itself emotionally and behaviourally in some or all of the classical and well-documented symptoms of chemically-induced clinical or major depression. These are, unremitting depressed mood and sadness experienced over a significant period (see below); reduced appetite, sleep disorder, feelings of worthlessness, loss of libido (sexual interest), loss of interest generally, poor concentration and memory, reduced energy levels, anxiety (not always present but where it is, commonly in the form of an anticipatory anxiety and agitation) and suicidal thoughts.
How then does this kind, i.e. chemically induced depression, differ from psychogenic or reactive depression? Well as we have already seen, in the first place it is ‘triggered’ differently. Psychogenic depression stems we said, from external events in everyday experience. It is a reaction to them; whereas chemical or biogenic depression is caused by a response to the depletion of the neurotransmitter serotonin and its premature withdrawal from key synaptic sites within the brain.
Also – and certainly in my own experience of this latter kind of depression in patients – there are two key symptoms which, taken together, amount to what many regard as its hallmark. These are i. unremitting, i.e. without let-up, “low mood” and sadness extending over several days into weeks and maybe longer and ii. What is sometimes referred to as, “anhedonia” (loss of pleasure) i.e. loss of that warm and vital response to even very simple things in life such as a nice cup of tea, the sight and scent of flowers in a garden, or the touch of a little child’s hand.
Cast your mind back if you will to my recent account about Stephen; although depressed to the point of urgently requiring expert help, Stephen was nevertheless (as his own account revealed) still able to enjoy, for example, “a sunrise”. Moreover, his mood did appear to lift from time to time, especially when visiting the meadow and sometimes when lying in bed beside his sleeping wife at night. By contrast, Geraldine summed it all up when she said, “it is as if someone around here has put out the light and withdrawn all the joy from living”.
(Continued in next week’s blog).