Hi Ang
Below is a scientific explanation of how citalopram works.
I thought that it may be useful to you when you see the person who is treating you for your depression, even though you may find the information too technical.
A lot of the information below is from scientific sources that I have researched and referenced, though some of what I have written is my personal experience of citalopram:
Mode of action of citalopram, an SSRI
‘Depression is characterised by an over activity of the hypothalamic-pituitary-adrenal (HPA) axis.’
http://www.neuroendo.org.uk/content/view/31/11/
Two significant symptoms of clinical depression in many patients are insomnia and anxiety. These symptoms are therefore the result of an overactive HPA axis in the brain. The administration of an SSRI will, initially, stimulate this HPA axis further, before the SSRI suppresses the HPA axis at the pituitary level:
‘Acute citalopram activated the HPA-axis at the hypothalamic level and long-term citalopram treatment desentised the HPA-axis at the pituitary level’
Ref: Journal of Neuroendocrinology Volume 11 Issue 6 Page 465-471, June 1999
Citalopram, by stimulating the HPA axis, causes the release of ACTH (Adrenocorticotrophic hormone). This, in turn, stimulates the adrenal cortex, causing the release of cortisol into the bloodstream:
‘…Intravenous administration of the selective serotonin (5-HT) re-uptake inhibitor, citalopram, increases plasma cortisol.’
Ref: Journal of Psychopharmacology Volume 163 Number 1 August 2002
http://www.springerlink.com/content/6x9tne5ml1nlad33/
Consequently, clinically depressed patients, who are already experiencing insomnia and anxiety, will sleep even less, feel more anxiety and may begin to have panic attacks as they are placed in an even more intense ‘fight and flight’ state by ingesting citalopram:
‘Although stress isn’t the only reason that cortisol is secreted into the bloodstream, it has been termed “the stress hormone” because it’s also secreted in higher levels during the body’s ‘fight or flight’ response to stress, and is responsible for several stress-related changes in the body.’
http://stress.about.com/od/stresshealth/a/cortisol.htm
I took citalopram for 7 weeks and during that time I experienced continuous anxiety, many panic attacks and very severe insomnia, with only limited relief of my low mood.
Whilst taking citalopram I was given zopiclone to relieve my insomnia. Zopiclone is a hypnotic and can only be taken continuously for 4 weeks or on 28 separate occasions, as it is addictive. I was advised to take the zopiclone infrequently and not continuously, so took it every third night. On the occasions I did not take it I experienced many nights when I did not sleep at all, only falling asleep for a couple of hours around 6-7 am in the morning.
Some medical practitioners prescribe propranolol, a beta blocker, for their patients when they start taking citalopram, to slow the heart rate during a panic attack.
When citalopram is discountinued and the HPA axis is no longer suppressed, more ACTH will be released from the pituitary gland and the adrenal cortex will therefore release more cortisol. Consequently, many patients have withdrawal symptoms when they stop their citalopram medication, possibly experiencing, again, anxiety/panic attacks and severe insomnia.
‘Withdrawal symptoms when treatment is discontinued are common, particularly if discontinuation is abrupt (see section 4.8 Undesirable effects). In clinical trials adverse events seen on treatment discontinuation occurred in approximately 40% of patients treated with citalopram.’
http://emc.medicines.org.uk/emc/assets/c/html/displaydoc.asp?documentid=1070