ONLINE CONSULTATION: the doctor's next topic is the related wider aspects of depression and therapy. For how to e-mail your question for answer online on Wednesday and to read other recent topics click here.

Note from Dr Stuttaford: As usual we will try and answer all the points raised, but will have to do so in general terms as unlike our reader's doctors I haven't had the advantage of meeting the writer and don't know all the factors that influenced any medical decision.

I am 35 and have suffered from bouts of depression for many years. During both pregnancies I was very depressed and took no medication. The depression lifted away after each baby was born. Since my periods started again last year I have had several low points each month but in no obvious pattern. Last month I felt really bad and started taking Sertraline as I am still breast feeding my 20 month old. I had an unusually long cycle and then an unusually short cycle leading me to believe that my depression is hormone related and if so, are anti depressants the best treatment? I very much dislike taking them). We have avoided doing anything to regulate my periods such as having a coil or taking the pill since I seem to be sensitive to the pregnancy hormones.

I am keen to continue breastfeeding but am worried that it would be better not to even though they are supposed to be safe. Is there such a thing as hormone related intermittant depression and if so is there an alternative treatment? Would it be best to stop breastfeeding since it isn’t really necessary now she is older? Does reducing her feeds and delaying feeds help at all other than making me feel better? Name and address withheld

The antidepressant Sertraline, a 5HT reuptake inhibitor, was originally marketed under the brand name Lustral by Pfizer. It has a profile very similar to that of Prozac, and is a well tried and trusted drug. Sertraline has proved especially useful in treating depression that is associated with such conditions as pre-menstrual tension. It is also useful when the anxiety component of the depressive illness is predominant, as in obsessive compulsive disorders, post traumatic stress disorder and social phobias. In all cases of clinical depression the patient has some degree of anxiety, as well as the other depressive symptoms. The amount that anxiety contributes to the overall picture varies from case to case. In general SSRIs (5HT re-uptake inhibitors) are better tolerated than the older antidepressants, but it is important to make certain that liver and kidney function is, and remains, normal.

Whereas it is known that some 5HT re-uptake inhibitors can be found in the blood of babies being breast fed and in breast milk sertraline was undetectable in breast fed infants, even if it was present in a high concentration in the mother. Sertaline is therefore often considered one of the antidepressants of choice for nursing mothers who are depressed. It is always possible that the normal assessment methods for antidepressants might fail to detect tiny traces of the drug, and it is perhaps for this reason that the American Academy of Paediatrics recommends against the long term use of any of these antidepressants by nursing mothers. This advice wasn't based on any evidence of damage or adverse reaction to sertraline in babies, or even of its presence in babies who are breast fed.

Even before antidepressants were available I used to recommend that any patient who had been recently delivered and was suffering from depression should wean their baby early. Breast feeding if mother and child are enjoying it gives a baby a wonderful start, just as you have. Even so as any dairy farmer will tell you being regularly milked is very tiring, and nothing is worse for depression than becoming tired.

An excellent method for contraception for woman around 35 and more, who are in a stable relationship, is the Mirena coil. It is not without all risk of causing minor mood changes but from the experience of my practice I don't remember one patient who has had trouble from them, and in many cases the mood swings were much less once one was inserted.

Treating depression after a pregnancy is of the upmost importance, and as the reader implies keeping breast feeding going for twenty months has given the baby a head start.

I have been diagnosed as suffering from severe to moderate depression following a three month period of chronic stress brought on by work. I have been suffering from the stress and depression for the last six months. For the last five months I have been taking anti-depressants starting with 20mg of Citalopram rising to 40mg and for the last ten weeks Venlafaxine XL 225mg. Throughout this period I have been suffering from memory loss. In particular I find it difficult to recall what I did a few minutes ago and on a day to day, week to week and month to month basis. I recently read an article by you in which you stated that a person with damage to the Hippocampus lives only in the present. Is there any other explanation for my memory loss or am I correct in my self-diagnosis of a irreversible damaged Hippocampus which has brought on my current amnesia? Name and address withheld

No. I don't think that antidepressants cause permanent damage to the hippocampus. Patients who are depressed suffer from a poor memory partly because so many gloomy thoughts are making them preoccupied. As a result they fail to remember other events in their life. Their thoughts tend to go round and round in never ending and unproductive circles, so called psycho motor retardation. There is however no doubt that many antidepressants do have a reversible adverse effect on memory. I have noticed in my patients that it may also make them slightly slower at doing such intellectual tasks as mental arithmetic. People with permanent damage to their hippocampus, and associated areas, develop a generally poor memory and, as I know to my own cost, a specific inability to recognise and remember faces but not, I am glad to say, personal and clinical details of people.

Having suffered several bouts of depression since my late teens, I am now 28, I have been on and off Prozac for years and have worried increasingly about the long term effects the drug will have on my mind and my ability to function well in a natural state of mind. My latest depression started a couple of years ago during a relationship breakdown and I have been on 40mg of Prozac daily until about three months ago when, without the advice of my doctor, I ran out and decided not to get another prescription. I have been aware for years of the danger in such behaviour and have experienced the suicidal feelings and desperation that ensues which my GP had warned me of. I now have very mixed feelings, am experiencing mood swings and I fear that another bout of depression is inevitable. Please could you advise me of the dangers of cutting off the intake of Prozac so dramatically and if there is now any further evidence on the drug's long term effects and the mind's reliance on it? Leanne, Newcastle upon Tyne