Clinical depression is a medical condition caused by biochemical disorders that interfere with normal functioning and can, in some cases, lead to death from suicide. It is distinct from 'depression as short-lived, unhappy feelings that may be linked to a particular event.

A related condition to clinical depression is known as dysthymia, or chronic sadness.

Causes

Depression is frequently the result of or the reaction to illness or social problems, but on occasions no specific cause or factors can be identified.

If depression is less severe it is described as dysthymia. Symptoms are defined as poor appetite, poor sleep, fatigue, low self-esteem and feelings of hopelessness much of the time for at least two years. Dysthymia is often the prelude to more severe depressive episodes, and in itself has a considerable effect on quality of life.

Some of these symptoms may be induced by HIV disease itself or by HIV medications, and these causes should be eliminated before a psychiatric diagnosis is made.

In women with HIV, depression has been associated with disease progression and death (Ickovics 2001). Studies have found that men with HIV or AIDS are more likely to develop depression than the general population, particularly in those aged over 50 (Justice 2004). Co-infection with hepatitis C virus increases the risk of the development of depression (Yang 2004). However, men with AIDS who have a pet are less likely to experience depression than those men who do not have a pet.

Poor nutrition, lack of sunlight and lack of exercise may all contribute to depression. Conversely, depression has been associated with an increased incidence of unsafe sex and poor adherence to antiretroviral drug regimens (Desquilbet 2003; Chin-Hong 2004; Kleeberger 2004; Vincent 2004)

Diagnosis

Depression is defined as the presence of most or all of the following symptoms on a daily basis for several weeks: depressed mood; apathy; irritability; significant, unintentional weight loss or weight gain; insomnia, early waking or oversleeping; fatigue; loss of interest or pleasure in usual activities; feelings of low self-worth or excessive guilt; poor concentration; recurrent thoughts of death or suicide.

Treating depression

If practical difficulties are the reason for less severe depression then dealing with these or obtaining advice on how to resolve them may be of help. For more severe depression, then help is available from trained counsellors, psychologists and psychiatrists. This can be accessed through an HIV clinic or voluntary HIV / AIDS services.

Doctors or psychiatrists may suggest the use of anti-depressants, drugs that relieve the symptoms of depression by acting on the brains neurotransmitter chemicals. Anti-depressant drugs may be of help especially if depression is accompanied by physical symptoms such as weight loss or sleep problems. They usually take a few weeks to work and have side-effects which should be discussed with a doctor. Often psychotherapy and drug treatments are combined, and some research suggests this is more effective treatment.

There are three main types of anti-depressant drugs:

• Tricyclic anti-depressants (TCAs) were developed in the 1950s, including amitriptyline, nortriptyline (Allegron) and desipramine. Side-effects include confusion, drowsiness, dry mouth, weight gain, blurred vision and sexual problems.

• Monoamine oxidase inhibitors (MAOIs) include phenelzine (Nardil), isocarboxazid and tranylcypromine. These drugs can cause side-effects, including tremors, insomnia, weight gain and liver toxicity, and may interact with some foods to cause a sudden, life-threatening increase in blood pressure. As a consequence, these drugs are rarely prescribed.

• Selective serotonin re-uptake inhibitors (SSRIs) are the most recent type of anti-depressant to be developed. The group includes fluoxetine (Prozac), citalopram (Cipramil), escitalopram (Cipralex), fluvoxamine (Faverin), paroxetine (Seroxat) and sertraline (Lustral). Due to their better side-effect profile, these drugs are more frequently prescribed than the other drug classes. Nevertheless, a significant proportion of people experience early side-effects such as diarrhoea, insomnia, giddiness and nausea. These usually resolve after one to two months of treatment. Fluoxetine tends to be prescribed more frequently than other SSRIs because of a larger body of experience in its use and fewer concerns about potential for withdrawal symptoms. SSRIs also have fewer interactions with other drugs and do not usually cause weight gain, although they can affect sexual function. Impotence or delayed ejaculation are side-effects which may affect 10-20% of people taking fluoxetine, for example.

It is unclear how long anti-depressants should be taken for in order to 'cure' depression. There are many conflicting theories amongst psychiatrists and psychotherapists about the treatment of depression. Some argue that anti-depressants only need to be taken for a short period of time (three to six months), but others suggest that they may need to be taken for longer.

The herbal remedy St John's wort (Hypericum perforatum), which contains 0.3% hypericum and 6% hyperforin, is a commonly used treatment with proven effectiveness against mild depression, but not against moderately serious depression. St John's wort should not be taken at the same time as protease inhibitors or non-nucleoside reverse transcriptase inhibitors (NNRTIs), since it can reduce blood levels of these drugs.

Depression and testosterone

Depression in HIV-positive people has also been linked to low levels of testosterone, a hormone which can affect mood, energy, weight and sexual arousal. A number of small studies have found evidence of low testosterone levels in HIV-positive men (hypogonadism), but no properly controlled studies have yet been conducted to review the effects of testosterone and dehydroepiandrosterone (DHEA; an intermediate form of testosterone) on mood, energy levels and other symptoms of depression. However, there are frequent anecdotal reports that both substances have an impact on depressive symptoms, and a study is currently taking place in the United States comparing the effects of testosterone with fluoxetine.

See also Anxiety and Memory problems in Symptoms and illnesses: A to Z of symptoms.

References

Chin-Hong PV et al. High-risk sexual behavior in HIV-infected adults with genotypically proven antiretroviral resistance. Eleventh Conference on Retroviruses and Opportunistic Infections, San Francisco, abstract 845, 2004.

Desquilbet L et al. Increase in at-risk sexual behaviour among HIV-1-infected patients followed in the French PRIMO cohort. AIDS 16: 2329-2333, 2003.

Ickovics JR et al. Mortality, CD4 cell count decline, and depressive symptoms among HIV-seropositive women: longitudinal analysis from the HIV epidemiology research study. Journal of the American Medical Association 285(11): 1466-1474, 2001.

Justice AC et al. Psychiatric and neurocognitive disorders among HIV-positive and negative veterans in care: Veterans Aging Cohort Five-Site Study. AIDS 18: S49-S59, 2004.

Kleeberger CA et al. Changes in adherence to highly active antiretroviral therapy medications in the Multicenter AIDS Cohort Study. AIDS 18: 683-688, 2004.

Markowitz JC et al. Treating depression in HIV-positive patients. AIDS 8(4): 403-412, 1994.

Markowitz JC et al. Treatment of depressive symptoms in human immunodeficiency virus-positive patients. Archives of General Psychiatry 55:452-457, 1998.

Siegel JM et al. AIDS diagnosis and depression in the Multicenter AIDS Cohort Study: the ameliorating impact of pet ownership. AIDS Care 11(2 ): 157-170 , 1999.

Vincent E et al. Impact of HAART-related side-effects on unsafe sexual behaviours in HIV-infected injecting drug users: 7-year follow-up. AIDS 18: 1321-1325, 2004.

Yang Y et al. Hepatitis C and neuropsychological function in treatment-naive HIV-1-infected subjects - A5097s baseline analysis. Eleventh Conference on Retroviruses and Opportunistic Infections, San Francisco, abstract 26, 2004.