antidepressant debate

January 13, 2010

There has been a debate for some time about the effectiveness of antidepressant medications, which are commonly used for anxiety and depression in routine psychiatric practice. A recent study published in the JAMA has reignited this debate, as it seems to indicate that there is little difference between antidepressants and placebo, for mild to moderate depression. In this large-scale randomised controlled trial patients with severe forms of depression benefited greatly from antidepressants when compared to placebo. Patients with mild to moderate depression seemed to respond both to antidepressants and to placebo.

This was discussed in depth at the Carlat Psychiatry Blog (written by a psychiatrist) It has been known for some time that the placebo response is powerful when it comes to depression and anxiety. This may indicate that these conditions naturally resolve with time, or perhaps it means that the power of belief has a very strong effect on mood – something we intuitively know to be true.

For psychiatrists, the question is whether or not we should prescribe antidepressants for the less serious forms of depression, and this is even more pertinent for GP’s who see the majority of such patients. It has been suggested that we should prescribe sugar pills for depression as the placebo response is so strong and this would benefit the patient without causing any side effects.

The majority of newer antidepressants have minimal side effects for the majority of patients. However there is a worrying trend towards increased suicidal thoughts in a small number of people, particularly adolescents. In practice antidepressant-induced suicide is virtually never seen, but this tends to show up in very large research trials.

I think this study also has implications for natural and alternative therapies, which are very popular but generally quite expensive for patients. We know that the placebo response is very strong, and so we can assume that the benefits of natural therapies are at least partly due to placebo response. Natural therapies are beneficial because they encourage healthy living and may assist mood in that way. It may be useful to bear in mind the placebo effect when considering the more costly therapies and may be advisable to seek a cheaper option!


Extra post for today, since I missed yesterday’s post. Putting sex in the title is sure to attract more visitors.

Today  someone sent me this article – new antidepressant increases sex drive – about a new antidepressant called flibanserin. The article refers to the drug as a “female Viagra” but really it’s nothing like Viagra at all (which affects blood circulation) but works on the brain in a similar way to other antidepressants.

The aphrodisiac properties of the medication were discovered by accident, at the end of a research trial. Basically, women tried on this drug were doing everything they could to hold onto it at the end of the trial, so someone started asking the questions.

It seems funny to me that many of our major medical breakthroughs were discovered by accident. Penicillin is the obvious one, but also lithium for Bipolar disorder – I just can’t think of any others, but feel free to leave a comment if you know one.

Anyone who is familiar with our common antidepressants will know that they often cause problems with libido. The patient is sometimes left with a choice of being depressed, or having no sex life – a really fun choice, at that. I imagine this drug will be one to watch when it is finally released, which may be several years in Australia at least.

Another interesting antidepressant to watch is agomelatine, a melatonin agonist. Melatonin is an important hormone in regulating our sleep-wake cycle and insomnia is a huge feature (cause and effect) of depression. So this one will be an interesting drug for the treatment of depression and insomnia. It’s already available in the UK but not Australia or the USA.


Mental health of Australians

November 18, 2009

Here’s my summary of the 2007 Australian National Survey of Mental Health and Wellbeing

This was a national face-to-face household survey of 8841 (60% response rate) community residents aged between 16 and 85. And the main points were:

• Nearly half of all Australians (45.5%) have experienced a mental disorder in their lifetimeOne in five Australians had experienced a mental disorder in the past 12 months

Anxiety disorders (14.4% in past 12 months) were the most common class of mental disorder. 6.2% had experienced mood disorders in past year (ie depression, bipolar disorder) 5.1% had experienced substance use disorders in past year

Disability: Mental disorders, particularly mood disorders, were disabling. On average, people with a mental disorder experienced nearly 4 days per month when they were unable to perform some or all of their usual activities. People with an anxiety disorder had 4 days out of role, people with a substance use disorder had 3 days out of role, while people with a mood disorder had 6 days out of role.

Comorbidity: One in four people (25.4%) with mental disorders in the past 12 month had more than one class of mental disorder. • One-third (34.9%) of people with a mental disorder (about 7% of population) used health services for mental health problems in the 12 months prior to the interview.

Females had a higher rates of depression & anxiety disorders • Males had higher rates of substance use disorders

Young adults: 25% (age 16-24) had experienced a mental disorder in the past 12 months, and young adults are the least likely group to access health services (22%)

• the prevalence of mental disorders declined with age

Service use: Females were more likely to use services than males. Those with mood disorders were most likely to make use of services (58.6%), followed by those with anxiety (37.8%) and substance use disorders (24.0%), respectively. 2.6% received treatment from a hospital, whereas 35% consulted a community-based provider – particularly general practitioners and psychologists. People aged 45-54 most likely to access services (42%)

• Comparison with 1997 Survey: It would appear that the 12 month prevalence of any anxiety disorder is higher in the 2007 NSMHWB (14.4%) compared to the 1997 NSMHWB (9.7%, 3). Although this may reflect a true change in prevalence over time, it may also be explained, at least in part, by differences in the two instruments used in the two surveys.

• The results of the survey place Australia as a country with one of the highest rates of mental disorder worldwide, in line with other developed countries such as the USA (26.2%, 25) and New Zealand (20.7%, 26).

• As was found in the Australian survey, anxiety disorders were the most common class of mental disorder in both the USA and New Zealand surveys. The prevalence of mood disorder was lower in the Australian survey compared to the USA and the New Zealand surveys. In contrast, the prevalence of substance use disorder was higher in the Australian survey compared to both the USA and New Zealand surveys.

Limitations: the survey interview does not attempt to detect low-prevalence and difficult-to-assess mental disorders, such as schizophrenia, personality disorders and dementia. Homeless people, people resident in nursing homes, hostels, and hospices and those in prison or other corrective service facilities were not surveyed • There was a lower than expected response rate (60%) which has implications for the validity of any estimates of the survey