Looking back over relevant research papers that caught my attention last month, some stand out for me more than the others.  Here are three on depression that stood out and got me thinking.  The Fergusson et al paper looks at links between alcohol abuse and major depression.  There has been debate for years on whether alcohol dependence leads to depression or depression leads to alcohol dependence.  In this kind of debate, it's usually a good bet that both pathways contain some truth.  What this study adds is that often it is the alcohol dependence that is primary.  As the authors state " ... the associations between AAD (alcohol abuse or dependence) and MD (major depression) were best explained by a causal model in which problems with alcohol led to increased risk of MD as opposed to a self-medication model in which MD led to increased risk of AAD." 

Last month's article in the British Medical Journal on the dangers posed by radon gas in buildings jogged my awareness of this important hazard (Gray, Read et al. 2009).  Quoting Wikipedia on radon "Radon is the invisible, radioactive mono-atomic gas that results from radioactive decay of some forms of uranium that may be found in rock formations beneath buildings or in certain building materials themselves. There are relatively simple tests for radon gas, but these tests are not commonly done, even in areas of known systematic hazards." and "According to the United States Environmental Protection Agency, radon is reportedly the second most frequent cause of lung cancer, after cigarette smoking; and radon-induced lung cancer the 6th leading cause of cancer death overall." and "Some ... areas, including Cornwall and Aberdeenshire in the United Kingdom have high enough natural radiation levels that nuclear licensed sites cannot be built there - the sites would already exceed legal radiation limits before they opened, and the natural topsoil and rock would all have to be disposed of as low-level nuclear waste."

Here are a couple of studies on the prevalence of depression and anxiety, and four on risk factors for depression, bipolar disorder and suicide.  Strine et al report on a major survey of depression and anxiety in the United States.  They found "The overall prevalence of current depressive symptoms was 8.7% (range by state and territory, 5.3%-13.7%); of a lifetime diagnosis of depression, 15.7% (range, 6.8%-21.3%); and of a lifetime diagnosis of anxiety, 11.3% (range, 5.4%-17.2%)."  Smoking, lack of exercise, and excessive drinking were all associated with increased likelihood of mental disorders, as too was physical ill health.  Young et al, in a separate study, looked at the likelihood of depression and anxiety becoming persistent.  They estimated - at nearly 3 year follow-up - that the US prevalence of persistent depressive or anxiety disorder was 4.7%.  Only about a quarter of these sufferers were using appropriate medication and only about a fifth appropriate counselling.

Here are two papers on mindfulness and four on sleep.  The Kuyken et al paper is important.  It compares mindfulness-based cognitive therapy (MBCT) with continuation antidepressants in the prevention of relapse in recurrent depression.  The results are great - "Relapse/recurrence rates over 15-month follow-ups in MBCT were 47%, compared with 60% in the m-ADM (maintenance antidepressant) group (hazard ratio = 0.63; 95% confidence interval: 0.39 to 1.04).  MBCT was more effective than m-ADM in reducing residual depressive symptoms and psychiatric comorbidity and in improving quality of life in the physical and psychological domains."  I have been cautious in my enthusiasm for MBCT (see previous post) but this is exactly the kind of research that we need to help clarify MBCT's potential further.  The second paper on mindfulness is lower key.  It is a mention of its potential in enhancing sexuality.  It makes sense - see last month's posts on the effects of meditation training on experiencing positive emotions - but the relevant research is still in its early stages.