Ketamine relieves depression within hours

Ketamine may provide insight into new mechanisms for medication development for depression:

A drug used as a general anaesthetic may also work as a remarkably rapid antidepressant, according to a preliminary study.

The drug’s hallucinogenic side effects mean it is unlikely to be prescribed to patients, but it could pave the way to new faster-acting antidepressants, the researchers suggest.

Ketamine is used as an animal tranquiliser, but is perhaps better known as an illicit street drug, sometimes called “special K”. Now researchers have found the drug can relieve depression in some patients within just 2 hours – and continue to do so for a week.

Bias in co-occurring research

An interesting new study on drinking and depression:

"Not all studies have found a significant relationship between drinking and depression," said Kathryn Graham, senior scientist at the Centre for Addiction and Mental Health, "and some have found a relationship for one gender but not the other. In our study, we included two quite different types of measures of depression. We also used four clearly different types of alcohol consumption measures that examined both drinking pattern as well as overall consumption." Graham is the corresponding author for the study.

I hate to sound jaded, but when I read this it felt a little like a search for conclusive proof of a strong relationship between the two and self-medication as the probable explanation. I figured I was just too jaded and read on...

Results indicate that measurement and gender are key issues in interpreting findings on the relationship between alcohol and depression. Specifically, depression is primarily related to drinking larger quantities per occasion, is unrelated to drinking frequency, and these effect are stronger for women than for men.

"Depression is most strongly related to a pattern of binge drinking," said Graham. "A pattern of frequent but low quantity drinking is not associated with depression. In fact, those who usually drink less than two drinks per occasion and never drink as much as five drinks are less depressed -- for both measures of depression -- than former drinkers. This relationship with drinking pattern is greater for women than for men."

Second, the overall relationship between depression and alcohol consumption is stronger for women than for men, but only when depression is measured as meeting a clinical diagnosis of major depression. Conversely, there is no gender difference when depression is measured as recent depressed feelings, which is commonly done in research on this topic.

The first conclusion is interesting--it makes a lot of sense that depression would be more strongly associated with heavy drinking episodes rather than the frequency of drinking. The second finding also is not surprising, women self-report depressive symptoms at higher levels then men, and the study is based on a phone survey.

Finally comes the self-medication hypothesis:

"This pattern of associations is more consistent with women using alcohol to counteract depression -- by high-quantity drinking and intoxication -- than with chronic alcohol consumption tending to make women depressed," said Wilsnack. "However, a vicious circle could possibly begin with drinking in response to depression....

The bottom line, said Wilsnack, is that "clinical depression may encourage some women to drink large amounts of alcohol in hopes of numbing depressed feelings, with risks of alcohol abuse and dependence. Therefore, clinicians treating women for depression really need to be concerned about women's use of alcohol, because of the risks that women may try to medicate their moods with alcohol."

This in spite of the fact that the source article itself says "these cross-sectional data do not provide information about temporal ordering or causation".

Experience Sculpts Brain Circuitry to Build Resiliency to Stress

A sense of mastery (real or perceived) not only affects the response to that stressor, but also future stressors.

It's long been known that experiencing control over a stressor immunizes a rat from developing a depression-like syndrome when it later encounters stressors that it can't control. Now, scientists funded by the National Institute of Mental Health (NIMH), part of the National Institutes of Health (NIH), have unraveled the workings of the brain circuitry that inoculates against such hard knocks – the circuitry of resilience.

Control not only activated the brain's executive hub, the prefrontal cortex, but also altered it so that it later activated even when the stressor was not controllable. This activation turned off mood-regulating cells in the brainstem's alarm center. The immunizing effect was so powerful that even a week later, when confronted with an uncontrollable stressor, the cells behaved as if the stressor was controllable and the rat was protected.

"It's as if the original experience with control leads the animal to later have the illusion of control even when it's absent, thereby producing resilience in the face of challenge," explained NIMH grantee Steven Maier, Ph.D., University of Colorado. "The prefrontal cortex is necessary for processing information about the controllability of stressors as well as applying this information to regulate responses to subsequent stressors."

I wonder if this helps explain two phenomena that we all witness in treatment and recovery:

• The description of "lack of control over a stressful situation" describes the life of an addict experiencing loss of control. We are all aware of the understandable symptoms of depression and the demoralization in which many people enter recovery. Maybe this explains one of the mechanisms for this depression and one of the mechanisms of the emotional rehabilitation that happens in recovery. We've all heard sponsors and counselors tell newcomers to "do the next right thing" in spite of their fear.
• Second, I wonder if this helps explain those that appear to be relatively immune to stress. We've all seen addicts who face death and disaster and walk away relatively stress-free. They fail to experience that motivational crisis, "moment of clarity" or deflation necessary to take stock and decide to pursue a radical change in course. Could perceived mastery over early stressful experiences create excessive resiliency?

[via TxDirector.com]