New gene linked to depression

Everyone experiences some stress in their day-to-day lives but some people calm down after it more quickly than others. A chemical in the brain called neuropeptide Y (NPY) is thought to play a role in this and some variations in people's genes can cause them to produce lower levels of this chemical. Researchers from the University of Michigan Medical School studied 181 people. They analyzed their genes to see how effective they were at producing NPY and studied how they reacted to negative stimuli and whether they suffered from depression. The study found that people whose genes led them to produce low levels of NPY were more responsive to negative stimuli, less resilient to stress and more likely to develop major depression.

Body clocks, genes and depression

People suffering from depression can often suffer from sleep problems as well, particularly waking up early in the morning and not being able to get back to sleep again. Researchers from Ohio State University compared 30 people with a history of depression to 30 people who had never had it. They looked into levels of a substance called messenger RNA related to four genes which help govern people's body clocks. The participants who had had depression had a higher level of activity in the 'Clock' gene suggesting that they had a problem with their body clocks.

Dissection and depression

Scientists from Yale University have been dissecting dead people's brains in an attempt to find out more about depression. They analysed brain-tissue samples from 21 people who had been diagnosed with depression and compared them to 18 depression-free individuals. They found that a gene called MKP-1 was twice as active in the people who were depressed. The gene blocks a molecular pathway crucial to the survival and function of neurons.

You can find out more about this research here.

Genetic link for SAD

Past research has shown that seasonal affective disorder (SAD) tends to run in families. Researchers at the Uniformed Services University in Bethesda, Maryland, looked into the links between SAD and variations in genes responsible for the production of a hormone called melanopsin, which is produced in response to light and affects the body clock. The researchers found that people with SAD were more than five times as likely to have a particular variation of a gene called P10L responsible for the production of melanopsin.

You can find out more about this research at

http://www.mentalhelp.net/poc/view_doc.php?type=news&id=114464&cn=5

New gene linked to depression and anxiety

Attempts to establish a link between people's genes and their tendency to suffer from anxiety and depression have only been partially successful. A study of 3,107 people in Germany and the U.S. looked into the genetic origins of neuroticism. Neuroticism is a personality trait that reflects a tendency towards negative mood states and has been consistently associated with the likelihood of having symptoms of anxiety and depression. The study tested more than 420,000 genetic markers for their association with neuroticism. The most 'promising' gene for neuroticism, i.e. the one with the strongest link, was a gene called MAMDC1 on the 14th chromosome.

van den Oord, Edwin J.C.G. ... [et al] - Genomewide association analysis followed by a replication study implicates a novel candidate gene for neuroticism Archives of General Psychiatry September 2008, 65(9), 1062-1071

Drugs, genes and depression

Antidepressants are the most prescribed medicine in the U.S. with about 10% of adults taking prescription medication for depression. However, studies show that less than 50% of people treated for depression experience complete remission of their symptoms. Pharmacogenetics is the study of how people's genes interact with their medication and a U.S. study of 1,914 people looked into how people's genetic make-up affected the effectiveness of the antidepressant citalopram. The researchers found that White patients with a variation in the serotonin transporter gene SLC6A4 were more likely to see a remission of their symptoms after treatment with citalopram; but there was no difference for Black and Hispanic patients.

You can find out more about this research at

http://psychcentral.com/news/2008/07/16/genes-influence-antidepressant-effectiveness/2614.html

Inflammation and depression

There are clinical parallels between depressive symptoms and the symptoms of certain inflammatory disorders. Now researchers from the University of Miami have found genetic differences in inflammation-related genes that are associated with susceptibility to major depression. The researchers found the differences in a study of 615 Mexican-Americans in Los Angeles by comparing those with and without depression. The genes involved are also linked to psoriasis and asthma both of which are known to co-exist with depression and be brought on by psychosocial stressors.

You can find out more about this research at

http://psychcentral.com/news/2008/05/30/blood-test-may-identify-risk-for-depression/2380.html

Childhood abuse, genes and depression

Childhood abuse and early life stress are among the strongest contributors to adult depression. However, a U.S. study of 470 people has found that those people who suffered from adverse childhoods but who carry a gene called corticotropin-releasing hormone receptor one (CRHR1) had markedly lower measures of depression, compared with people with less protective forms of the gene. The study supports previous evidence that corticotropin-releasing hormone and related hormones play a role in depression.

You can find out more about this research at

http://psychcentral.com/news/2008/02/06/gene-protects-from-depression-after-childhood-abuse/1880.html

Genes, depression and Russian mothers

Recent research into the causes of mental illness suggests that genetics and environment, rather than one or the other, interact to cause psychological problems. In depression an individual's genetic make-up can predispose some people to be more susceptible to the condition when they are confronted with negative life experiences. A study of 177 male adolescents in a juvenile detention centre in Russia looked at the presence of a gene involved in the transport of the neurotransmitter dopamine (which is believed to have an important role in depression), levels of depression and the influence of rejecting child-rearing by mothers such as physical punishment, hostility, lack of respect for the child's point of view and unjustified criticism in front of others. While neither the gene or rejecting mothers on their own predicted depression the presence of both together led to a higher risk for major depression and suicidal ideation.

You can find out more about this research at

http://psychcentral.com/news/2008/01/15/genetic-and-environmental-stimulus-for-depression/1781.html

Genes, gender and depression

Two studies of the interactions between genes, gender, stress and depression have shown that the relationships between these different factors are more complex than many newspaper reports would suggest. Researchers looked at two groups of people one who had had deprived childhoods (suffered stress early in life) and the other who were caregivers (suffered stress later in life). They examined levels of stress and depression and related them to a variation in a gene that regulates levels of serotonin, a brain chemical known to be linked to depression. The researchers found that women with the 'short' version of the gene were more likely to suffer from depression when they were stressed whereas for men it was the 'long' version of the gene which placed them more at risk. The effect of the stress was consistent regardless of whether it occured early or late in life. The researchers suggested that those people with the gene variation ('short' in women 'long' in men) that increased the risk of stress-related depression and who are in stressful situations could benefit from preventive measures such as positive social support or training in stress-coping skills to prevent them from becoming depressed.

You can find out more about this study at

http://psychcentral.com/news/2007/11/30/genetics-place-women-at-risk-for-depression/1595.html