News Topic depression
About these topic collections
I’ve been reporting on memory research for over ten years and these topic pages are simply collections of all the news items I have made on a particular topic. They do not pretend to be in any way exhaustive! I cover far too many areas within memory to come anywhere approaching that. What I aim to do is provide breadth, rather than depth. Outside my own area of cognitive psychology, it is difficult to know how much weight to give to any study (I urge you to read my blog post on what constitutes scientific evidence). That (among other reasons) is why my approach in my news reporting is based predominantly on replication and consistency. It's about the aggregate. So here is the aggregate of those reports I have at one point considered of sufficient interest to discuss. If you know of any research you would like to add to the collection, feel free to write about it in a comment (please provide a reference).
There's quite a bit of evidence now that socializing — having frequent contact with others — helps protect against cognitive impairment in old age. We also know that depression is a risk factor for cognitive impairment and dementia. There have been hints that loneliness might also be a risk factor. But here’s the question: is it being alone, or feeling lonely, that is the danger?
A large Dutch study, following 2173 older adults for three years, suggests that it is the feeling of loneliness that is the main problem.
At the start of the study, some 46% of the participants were living alone, and some 50% were no longer or never married (presumably the discrepancy is because many older adults have a spouse in a care facility). Some 73% said they had no social support, while 20% reported feelings of loneliness.
Those who lived alone were significantly more likely to develop dementia over the three year study period (9.3% compared with 5.6% of those who lived with others). The unmarried were also significantly more likely to develop dementia (9.2% vs 5.3%).
On the other hand, among those without social support, 5.6% developed dementia compared with 11.4% with social support! This seems to contradict everything we know, not to mention the other results of the study, but the answer presumably lies in what is meant by ‘social support’. Social support was assessed by the question: Do you get help from family, neighbours or home support? It doesn’t ask the question of whether help would be there if they needed it. So this is not a question of social networks, but more one of how much you need help. This interpretation is supported by the finding that those receiving social support had more health problems.
So, although the researchers originally counted this question as part of the measure of social isolation, it is clearly a poor reflection of it. Effectively, then, that leaves cohabitation and marriage as the only indices of social isolation, which is obviously inadequate.
However, we still have the interesting question re loneliness. The study found that 13.4% of those who said they felt lonely developed dementia compared with 5.7% of those who didn’t feel this way. This is a greater difference than that found with the ‘socially isolated’ (as measured!). Moreover, once other risk factors, such as age, education, and other health factors, were accounted for, the association between living alone and dementia disappeared, while the association with feelings of loneliness remained.
Of course, this still doesn’t tell us what the association is! It may be that feelings of loneliness simply reflect cognitive changes that precede Alzheimer’s, but it may be that the feelings themselves are decreasing cognitive and social activity. It may also be that those who are prone to such feelings have personality traits that are in themselves risk factors for cognitive impairment.
I would like to see another large study using better metrics of social isolation, but, still, the study is interesting for its distinction between being alone and feeling lonely, and its suggestion that it is the subjective feeling that is more important.
This is not to say there is no value in having people around! For a start, as discussed, the measures of social isolation are clearly inadequate. Moreover, other people play an important role in helping with health issues, which in turn greatly impact cognitive decline.
Although there was a small effect of depression, the relationship between feeling lonely and dementia remained after this was accounted for, indicating that this is a separate factor (on the other hand feelings of loneliness were a risk factor for depression).
A decrease in cognitive score (MMSE) was also significantly greater for those experiencing feelings of loneliness, suggesting that this is also a factor in age-related cognitive decline.
The point is not so much that loneliness is more detrimental than being alone, but that loneliness in itself is a risk factor for cognitive decline and dementia. This suggests that we should develop a better understanding of loneliness, how to identify the vulnerable, and how to help them.
 Feelings of loneliness, but not social isolation, predict dementia onset: results from the Amsterdam Study of the Elderly (AMSTEL). Journal of Neurology, Neurosurgery & Psychiatry.(2012).
Full text available at http://press.psprings.co.uk/jnnp/december/jnnp302755.pdf
Problems with myelin — demyelination (seen most dramatically in MS, but also in other forms of neurodegeneration, including normal aging and depression); failure to develop sufficient myelin (in children and adolescents) — are increasingly being implicated in a wide range of disorders. A new animal study adds to that evidence by showing that social isolation brings about both depression and loss of myelin.
In the study, adult mice were isolated for eight weeks (which is of course longer for a mouse than it is to us) to induce a depressive-like state. They were then introduced to a mouse they hadn’t seen before. Although typically very social animals, those who had been socially isolated didn’t show any interest in interacting with the new mouse — a common pattern in human behavior as well.
Analysis of their brains revealed significantly lower levels of gene transcription for oligodendrocyte cells (the components of myelin) in the prefrontal cortex. This appeared to be caused by a lower production of heterochromatin (tightly packed DNA) in the cell nuclei, producing less mature oligodendrocytes.
Interestingly, even short periods of isolation were sufficient to produce changes in chromatin and myelin, although behavior wasn’t affected.
Happily, however, regardless of length of isolation, myelin production went back to normal after a period of social integration.
The findings add to the evidence that environmental factors can have significant effects on brain development and function, and support the idea that socializing is good for the brain.
 Impaired adult myelination in the prefrontal cortex of socially isolated mice. Nature Neuroscience. 15(12), 1621 - 1623.(2012).
Sometime ago, I reported on a study showing that older adults could improve their memory for a future task (remembering to regularly test their blood sugar) by picturing themselves going through the process. Imagination has been shown to be a useful strategy in improving memory (and also motor skills). A new study extends and confirms previous findings, by testing free recall and comparing self-imagination to more traditional strategies.
The study involved 15 patients with acquired brain injury who had impaired memory and 15 healthy controls. Participants memorized five lists of 24 adjectives that described personality traits, using a different strategy for each list. The five strategies were:
For both groups, self-imagination produced the highest rates of free recall of the list (an average of 9.3 for the memory-impaired, compared to 3.2 using the baseline strategy; 8.1 vs 3.2 for the controls — note that the controls were given all 24 items in one list, while the memory-impaired were given 4 lists of 6 items).
Additionally, those with impaired memory did better using semantic self-referential processing than episodic self-referential processing (7.3 vs 5.7). In contrast, the controls did much the same in both conditions. This adds to the evidence that patients with brain injury often have a particular problem with episodic memory (knowledge about specific events). Episodic memory is also particularly affected in Alzheimer’s, as well as in normal aging and depression.
It’s also worth noting that all the strategies that involved the self were more effective than the two strategies that didn’t, for both groups (also, semantic elaboration was better than the baseline strategy).
The researchers suggest self-imagination (and semantic self-referential processing) might be of particular benefit for memory-impaired patients, by encouraging them to use information they can more easily access (information about their own personality traits, identity roles, and lifetime periods — what is termed the self-schema), and that future research should explore ways in which self-imagination could be used to support everyday memory tasks, such as learning new skills and remembering recent events.
 Imagining a Better Memory Self-Imagination in Memory-Impaired Patients. Clinical Psychological Science.(2012).
Full text available at http://cpx.sagepub.com/content/early/2012/10/02/2167702612456464
We know that people with depression tend to focus on, and remember, negative memories rather than positive. Interestingly, it’s not simply an emotion effect. People with depression, and even those at risk of depression (including those who have had depression), tend to have trouble remembering specific autobiographical memories. That is, memories of events that happened to them at a specific place and time (as opposed to those generalized event memories we construct from similar events, such as the ‘going to the dentist’ memory).
This cognitive difficulty seems to exacerbate their depression, probably through its effect on social encounters and relationships.
A new study, however, has found that a particular training program (“Memory Specificity Training”) can help both their memory for specific events and their symptoms of depression.
The study involved 23 adolescent Afghani refugees in Iran, all of whom had lost their fathers in the war in Afghanistan and who showed symptoms of depression. Half were randomly assigned to the five-week memory training program and half received no training.
The training program involved a weekly 80-minute group session, in which participants learned about different types of memory and memory recall, and practiced recalling specific memories after being given positive, neutral, and negative keywords.
Participants’ memory for specific events was tested at the start of the study, at the end of the five-week training period, and two months after the end of the training. Compared to the control group, those given the training were able to provide more specific memories after the training, and showed fewer symptoms of depression at the two month follow-up (but not immediately after the end of training).
The study follows on from a pilot study in which ten depressed female patients were given four weekly one-hour sessions of memory training. Improvements in memory retrieval were associated with less rumination (dwelling on things), less cognitive avoidance, and improvements in problem-solving skills.
It’s somewhat unfortunate that the control group were given no group sessions, indeed no contact (apart from the tests) of any kind. Nevertheless, and bearing in mind that these are still very small studies, the findings do suggest that it would be helpful to include a component on memory training in any cognitive behavioral therapy for depression.
 Enhancing Autobiographical Memory Specificity Through Cognitive Training An Intervention for Depression Translated From Basic Science. Clinical Psychological Science.(2012).
Full text available at http://cpx.sagepub.com/content/early/2012/09/07/2167702612454613.abstract
I have reported previously on research suggesting that rapamycin, a bacterial product first isolated from soil on Easter Island and used to help transplant patients prevent organ rejection, might improve learning and memory. Following on from this research, a new mouse study has extended these findings by adding rapamycin to the diet of healthy mice throughout their life span. Excitingly, it found that cognition was improved in young mice, and abolished normal cognitive decline in older mice.
Anxiety and depressive-like behavior was also reduced, and the mice’s behavior demonstrated that rapamycin was acting like an antidepressant. This effect was found across all ages.
Three "feel-good" neurotransmitters — serotonin, dopamine and norepinephrine — all showed significantly higher levels in the midbrain (but not in the hippocampus). As these neurotransmitters are involved in learning and memory as well as mood, it is suggested that this might be a factor in the improved cognition.
Other recent studies have suggested that rapamycin inhibits a pathway in the brain that interferes with memory formation and facilitates aging.
 Inhibition of mTOR by Rapamycin Abolishes Cognitive Deficits and Reduces Amyloid-β Levels in a Mouse Model of Alzheimer's Disease. PLoS ONE. 5(4), e9979 - e9979.(2010).
 Selective pharmacogenetic inhibition of mammalian target of Rapamycin complex I (mTORC1) blocks long-term synaptic plasticity and memory storage. Proceedings of the National Academy of Sciences. 108(9), 3791 - 3796.(2011).
The study involved 104 healthy older adults (average age 87) participating in the Oregon Brain Aging Study. Analysis of the nutrient biomarkers in their blood revealed that those with diets high in omega 3 fatty acids and in vitamins C, D, E and the B vitamins had higher scores on cognitive tests than people with diets low in those nutrients, while those with diets high in trans fats were more likely to score more poorly on cognitive tests.
These were dose-dependent, with each standard deviation increase in the vitamin BCDE score ssociated with a 0.28 SD increase in global cognitive score, and each SD increase in the trans fat score associated with a 0.30 SD decrease in global cognitive score.
Trans fats are primarily found in packaged, fast, fried and frozen food, baked goods and margarine spreads.
Brain scans of 42 of the participants found that those with diets high in vitamins BCDE and omega 3 fatty acids were also less likely to have the brain shrinkage associated with Alzheimer's, while those with high trans fats were more likely to show such brain atrophy.
Overall, the participants had good nutritional status, but 7% were deficient in vitamin B12 (I’m surprised it’s so low, but bear in mind that these are already a select group, being healthy at such an advanced age) and 25% were deficient in vitamin D.
The nutrient biomarkers accounted for 17% of the variation in cognitive performance, while age, education, APOE genotype (presence or absence of the ‘Alzheimer’s gene’), depression and high blood pressure together accounted for 46%. Diet was more important for brain atrophy: here, the nutrient biomarkers accounted for 37% of the variation, while the other factors accounted for 40% (meaning that diet was nearly as important as all these other factors combined!).
The findings add to the growing evidence that diet has a significant role in determining whether or not, and when, you develop Alzheimer’s disease.
 Nutrient biomarker patterns, cognitive function, and MRI measures of brain aging. Neurology. 78(4), 241 - 249.(2012).
In the last five years, three studies have linked lower neighborhood socioeconomic status to lower cognitive function in older adults. Neighborhood has also been linked to self-rated health, cardiovascular disease, and mortality. Such links between health and neighborhood may come about through exposure to pollutants or other environmental stressors, access to alcohol and cigarettes, barriers to physical activity, reduced social support, and reduced access to good health and social services.
Data from the large Women’s Health Initiative Memory Study has now been analyzed to assess whether the relationship between neighborhood socioeconomic status can be explained by various risk and protective factors for poor cognitive function.
Results confirmed that higher neighborhood socioeconomic status was associated with higher cognitive function, even after individual factors such as age, ethnicity, income, education, and marital status have been taken into account. A good deal of this was explained by vascular factors (coronary heart disease, diabetes, stroke, hypertension), health behaviors (amount of alcohol consumed, smoking, physical activity), and psychosocial factors (depression, social support). Nevertheless, the association was still (barely) significant after these factors were taken account of, suggesting some other factors may also be involved. Potential factors include cognitive activity, diet, and access to health services.
In contradiction of earlier research, the association appeared to be stronger among younger women. Consistent with other research, the association was stronger for non-White women.
Data from 7,479 older women (65-81) was included in the analysis. Cognitive function was assessed by the Modified MMSE (3MSE). Neighborhood socioeconomic status was assessed on the basis of: percentage of adults over 25 with less than a high school education, percentage of male unemployment, percentage of households below the poverty line, percentage of households receiving public assistance, percentage of female-headed households with children, and median household income. Around 87% of participants were White, 7% Black, 3% Hispanic, and 3% other. Some 92% had graduated high school, and around 70% had at least some college.
 Neighborhood Socioeconomic Status and Cognitive Function in Women. Am J Public Health. 101(9), 1721 - 1728.(2011).
Lang IA, Llewellyn DJ, Langa KM, Wallace RB, Huppert FA, Melzer D. 2008. Neighborhood deprivation, individual socioeconomic status, and cognitive function in older people: analyses from the English Longitudinal Study of Ageing. J Am Geriatr Soc., 56(2), 191-198.
Sheffield KM, Peek MK. 2009. Neighborhood context and cognitive decline in older Mexican Americans: results from the Hispanic Established Populations for Epidemiologic Studies of the Elderly. Am J Epidemiol., 169(9), 1092-1101.
Wight RG, Aneshensel CS, Miller-Martinez D, et al. 2006. Urban neighborhood context, educational attainment, and cognitive function among older adults. Am J Epidemiol., 163(12), 1071-1078.
A ten-year study involving 7,239 older adults (65+) has found that each common health complaint increased dementia risk by an average of about 3%, and that these individual risks compounded. Thus, while a healthy older adult had about an 18% chance of developing dementia after 10 years, those with a dozen of these health complaints had, on average, closer to a 40% chance.
It’s important to note that these complaints were not for serious disorders that have been implicated in Alzheimer’s. The researchers constructed a ‘frailty’ index, involving 19 different health and wellbeing factors: overall health, eyesight, hearing, denture fit, arthritis/rheumatism, eye trouble, ear trouble, stomach trouble, kidney trouble, bladder control, bowel control, feet/ankle trouble, stuffy nose/sneezing, bone fractures, chest problems, cough, skin problems, dental problems, other problems.
Not all complaints are created equal. The most common complaint — arthritis/rheumatism —was only slightly higher among those with dementia. Two of the largest differences were poor eyesight (3% of the non-demented group vs 9% of those with dementia) and poor hearing (3% and 6%).
At the end of the study, 4,324 (60%) were still alive, and of these, 416 (9.6%) had Alzheimer's disease, 191 (4.4%) had another sort of dementia and 677 (15.7%) had other cognitive problems (but note that 1,023 were of uncertain cognitive ability).
While these results need to be confirmed in other research — the study used data from broader health surveys that weren’t specifically designed for this purpose, and many of those who died during the study will have probably had dementia — they do suggest the importance of maintaining good general health.
Common irregular heartbeat raises risk of dementia
In another study, which ran from 1994 to 2008 and followed 3,045 older adults (mean age 74 at study start), those with atrial fibrillation were found to have a significantly greater risk of developing Alzheimer’s.
At the beginning of the study, 4.3% of the participants had atrial fibrillation (the most common kind of chronically irregular heartbeat); a further 12.2% developed it during the study. Participants were followed for an average of seven years. Over this time, those with atrial fibrillation had a 40-50% higher risk of developing dementia of any type, including probable Alzheimer's disease. Overall, 18.8% of the participants developed some type of dementia during the course of the study.
While atrial fibrillation is associated with other cardiovascular risk factors and disease, this study shows that atrial fibrillation increases dementia risk more than just through this association. Possible mechanisms for this increased risk include:
The next step is to see whether any treatments for atrial fibrillation reduce the risk of developing dementia.
Stress may increase risk for Alzheimer's disease
And a rat study has shown that increased release of stress hormones leads to cognitive impairment and that characteristic of Alzheimer’s disease, tau tangles. The rats were subjected to stress for an hour every day for a month, by such means as overcrowding or being placed on a vibrating platform. These rats developed increased hyperphosphorylation of tau protein in the hippocampus and prefrontal cortex, and these changes were associated with memory deficits and impaired behavioral flexibility.
Previous research has shown that stress leads to that other characteristic of Alzheimer’s disease: the formation of beta-amyloid.
 Nontraditional risk factors combine to predict Alzheimer disease and dementia. Neurology. 77(3), 227 - 234.(2011).
 Atrial Fibrillation and Risk of Dementia: A Prospective Cohort Study. Journal of the American Geriatrics Society. 59(8), 1369 - 1375.(2011).
 Stress Acts Cumulatively To Precipitate Alzheimer's Disease-Like Tau Pathology and Cognitive Deficits. The Journal of Neuroscience. 31(21), 7840 - 7847.(2011).
Following several recent studies pointing to the negative effect of air pollution on children’s cognitive performance (see this April 2010 news report and this May 2011 report), a study of public schools in Michigan has found that 62.5% of the 3660 schools in the state are located in areas with high levels of industrial pollution, and those in areas with the highest industrial air pollution levels had the lowest attendance rates and the highest proportions of students who failed to meet state educational testing standards in English and math. Attendance rates are a potential indicator of health levels.
Minority students were especially hit by this — 81.5% of African American and 62.1% of Hispanic students attend schools in the top 10% of the most polluted areas, compared to 44.4% of white students.
Almost all (95%) of the industrial air pollution around schools comes from 12 chemicals (diisocyanates, manganese, sulfuric acid, nickel, chlorine, chromium, trimethylbenzene, hydrochloric acid, molybdenum trioxide, lead, cobalt and glycol ethers) that are all implicated in negative health effects, including increased risk of respiratory, cardiovascular, developmental and neurological disorders, as well as cancer.
There are potentially two issues here: the first is that air pollution causes health issues which lower school attendance and thus impacts academic performance; the other is that the pollution also directly effects the brain, thus affecting cognitive performance.
A new mouse study looking at the effects of air pollution on learning and memory has now found that male mice exposed to polluted air for six hours a day, five days a week for 10 months (nearly half their lifespan), performed significantly more poorly on learning and memory tasks than those male mice living in filtered air. They also showed more signs of anxiety- and depressive-like behaviors.
These changes in behavior and cognition were linked to clear differences in the hippocampus — those exposed to polluted air had fewer dendritic spines in parts of the hippocampus (CA1 and CA3 regions), shorter dendrites and overall reduced cell complexity. Previous mouse research has also found that such pollution causes widespread inflammation in the body, and can be linked to high blood pressure, diabetes and obesity. In the present study, the same low-grade inflammation was found in the hippocampus. The hippocampus is particularly sensitive to damage caused by inflammation.
The level of pollution the mice were exposed to was equivalent to what people may be exposed to in some polluted urban areas.
 Air Pollution Around Schools Is Linked To Poorer Student Health And Academic Performance. Health Affairs. 30(5), 852 - 862.(2011).
Data from the long-running Framingham Heart Study has revealed that depression significantly increased the risk of developing dementia. Of the 125 people (13%) who were classified as having depression at the start of the study, 21.6% had developed dementia by the end of the study (17 years later). This compares to around 16.6% of those who weren’t depressed. When age, gender, education, homocysteine, and APOE gene status were taken into account, depressed participants had a more than 50% increased risk of developing dementia. Moreover, for each 10-point increase on the self-report scale used to measure depression (CES-D), there was a significant increase in the dementia risk. These findings, from one of the largest and longest population-based studies, should clarify the inconsistent results from earlier research.
There are several possible ways depression might increase the risk of dementia — for example, through the brain inflammation or the increased level of certain proteins that occurs during depression; or through the effects on lifestyle (reduced exercise, social engagement, poor diet).
 Depressive symptoms and risk of dementia: The Framingham Heart Study. Neurology. 75(1), 35 - 41.(2010).
A review of 35 studies published between 1991 and 2007 has found that depression does not always lead to cognitive impairment. Part of the variability in findings may be due to inconsistent measurement and diagnosis of depression. Processing speed was found to be the cognitive function most consistently affected by depression. Processing speed deficits can be helped by decreasing the amount of information to process at one time.
 Association between depression severity and neurocognitive function in major depressive disorder: A review and synthesis.. Neuropsychology. 24(1), 9 - 34.(2010).
Both diabetes and clinical depression are known to be risk factors for dementia. Now a study that tracked nearly 4000 diabetics over 5 years has found having both increased the risk 2.7-fold. Nearly 8% of the diabetics with major depression (36 of 455) developed dementia over the five years, compared to 4.8% of those with diabetes alone (163 of 3382). Those who developed dementia within 2 years of being diagnosed with depression were excluded. Depression is common among people who have diabetes.
 Comorbid Depression Is Associated with an Increased Risk of Dementia Diagnosis in Patients with Diabetes: A Prospective Cohort Study. Journal of General Internal Medicine. 25(5), 423 - 429.(2010).
Amnestic mild cognitive impairment often leads to Alzheimer's disease, but what predicts aMCI? A study involving 94 older adults has revealed that lower performance on tests measuring learning, in conjunction with either slower visuomotor processing speed or depressive symptoms, predicted the development of aMCI a year later with an accuracy of 80-100%. It is worth emphasizing that poor learning alone was not predictive in that time-frame, although one learning measure was predictive of aMCI two years later. Interestingly, neither gender nor possession of the ‘Alzheimer’s gene’ —long believed to be risk factors for mild cognitive impairment — had any substantial influence on later impairment.
 Hierarchical Cognitive and Psychosocial Predictors of Amnestic Mild Cognitive Impairment. Journal of the International Neuropsychological Society. 16(04), 721 - 729.(2010).
Older news items (pre-2010) brought over from the old website
Psychological distress, not depression, linked to increased risk of stroke
A study following 20,627 people for an average of 8.5 years has found that psychological distress was associated with an increased risk of stroke and that the risk of stroke increased the more distress the participants reported. This association remained the same regardless of cigarette smoking, systolic blood pressure, overall blood cholesterol, obesity, previous heart attack, diabetes, social class, education, high blood pressure treatment, family history of stroke and recent antidepressant medication use. However, there was no increased risk for people who had experienced an episode of major depression in the past year or at any point in their lifetime.
 Psychological distress, major depressive disorder, and risk of stroke. Neurology. 70(10), 788 - 794.(2008).
Depression increases risk of executive dysfunction in older people
A two-year study of more than 700 older adults (65 and older) has found that depression increased the risk of declining executive function (high-level mental processes, such a making decisions, organizing, planning and doing a series of things in sequence).
 Does Depression Precede or Follow Executive Dysfunction? Outcomes in Older Primary Care Patients. Am J Psychiatry. 164(8), 1221 - 1228.(2007).
Depressed older adults more likely to become cognitively impaired
A study involving 2,220 participants in the Cardiovascular Health Study, a longitudinal prospective study of adults 65 and older, has found that 19.7% of subjects with moderate to high depression developed mild cognitive impairment within six years, compared to 10% of subjects with no depressive symptoms and 13.3% of subjects with low depressive symptoms. There was no correlation between depression and vascular disease, although it has been hypothesized that vascular disease might lead to both depression and cognitive impairment by causing inadequate blood flow to different brain structures.
 Depressive Symptoms, Vascular Disease, and Mild Cognitive Impairment: Findings From the Cardiovascular Health Study. Arch Gen Psychiatry. 63(3), 273 - 279.(2006).
Treatable depression often accompanies mild memory loss
A large-scale study of older adults begun in 1989 has revealed that 43% of those with mild cognitive impairment had psychiatric symptoms (such as depression, irritability, loss of interest in activities, or changes in sleep or appetite) in the month before examination. Such symptoms are often shrugged off as emotional reactions to memory decline, but they may be due to changes in brain function, and may respond to treatment.
 Prevalence of Neuropsychiatric Symptoms in Dementia and Mild Cognitive Impairment: Results From the Cardiovascular Health Study. JAMA. 288(12), 1475 - 1483.(2002).