Richard G. Petty, MD

Mold, Dampness and Depression

It matters where you live.

I have lived or stayed in many countries, and there is no doubt that some places are a lot more congenial than others. I don’t just mean a beach in Thailand compared with the North of Scotland in winter. Some places just make you feel better. There are many physical, psychological, social and subtle reasons, but here is a relatively new one.

There is an important paper in this month’s issue of the American Journal of Public Health looking at the possibility of a link between dampness and mold in the home and clinical depression.

Molds are fungi that are found in many environments but most of them grow best in warm, damp, and humid conditions. Therefore, dwellings that have problems with damp also commonly have problems with mold. Although the physical health consequences of living in a damp and moldy dwelling are quite well known, the effect of living in such an environment on mental health has not.

Some of the known health problems associated with high levels of airborne mold spores include:

  • Allergic reactions
  • Asthma
  • Irritations of the eyes, nose and throat
  • Sinus congestion and other respiratory problems
  • In people with with weakened immune systems, inhaled mold spores may germinate, attaching to cells along the respiratory tract
  • Immunocompromised individuals exposed to high levels of
    mold may get a systemic fungal
  • Infections of the digestive tract, lung and skin

The researchers used survey data from 8 European cities. They created a dampness and mold score from resident- and inspector-reported data. Depression was assessed using a validated index of depressive symptoms.

The results showed that dampness and mold were associated with depression, independent of individual and housing characteristics. This association was independently mediated by perception of control over one’s home and by physical health.

This link is most likely because of the psychological and physiological consequences of living in poor housing conditions. But there could also be a direct pathological effect of mold itself.

Birth Order, Social Order and Intelligence

For many decades, experts have disagreed about the impact of birth order on intellect, achievement and emotional and cognitive skills.

Some have claimed that first-born children get more undivided attention from their parents and so develop faster and become more cognitively competent.

Others have claimed that birth order might have an impact because of differences in the womb before birth. The idea was that with each subsequent pregnancy the mother produces higher and higher levels of antibodies that may attack the fetal brain.

Other researchers claim that the relationship between birth order and intelligence is false, having been biased by family size. Historically there has been a tendency couples with lower IQs to have more children than couples with higher IQs. But that is also hard to support: there are many cultures and religions in which high IQ couples have many children.

Three years ago, Dalton Conley, a sociologist from New York University and director of the Center for Advanced Social Science Research published a fascinating book, The Pecking Order, in which he used data from the U.S. Census, the General Social Census Survey conducted at the University of Chicago over the last thirty years, as well as a prospective study launched in 1968, at the University of Michigan. He came to the conclusion that siblings diverge widely in social status, wealth and education. We can all remember examples in the news: of a President with a drug using brother and a professor whose brother was a convict. There are scores of other cases like these.

In Dalton’s model, there are genetic, social and birth order reasons for these family inequalities. Most families establish a hierarchy that predicts a child’s success and role within a family. Where you are in that hierarchy is only partly determined by birth order. Dalton argued that what really matters is family size, parental time and attention, and how much of the family’s financial resources are available for the child. His research showed that no single factor could predict success or failure in life. That makes good sense, though when we look at family hierarchies there is likely a strong cultural and ethnic factor at play. In some cultures first-born boys still receive a great deal more favoritism than the other children.

Now a Norwegian team has reported in the journal Science that first born children and those who had lost older siblings and had thereby become the eldest, scored higher on standard tests of intelligence. The IQ difference that they found in their study groups was small but significant.

The link was found by Professor Petter Kristensen at the National Institute of Occupational Health in Oslo, and Tor Bjerkedal at the Norwegian Armed Forces Medical Service who looked at more than 250,000 male Norwegian conscripts.

What they found in this large all male group was that it is the son’s social position in a family rather than his biological position that counts toward his intelligence.

For example, if a man was born third but then lost an elder sibling in early childhood, he would normally be raised as if had been born second. And his IQ as an adult would tend to be close to that of “genuine” second-borns.

It is going to be interesting to see whether there is a similar effect in girls, since they tend to grow up more quickly than boys.

The fact that the death of an older sibling “moves the child up” the IQ rankings is against something going on in the womb.

There are several possible reasons for this effect. More mature children often tend to become a surrogate parent. And because he or she is still young they will tend to become very conscientious, mature and self-disciplined. You have probably seen or known of a child who had to do a lot of growing up very quickly after the death of, or abandonment by, a parent.

Another possibility is that a first-born gets smarter because he or she tutors the younger siblings.

A complicating factor in this research is when a child “moves up” because of the death of an older sibling, the shock of losing a child may lead the family to expend even more care and attention on the surviving children, particular those most likely to be able to take over if anything happens to the parents.

And the other point I something that I have discussed before. There are genes that predispose you to having a certain type and degree of intelligence. But social and environmental factors continue to have a powerful impact.

I just read an article in which the parents of some mentally ill people were declaring that new research on the social triggers to mental illness was a waste of time, and that the “Answer” must be biological.

It is rarely that simple: genes, epigenetic factors, nutrition, personal experience and the social and emotional environment all need to be put into the mix if we want to understand why someone is the way that they are, and how we can help them to fulfill their potential.

Race and Diabetes

It’s another one of those, “Everyone knows that…” facts. For forty years we have all been taught that some ethnic groups are at higher risk of developing insulin resistance and type 2 diabetes mellitus. So now “everyone knows that” African Americans, Native Americans and people from the Indian sub-continent are all genetically predisposed to these medical maladies.

Now it looks as if “everyone” might have been wrong.

James Neel first proposed the theory of the “thrifty genotype” in 1962. He suggested that cycles of feast and famine early in human history created a gene that helps the body use scarce nutrients – a gene that leads to obesity and diabetes in sedentary modern populations with ready and continuous access to food.

Several months ago I pointed out some of the problems with the thrifty genotype theory, and why many of us have become more convinced about the concept of the “thrifty phenotype.” I have many friends, colleagues and former trainees who have dedicated themselves to hunting for diabetes genes. As early as the mid-1980s I was worried that they were going to vanish down a rabbit hole.

It seemed illogical that a gene or genes could “explain” an illness that was, until recently, very rare. It would have to be a gene that was somehow switched on and off by diet or some other environmental factors. It is certainly possible but seemed implausible, given that there are dozens of genes designed to control food intake and metabolism. But my friends the gene jockeys had the louder voice, and it was good for them to see what they could find. Now, twenty years later, more than 250 genes have been studied as possible causes of type 2 diabetes, but together these genes explain less than 1 percent of diabetes prevalence worldwide.

There is an interesting piece of research published in the journal Perspectives in Biology and Medicine by a team of researchers from the United States and Australia, that supports what I was saying. The study was co-authored by UC Irvine anthropologist Michael Montoya, an anthropologist at the University of California at Irvine, together with an epidemiologist and population geneticist. Together they analyzed existing genetic studies published across a variety of disciplines. The team found no evidence to support the thrifty genotype theory.

They also found that in most existing studies of the suspected genes that contribute to diabetes in ethnic minorities, researchers had failed to control for the potential impact of social and environmental factors. If those factors are taken into account, other factors – such as poverty, housing segregation or poor diet – were stronger indicators of diabetes than genes.

As Montoya said,

“Our study challenges the presumption that Native American, Mexican American, African American, Australian Aborigine, or other indigenous groups are genetically prone to diabetes because the evidence demonstrates that higher rates of diabetes across population groups can be explained by non-genetic factors alone. Our study shows that by focusing on genes, researchers miss the more significant and alterable environmental causes of diabetes.”

One of Montoya’s co-authors, Stephanie Malia Fullerton, a population geneticist and bioethicist at the University of Washington added,

“When it comes to diabetes, we’re finding that genes are no more important for ethnic minorities than for anyone else.”

This new critique of genetic and ethnic studies will need to be replicated, and it is a little bit of a surprise that such important work was published in Perspectives rather than one of the journals dedicated to epidemiology.

I have no inside knowledge about why the study was published where it was. But it often happens that it can be very difficult to get new research published if it contradicts the mainstream. There have been examples of experts squashing data that contradicts their own, but it is uncommon. Most of the time the difficulty in getting revolutionary new data published is not because of some conspiracy, but because any kind of evidence, particularly if it is radically different, attracts the most concentrated scrutiny by independent reviewers.

If this new data analysis is confirmed, it is going to mean a radical re-think about the ways in which we screen, manage and advise people from different ethnic groups.

It also confirms something that I’ve said a hundred times: Biology is Not Destiny.

Social Adversity and Schizophrenia

People who are interested in the interaction of genes, environment, brain and mental illness might be interested to look at a brief article posted over at the Psychiatric Resource Forum.

The article summarizes some very important new data on social adversity and the subsequent dvelopment of major mental illness. The research has been looking at a huge puzzle: why are serious mental illnesses so much more common in Afro-Caribbeans and Africans living in England and other parts of Western Europe? It was initially thought that it might all be due to over-diagnosis, but with deatialed work done in England, the Caribbean and Africa it has now become clear that that isn’t it.

There may be a contribution from vitamin D deficiency: dark skinned people who are recent immigrants cannot make as much in their skin as they need. But that is not a cause but a potential contrbutor. That being said I am going to have something more to say about causality in medicine in a post in the next day or two.

A second line of research has identified some key brain structures that if abnormal, dramatically increase the change that a "high risk" person will develop schizophrenia. By "high risk" we mean a significant family history of the illness.

This is important material and represents a major step forward in our understanding of major mental illness and a move away from the medical model that has dominated so much of psychiatry over the last 30 years.

Optimism and Pessimism

It is sometimes very disheartening to read articles that are probably well intentioned, but in which the writer hasn’t done the most basic research.

I was just sent an article on optimism and pessimism, in which the writer extols the benefits of developing an optimistic outlook on life. And yes, it’s nice to be optimistic, but he – at least I think that it’s a he – makes several significant errors.

He gives examples of several well-known people who were supposed to have attained great things by being optimistic rather than realistic. He has clearly not studied the lives Thomas Edison or Henry Ford in any detail. Or Winston Churchill, Mother Teresa or Ted Turner.

He then says that optimism cannot be measured. Yes it can, there are many validated rating instruments. There is also a lot of research on the relationship between optimism, pessimism, temperament and cognitive and personality styles.

He goes on to say that you can learn to have an optimistic outlook on life. That is only half true. There are well-known genetic predispositions to optimism and pessimism. I’ve also written about recent work from Finland that makes it clear that it is very difficult to develop an optimistic mind set if you spent your childhood in a low socioeconomic status family. Special techniques may be needed to help people who were disadvantaged in childhood.

The idea that you can achieve anything by just “thinking it,” is not just wrong but it leads to some people feeling inadequate because they cannot generate enthusiasm and optimism. I have seen countless people feel guilty because they could not feel happy and optimistic the way that the motivational speaker told them to!

An un-researched and unbalanced article does more harm than good. It’s no good saying that it wasn’t meant to be scientific: you, as a reader, deserve better than some generalized nostrums based on wishful thinking. If someone recommends something, you need to know whether you can rely on what you are being told, or if it is just an unsubstantiated opinion. If it’s just an opinion, that’s fine, but you need to be told that, and why you can rely on that opinion, or why the writer has chosen to disregard research and previous experience.

So are you stuck with you genes and your upbringing? No you are not. But it is important to know if you are one of the people who do better with negative cognitions. It is well known in psychology that some people do much better with a constant negative outlook on life. In fact a psychologist – Julie Norem – wrote a first rate book on the subject entitled The Positive Power of Negative Thinking: Using Defensive Pessimism to Harness Anxiety and Perform at Your Peak.

There are techniques from cognitive therapy that can help change a person’s outlook and the newer technique – Attachment and Commitment Therapy – teaches ways of detaching from negative and pessimistic cognitions, rather than trying to stick a smiley face on them.

Best of all are the techniques of Integrated Medicine, that help attitudinal problems with a combination of highly individualized physical, psychological, social, subtle and spiritual techniques.

“If wishes were horses, then beggars would ride.”–Unknown Author

Temperament, Depression, Class and Resilience

Within the first few weeks of life, infants show marked individual differences in their level of activity, their responsiveness to change in the environment and their irritability. Some clearly enjoy being touched and mold their bodies to the person holding them, while other stiffen and squirm and do less to adjust their bodies to another person. These mood-related personality characteristics are called temperaments. There is some evidence that temperament is one of the basic building blocks of the personality. Temperament appears to consist of inborn traits, but they can be modified by parental contact: there is actually a reciprocal relationship between child and parent. The child modifies the behavior and attitude of the parent.

It is commonly said that a child’s temperament is as fixed as handedness or eye color, but this is inaccurate: we have overwhelming evidence that temperament can be changed by environmental influences. This makes sense. In Healing, Meaning and Purpose, we discuss the implications of the new findings about genes in the brain: they do not so much determine behavior as predispose you to the way that you will handle the environment. An important questions is just how plastic is human temperament? To what extent can you overcome your genetic programming and early rearing? Some recent research has indicated that the environment of the first three years of life is not as critical to later development as we used to believe. But I think that it’s dangerous to read too much into this research. Early emotional deprivation may leave the deepest scars and also be associated with physical deprivation. If a developing brain is deprived of key nutrients, it is difficult to catch up later.

More and more research is finding key genes that contribute to temperament. There is important evidence from animal research that the temperament of infant female rats can predict life span in those who develop spontaneous tumors. It is difficult to extrapolate from that to humans, but it is a further demonstration of the incredibly subtle interactions between genes, the environment, behavior and physical illness.

Some important recent research has examined the impact of temperament on the clinical features of bipolar disorder and of ADHD and autistic spectrum disorders. As expected, people with ADHD reported high levels of novelty seeking and high levels of harm avoidance. Patients with autism spectrum disorders were low on measures of novelty seeking, they had little dependence on rewards and high harm avoidance. Cluster B personality disorders, the dramatic, emotional, or erratic disorders ones (antisocial, borderline, narcissistic and histrionic), were more common in people with ADHD and the other clusters A and C were more common in autistic spectrum disorders. This tells us that these tow clinical conditions can have some specific effects on the structure of temperament, and on the risk of developing specific personality disorders.

In a new study in next month’s issue of the Journal of Personality, Kati Heinonen and colleagues from the Department of Psychology at University of Helsinki, have found a correlation between adult pessimism and childhood temperament in low socioeconomic status (SES) families. It is no surprise to learn that children raised in higher socioeconomic groups have a more optimistic outlook on life. But this is what is interesting, and the thing that will launch a great many more studies. It was discovered that the effect of childhood socioeconomic status on pessimism tended to remain the same despite opportunities for socioeconomic fluidity. A person from a low SES childhood who moved upwards in status was less likely to be optimistic as an adult than someone from a high SES childhood who remained in a high SES environment. The inverse also held true, as people from a high SES childhood who moved downwards in socioeconomic status were more optimistic than those who remained in low SES. This indicates that children who had the chance to develop coping strategies during childhood and subsequently developed a sense of mastery and control that protected them in adulthood from the adverse effects of lower SES. By contrast children from lower SES backgrounds who are subsequently upwardly mobile may not have had the opportunities to develop those psychological resources. They are thus unable to benefit as much as possible from later experiences of success.

We already know that pessimism is related to physical and mental health, so this new study provides a critical link between socioeconomic status and long-term outcome. This is essential information for policy makers and for parents interested in helping children develop more effective coping strategies.

This research really proves that some of the excessive optimism of the self-help movement can sometimes be misplaced: just wanting something to be different does not make it so. If you had a lousy up-bringing in impoverished surroundings, it will make it more difficult to bounce back and learn essential coping skills.

More difficult, but not impossible.

Research on resilience has provided us with a great deal of information about developing mastery and coping skills in the face of being in a low SES, and we shall return to some of that work in the near future.

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