The rise in Mental Health Problems: a puzzle

Here’s a true modern puzzle for you: why is the rate of mental health problems, including depression, anxiety, and obesity, increasing in the US, Australia, urban China, and most Western countries?

Which mental health problems again? Depression, anxiety, and obesity are the big growth areas. And, yes, I view obesity as a mental health problem, ie the result of a lack of willpower.

Let me give you the quick stylised facts on these arising from the literature.

An authoritative paper on depression in 1989 said on the increase since WWII that

“Several recent, large epidemiologic and family studies suggest important temporal changes in the rates of major depression: an increase in the rates in the cohorts born after World War II; a decrease in the age of onset with an increase in the late teenaged and early adult years; an increase between 1960 and 1975 in the rates of depression for all ages; a persistent gender effect, with the risk of depression consistently two to three times higher among women than men across all adult ages; a persistent family effect, with the risk about two to three times higher in first-degree relatives as compared with controls; and the suggestion of a narrowing of the differential risk to men and women due to a greater increase in risk of depression among young men. These trends, drawn from studies using comparable methods and modern diagnostic criteria, are evident in the United States, Sweden, Germany, Canada, and New Zealand, but not in comparable studies conducted in Korea and Puerto Rico and of Mexican Americans living in the United States. These cohort changes cannot be fully attributed to artifacts of reporting, recall, mortality, or labeling and have implications for understanding the etiology of depression and for clinical practice.”

A recent 2011 paper on the US summarises the available evidence thus:

“Almost all of the available evidence suggests a sharp rise in anxiety, depression, and mental health issues among Western youth between the early 20th century and the early 1990s. Between the early 1990s and the present, more serious problems such as suicide and depression have receded in some data sets, whereas feeling overwhelmed and reporting psychosomatic complaints have continued to increase. Other indicators, such as anxiety, have remained at historically high levels but not continued to increase. This mixed pattern of results may be rooted in the increasing use of antidepressants and therapy and the improvement in some cultural indicators. However, the incidence of youth mental health problems remains unacceptably high.

Just a few generations ago, depression and suicide were considered afflictions of middle age. However, throughout the 1960s, 1970s, and 1980s, the average age of onset for depression moved downward (Klerman & Weissman, 1989), and the suicide rate for young people (aged 15–24, per 100,000 population) skyrocketed from 5.2 in 1960 to 13.3 in 1995 (U.S. Bureau of the Census, 2011). Numerous studies reported sharp increases in the lifetime prevalence of depression, including among adolescents and young adults (e.g., Lewinsohn, Rohde, Seeley, & Fischer, 1993). Only 1%–2% of Americans born before 1915 experienced a major depressive episode during their lifetimes, even though they lived through the Great Depression and two world wars. By the 1990s, the lifetime rate of major depression was 10 times higher—between 15% and 20%. Some studies put the figure closer to 50%. (Kessler et al., 1994; Wickramaratne, Weissman, Leaf, & Holford, 1989).”

So for depression in the US, we are talking about up to 50% of the population who will experience a bout of it, a ten-fold increase from the generation born in WWI. For anxiety, studies say that some 30-50% of the current generations in the US and Europe will be affected by some anxiety disorder or another in their life, again orders of magnitude higher than two generations ago.

For obesity, the same can be said: from being a problem that afflicted a couple of percent in 1900, we are fast approaching a situation where the majority of the population in the US is obese. This is already true for the 50 to 60 years of age population and rates in other western countries are on the rise too, showing no sign of a slow-down.

The role of medicine is interesting here: the effects of anxiety and depression seem to be kept manageable by medicines preventing the sufferers from committing suicide or becoming psychotic. The effects of obesity are similarly countered by medicines, through blood thinners, bypass operations, and the like. So whilst rates of mental health problems are at an all-time historical high, medicine is successful at reducing the impact on people’s lives.

Here is the puzzle: what on earth is going on here? On any objective measure, life is better now for the vast majority of the population than ever before. People are richer, live longer, run fewer risks, are surrounded by less violence and large shocks, and essentially have less to fear and be depressed about. Indeed, people are as happy now as ever, reflecting the fact that these are good times. Why then the increase in mental health problems in societies like the US, Australia and most of Europe?

Take just the obesity puzzle: One can basically out of hand reject the excuses most individuals give for their problems as being the reason. The rate of increase rules out any reasonable role for genetics. The fact that the poor suffer more from obesity, whilst it is cheaper to eat less and whilst food has always been cheap for the rich, rules out any obvious effect of the lower price of food or the availability of fast-food. The sustained increase over a long time rules out any story depending on some major current crisis. Like it or loath it, but it is clear that one must look at ‘cultural factors’ to have a hope of understanding what is going on.

A big hint comes from cross-national differences amongst rich countries, where things like wealth and food affordability dont differ much. As you can see here, the Anglo-Saxon countries, and then particularly the US, stands out. Whilst a third of adults in the US are now obese (with about 25% of Australian adults), only 4% of Koreans and Japanese are such, and in the more egalitarian Northern European countries (Sweden, Norway, Holland) rates are below 10%. The same holds for Italy and France, though rates in those countries too are quite a bit up from what they were 50 years ago. So your one major clue is that there are major unexplained differences over countries. Similar things hold for the other mental health problems.

Which cultural factors though and what underlies changes in these cultural factors? This is a wide-open and currently empty field in health economics. Your suggestions are thus greatly appreciated in the comment boxes!

Author: paulfrijters

Professor of Wellbeing and Economics at the London School of Economics, Centre for Economic Performance

26 thoughts on “The rise in Mental Health Problems: a puzzle”

  1. There’s some uninformed commentary in there, but also many good points.

    Some things to consider:

    1. Rates of psychiatric diagnosis have increased due to improved mental health care, so what we’re seeing isn’t an outbreak of mental illness, but a recognition of existing illness.

    2. Anxiety and depression can be controlled with medication, but the origin is with individuals externalising their locus of control. Too much is made of biochemical causes, because our model for diagnosis and treatment (and funding) is overwhelmingly biomedical.

    3. Despite the discouraging figures, mental illness is treated better now than at any point in history, and de-institutionalisation of people with chronic mental illness has largely been a success.


    1. “1. Rates of psychiatric diagnosis have increased due to improved mental health care, so what we’re seeing isn’t an outbreak of mental illness, but a recognition of existing illness.”

      I dont believe that explains the increase (though it is certainly part of it), and neither does the literature. As the first quoted study says on depression and anxiety, “These cohort changes cannot be fully attributed to artifacts of reporting, recall, mortality, or labeling”. So no, the increase is not fully explained by reporting and measurement, its real.

      Similarly, the increase in obesity has not come about from improvements in scales, and neither is there something particular about the scales in the US or Australia!

      Which uninformed commentary, btw? You mean my comment on obesity and willpower perhaps (on which I have written quite a bit over the years)? You can call that ‘unpopular’ and ‘unwelcome’ commentary, but certainly not uninformed! Indeed, you probably don’t know what I mean by willpower.


  2. I am puzzled that that you equate depression and anxiety with obesity, Paul. It is my understanding that depression and anxiety are much less under one’s control (on average) than obesity. I do agree that obesity has become a real problem (see and actually worse than what you indicate (now 28 percent of the adult population). Cultural factors definitely play a role. I would nominate the larger availability (literally and in terms of disposable income) of various temptations and the mistaken expectation that rational individuals are able to figure out what is good for them. Given the information tsunamis that we are flooded with dayin dayout that seems hardly a good assumption. Changing habits and life organization also contribute. See this article today in SMH:


    1. Hi Andreas,

      I am not equating anything, merely including obesity in the list of mental health problems.

      So you blame temptations? But rich people have always had more temptations. And dont the Koreans and Japanese have temptations?


      1. No I didn’t just blame temptations. I also mentioned the mistaken expectation that rational individuals are able to figure out what is good for them (which obviously is moderated by education and what not). And I mentioned that changing habits and life organization also contribute. Yes, rich people have possibly more temptations but on average that is probably counteracted by the fact that these people can afford healthier diets and that they are better educated (and hence are better in figuring out what is good for them). Yes, it is interesting to see that Korea and Japan have not nearly the same problem as western countries. I suspect that on average healthier diets are part of the story. At least that’s my impression from what little I know about these cultures.


  3. I doubt you’d say that people with clinical depression should stop being sad sacks and watch a funny movie to cheer themselves up. Depression advocacy groups have managed to educate Australians past that, but compulsive over-eaters still get branded as lazy and lacking willpower.

    It’s alarming that you so flippantly draw a direct comparison between depression diagnosis and eating disorders, as though the complexities in acknowledging depression are the same as noticing someone is obese.

    A good piece here:


    1. you are putting words into my mouth here, Sancho. What I am doing is calling the obesity increase a mental health issue, no more, no less.


  4. It is definitely a cultural thing. You might enjoy this paper about the ‘spread’ of obesity through social networks.

    Click to access 370.pdf

    I don’t think it’s an empty box as you say. Perhaps health economists need to catch up with epidemiologists.

    Bad habits spread through social networks and become normalised into culture. Why some countries and not others? Possibly because some other habits just happened to already dominate (a strong food culture that couldn’t easily be replaced by a fast food culture).

    The other interesting trends to note are the countries were obesity rates seem to have peaked – England, France, Italy, Spain (I assume Japan because the changes have been so small). If we are going to explain the obesity boom, we need some factor to explain the peak.


  5. I’m not sure what is causing the obesity epidemic in Australia and New Zealand. The rise of obesity in Canada and the US is largely a result of agricultural policies instituted in the 1930s by Bennett and Roosevelt that aimed to aid farmers. Fattening foods like maize and soybeans were heavily subsidized. Also, in the US, Prohibition wiped out a lot of restaurants with quality food, leaving the way for a fast food culture. Tyler Cowen explains how American food became so bad here:


    1. You believe the obesity increase is due to consumers being tricked into eating more calories by virtue of certain food items containing more calories than before? No free will in terms of what people eat at all?


      1. I believe that when you subsidize a behavior, you tend to get more of it. As the rate of obesity increases, it becomes less taboo. Also, I think that the higher rate of obesity among the poor is a result of both lower self-discipline and the lower opportunity cost of fast food. The poor still need to eat, and fast food is frequently cheaper than cooking. There are probably other factors, but I believe that these explain a good deal of the obesity epidemic.


  6. Tricked might be it.

    Foods that taste like they have particular nutrients, but which don’t have them, will sell well. People might eat a heavily processed food with plenty of additives and their taste buds feel like it is providing them with what their body needs. But probably it doesn’t, because the taste is only artificial flavours, or because key parts of the food have been stripped out. So, after they’ve eaten it, they soon feel like eating more of it. There might be feedback loops of people eating more of the food that tastes like it gives the body certain things because they’ve eaten those foods before and not got the nutrients they need. Companies may stumble onto these foods and keep producing them because they sell well, or they may intentionally create foods to be this way. Either way doesn’t really matter.

    A similar effect may occur with radio, TV, and computers. Broadcasting occupies people’s time with other people speaking, singing, dancing, etc. And in some ways it is much higher quality speaking and singing than people are traditionally used to. But, it isn’t real interaction and it maybe doesn’t meet people’s social needs as well as pre-broadcasting interaction did. People might feel like they need some time with friends, so they watch Friends on TV, or a panel show, or some fake reality thing or something. The whole point of commercial broadcasting is to attract attention so it can be sold to advertisers, and although the most effective way to do this is by showing people talking or singing (key elements of traditional social interaction), this type of talking and singing may well not give the body the social interaction it needs because it isn’t personal and they aren’t involved, and the body may end up showing symptoms of loneliness or anxiety or whatever else.

    English speaking countries form the biggest broadcasting market with the most money put into attracting people’s attention. Interestingly, northern European countries tend to watch those same shows in original language, but the rest of Europe dubs. Possibly broadcasts in a foreign language aren’t percieved as true social interaction by the brain, and people then spend time actually talking to each other. Maybe telly watching causes obesity and poor food the depression.

    Then there is transport, and the form that work takes, and a bunch more possibilities. There must be a lot of literature on this, but I think you’re right in that there are a lot of open questions.


  7. Bah, just legalise ‘shrooms. There’s no way someone can be depressed after that sort of trip!
    Daily use of anti-depressants and adderall constitute drug abuse, in my opinion.


  8. I am not sure how this discussion morphed into a discussion about obesity. But let us look at some obvious trends.

    The USA DSM has whether we like it or not, progressively over a number of years redefined psychiatric illnesses so that an increasing number of cases of various illnesses is inevitable. I am surprised that the discussion has not identified this.

    As for obesity – this is one of the greatest beat-ups of this decade. Of course obesity is more prevalent. But obesity is a function of kilojoules ingested vs kilojoules expended. Convince me that the the kilojoules ingested has actually changed. But I have absolute confidence that the kilojoules expended has dramatically changed. Sometimes the simplest answer is correct.


  9. The fact that in 1900 the most fattening food tended the be the most expensive, whereas now the opposite is the case, must surely be involved. I don’t think “will power” has changed at all – the “fat merchant” used to be a stereotype for a reason.

    Not to mention that the majority of the population was once engaged in physical labour, whereas now the wealthy pay to perform physical labour at gymnasiums. You didn’t need the “will power” to go for a run every day when you were working down pit. And of course, a proliferation of labour-saving devices has, entirely unsurprisingly, resulting in much labour being saved.


  10. Peter,

    the literature has identified the labeling issue alright, but its hard to put a number on the ‘drift’ from unidentified cases to identified ones. Plenty of evidence on the increase in kilojoules, btw. Just google for ‘size of portions over time’.

    It is always cheaper to eat less (or to share a portion with more people) so whilst costs might be a hindrance in the past, price cant be the only factor, and the fact that the poor are the heaviest speaks against any simple ‘affordability’ explanation. And its not really true that the fattening stuff was the most expensive in times gone by: offal, skin, lard, etc., were relatively cheap. Sure, luxury bonbons were very expensive, but there was plenty of cheap fat stuff around. Indeed, if i think of traditionally cheap Northern European food, I am thinking of very caloric stuff, such as fat-soaked bread (think of Yorkshire pudding or the Dutch variant ‘oliebol’).
    The issue of physical work is also not clear: the Japanese and Koreans have also stopped doing physical work but haven’t bloated up as much as us. They have compensated by keeping up exercise. So there is an element of an inability to keep up healthy habits involved.


  11. Have you thought about the possibility of there being a connection between gut flora and a whole host of mental and physical health problems? The fact that most of the body’s serotonin is produced in our gut, and also the fact that the countries you mention have highly processed foods which have very little nutritional value. After all, the old adage says you are what you eat…


    1. Hi Jane,

      the ‘its all chemical’ explanation has crossed people’s mind, though I think it fair to say you dont find many adherents of it. Whilst not discounting the possibility, it comes with the following problems:
      1. If there was any ‘easy’ chemical issue then of course some food supplement or other would be expected to ‘solve’ the detrimental health effects. Despite billions of dollars that could be made by such a wonder pill, the industry frantically looking for it hasn’t found it yet. It makes one doubt that its ‘just chemical’ in the first place.
      2. Some indicators of mental abilities actually go up over time, such as the rise in average IQs (the Flyn effect). if there was something in our water or normal diet doing us mental harm, it seems unlikely that it wouldn’t also show up in IQs.

      So if its chemical it has so far evaded detection despite pretty hefty incentives and lots of random experimentation (think of all the wonder diets) trying to find it.


  12. Hi Paul, that’s interesting as I thought I saw an article the other day saying that we had lost something like 17 IQ points since the Victorian age, but will have to search to find that link. I was alluding to probiotics when I mentioned gut flora, so not necessarily ‘chemical’ but definintely a counter balance to the huge amount of antibiotics we are all prescribed by our GPs during our lifetime, as well as the preventative antibiotics routinely fed to livestock. Also, the amount of processed food we eat (which has been stripped of nutrients) as opposed to real, whole food which used to be prepared from scratch every day. Combine that then with the massive amount of animal meat we eat nowadays, compared with post war where meat was definitely more scare a commodity. In fact, the countries you cite which don’t have as much as an obesity problem (Japan, Korea, Italy) have very proud cusines and a large cultural factor surrounding their food consumption. I lived in Italy for 10 years and only saw a couple of MacDonalds in all that time. Meat in general was also far more expensive and used much more sparingly. (The secret to a decent ragu’ sauce is only using a handful of minced meat, not like our version of spag bol which is essentially mince on top of pasta.)
    So I think a combination of eating habits together with dodgy food multinationals selling us packaged crap is definitely a huge factor in obesity. And if you’ve ever carried too much weight, you know it makes you miserable!


    1. The IQ increase is pretty certain (I just did a book review on an IQ study), though of course open to various interpretations.

      I dont think the ‘stripped of nutrients’ story is all that plausible because we’d only need a supplementary pill of vitamins and other stuff if that was all it took. I doubt that if we started to mandate a minimum level of vitamins in hamburgers that we’d see any change in obesity levels!

      The meat story is also suspect: there have been various cultures and historical times in which meat was a staple good for some groups. Just think of the eskimos who had little else to eat in the frozen north but fish and seals, or the nobility in the middle ages who could afford a meat-rich diet. They were (probably) not as obese as we are now. So whilst you are clearly right that meat makes a calorie-rich diet, we are probably more looking at the result rather than the cause of greater appetites. Indeed, there are now diets on the market that work on an ‘only meat’ basis! Not that I believe in them, of course, but it does make it unlikely that the meat-story will get us very far.

      I find the ‘blame the industry for the supplements’ argument a little suspect too. Plenty of ‘packaged and processed’ food in Japan and Korea too, simply more nutritional and less caloric. Industry provides what people will buy, so why have food habits changed for the worst in some places? You will find that the salad bars in fast-food restaurants is not very popular.

      As a tv-comedian once wisely said about the importance of demand when it came to explaining fast-food supply: ‘you dont make friends with salad’…..


  13. Hmmmm. I am not qualified to comment clinically. But I do eat. I do shop for a family of six. I do encourage healthy living. What I see and hear everyday, is “behaviour” We eat first and think second. Then we MAY “weigh and measure” our choice. ( behaviour). Clearly the time frame between these behaviours have become extended. The more distance there is between eating, thinking and evaluating; the larger our waistlines, the larger the effects, and the larger the time frame to reverse the behaviour. creating a “new norm” is very difficult indeed. I have read all the posts with much interest. Thanks to you all.


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