Why we need to get better at critiquing psychiatric diagnosis

This piece is based on my talk to the UCL conference ‘The Role of Diagnosis in Clinical Psychology’. It was aimed at an audience of clinical psychologists but should be of interest more widely.

I’ve been a longterm critic of psychiatric diagnoses but I’ve become increasingly frustrated by the myths and over-generalisations that get repeated and recycled in the diagnosis debate.

So, in this post, I want to tackle some of these before going on to suggest how we can critique diagnosis more effectively. I’m going to be referencing the DSM-5 but the examples I mention apply more widely.

“There are no biological tests for psychiatric diagnoses”

“The failure of decades of basic science research to reveal any specific biological or psychological marker that identifies a psychiatric diagnosis is well recognised” wrote Sami Timini in the International Journal of Clinical and Health Psychology. “Scientists have not identified a biological cause of, or even a reliable biomarker for, any mental disorder” claimed Brett Deacon in Clinical Psychology Review. “Indeed”, he continued “not one biological test appears as a diagnostic criterion in the current DSM-IV-TR or in the proposed criteria sets for the forthcoming DSM-5”. Jay Watts writing in The Guardian states that “These categories cannot be verified with objective tests”.

Actually there are very few DSM diagnoses for which biological tests are entirely irrelevant. Most use medical tests for differential diagnosis (excluding other causes), some DSM diagnoses require them as one of a number of criteria, and a handful are entirely based on biological tests. You can see this for yourself if you take the radical scientific step of opening the DSM-5 and reading what it actually says.

There are some DSM diagnoses (the minority) for which biological tests are entirely irrelevant. Body dysmorphic disorder (p242), for example, a diagnosis that describes where people become overwhelmed with the idea that a part of their body is misshapen or unattractive, is purely based on reported experiences and behaviour. No other criteria are required or relevant.

For most common DSM diagnoses, biological tests are relevant but for the purpose of excluding other causes. For example, in many DSM diagnoses there is a general exclusion that the symptoms must be not attributable to the physiological effects of a substance or another medical condition (this appears in schizophrenia, OCD, generalized anxiety disorder and many many others). On occasion, very specific biological tests are mentioned. For example, to make a confident diagnosis of panic disorder (p208), the DSM-5 recommends testing serum calcium levels to exclude hyperparathyroidism – which can produce similar symptoms.

Additionally, there are a range of DSM diagnoses for which biomedical tests make up one or more of the formally listed criteria but aren’t essential to make the diagnosis. The DSM diagnosis of narcolepsy (p372) is one example, which has two such criteria: “Hypocretin deficiency, as measured by cerebrospinal fluid (CSF) hypocretin-1 immunoreactivity values of one-third or less of those obtained in healthy subjects using the same assay, or 110 pg/mL or less” and polysomnography showing REM sleep latency of 15 minutes or less. Several other diagnoses work along these lines – where a biomedical tests results are listed but are not necessary to make the diagnosis: the substance/medication-induced mental disorders, delirium, neuroleptic malignant syndrome, neurocognitive disorders, and so on.

There are also a range of DSM diagnoses that are not solely based on biomedical tests but for which positive test results are necessary for the diagnosis. Anorexia nervosa (p338) is the most obvious, which requires the person to have a BMI of less than 17, but this applies to various sleep disorders (e.g. REM sleep disorder which requires a positive polysomnography or actigraphy finding) and some disorders due to other medical conditions. For example, neurocognitive disorder due to prion disease (p634) requires a brain scan or blood test.

There are some DSM diagnoses which are based exclusively on biological test results. These are a number of sleep disorders (obstructive sleep apnea hypopnea, central sleep apnea and sleep-related hypoventilation, all diagnosed with polysomnography).

“Psychiatric diagnoses ‘label distress'”

The DSM, wrote Peter Kinderman and colleagues in Evidence-Based Mental Health is a “franchise for the classification and diagnosis of human distress”. The “ICD is based on exactly the same principles as the DSM” argued Lucy Johnstone, “Both systems are about describing people’s distress in terms of medical diagnosis”

In reality, some psychiatric diagnoses do classify distress, some don’t.

Here is a common criterion in many DSM diagnoses: “The symptoms cause clinical significant distress or impairment in social, occupational or other important areas of functioning”

The theory behind this is that some experiences or behaviours are not considered of medical interest unless they cause you problems, which is defined as distress or impairment. Note however, that it is one or the other. It is still possible to be diagnosed if you’re not distressed but still find these experiences or behaviours get in the way of everyday life.

However, there are a whole range of DSM diagnoses for which distress plays no part in making the diagnosis.

Here is a non-exhaustive list: Schizophrenia, Tic Disorders, Delusional Disorder, Developmental Coordination Disorder, Brief Psychotic Disorder, Schizophreniform Disorder, Manic Episode, Hypomanic Episode, Schizoid Personality Disorder, Antisocial Personality Disorder, and so on. There are many more.

Does the DSM ‘label distress’? Sometimes. Do all psychiatric diagnoses? No they don’t.

“Psychiatric diagnoses are not reliable”

The graph below shows the inter-rater reliability results from the DSM-5 field trial study. They use a statistical test called Cohen’s Kappa to test how well two independent psychiatrists, assessing the same individual through an open interview, agree on a particular diagnosis. A score above 0.8 is usually considered gold standard, they rate anything above 0.6 in the acceptable range.

The results are atrocious. This graph is often touted as evidence that psychiatric diagnoses can’t be made reliably.

However, here are the results from a study that tested diagnostic agreement on a range of DSM-5 diagnoses when psychiatrists used a structured interview assessment. Look down the ‘κ’ column for the reliability results. Suddenly they are much better and are all within the acceptable to excellent range.

This is well-known in mental health and medicine as a whole. If you want consistency, you have to use a structured assessment method.

While we’re here, let’s tackle an implicit assumption that underlies many of these critiques: supposedly, psychiatric diagnoses are fuzzy and unreliable, whereas the rest of medicine makes cut-and-dry diagnoses based on unequivocal medical test results.

This is a myth based on ignorance about how medical diagnoses are made – almost all involve human judgement. Just look at the between-doctor agreement results for some diagnoses in the rest of medicine (which include the use of biomedical tests):

Diagnosis of infection at the site of surgery (0.44), features of spinal tumours (0.19 – 0.59), bone fractures in children (0.71), rectal bleeding (0.42), paediatric stroke (0.61), osteoarthritis in the hand (0.60 – 0.82). There are many more examples in the medical literature which you can see for yourself.

The reliability of DSM-5 diagnoses is typically poor for ‘off the top of the head’ diagnosis but this can be markedly improved by using a formal diagnostic assessment. This doesn’t seem to be any different from the rest of medicine.

“Psychiatric diagnoses are not valid because they are decided by a committee”

I’m sorry to break it to you, but all medical diagnoses are decided by committee.

These committees shift the boundaries, revise, reject and resurrect diagnoses across medicine. The European Society of Cardiology revise the diagnostic criteria for heart failure and related problems on a yearly basis. The International League Against Epilepsy revise their diagnoses of different epilepsies frequently – they just published their revised manual earlier this year. In 2014 they broadened the diagnostic criteria for epilepsy meaning more people are now classified as having epilepsy. Nothing changed in people’s brains, they just made a group decision.

In fact, if you look at the medical literature, it’s abuzz with committees deciding, revising and rejecting diagnostic criteria for medical problems across the board.

Humans are not cut-and-dry. Neither are most illnesses, diseases and injuries, and decisions about what a particular diagnosis should include is always a trade-off between measurement accuracy, suffering, outcome, and the potential benefits of intervention. This gets revised by a committee who examine the best evidence and come to a consensus on what should count as a medically-relevant problem.

These committees aren’t perfect. They sometimes suffer from fads and group think, and pharmaceutical industry conflicts of interest are a constant concern, but the fact that a committee decides a diagnosis does not make it invalid. I would argue that psychiatry is more prone to fads and pressure from pharmaceutical company interests than some other areas of medicine although it’s probably not the worst (surgery is notoriously bad in this regard). However, having a diagnosis decided by committee doesn’t make it invalid. Actually, on balance, it’s probably the least worst way of doing it.

“Psychiatric diagnoses are not valid because they’re based on experience, behaviour or value judgements”

We’ve discussed above how DSM diagnoses rely on medical tests to varying degrees. But the flip side of this, is that there are many non-psychiatric diagnoses which are also only based on classifying experience and/or behaviour. If you think this makes a diagnosis invalid or ‘not a real illness’ I look forward to your forthcoming campaigning to remove the diagnoses of tinnitus, sensory loss, many pain syndromes, headache, vertigo and the primary dystonias, for example.

To complicate things further, we know some diseases have a clear basis in terms of tissue damage but the diagnosis is purely based on experience and/or behaviour. The diagnosis of Parkinson’s disease, for example, is made this way and there are no biomedical tests that confirm the condition, despite the fact that studies have shown it occurs due to a breakdown of dopamine neurons in the nigrostriatal pathway of the brain.

At this point, someone usually says “but no one doubts that HIV or tuberculosis are diseases, whereas psychiatric diagnosis involves arbitrary decisions about what is considered pathological”. Cranks aside, the first part is true. It’s widely accepted – rightly so – that HIV and tuberculosis are diseases. However, it’s interesting how many critics of psychiatric diagnosis seem to have infectious diseases as their comparison for what constitutes a ‘genuine medical condition’ when infectious diseases are only a small minority of the diagnoses in medicine.

Even here though, subjectivity still plays a part. Rather than focusing on a single viral or bacterial infection, think of all viruses and bacteria. Now ask, which should be classified as diseases? This is not as cut-and-dry as you might think because humans are awash with viruses and bacteria, some helpful, some unhelpful, some irrelevant to our well-being. Ed Yong’s book I Contain Multitudes is brilliant on this if you want to know more about the massive complexity of our microbiome and how it relates to our well-being.

So the question for infectious disease experts is at what point does an unhelpful virus or bacteria become a disease? This involves making judgements about what should be considered a ‘negative effect’. Some are easy calls to make – mortality statistics are a fairly good yardstick. No one’s argued over the status of Ebola as a disease. But some cases are not so clear. In fact, the criteria for what constitutes a disease, formally discussed as how to classify the pathogenicity of microorganisms, can be found as a lively debate in the medical literature.

So all diagnoses in medicine involve a consensus judgement about what counts as ‘bad for us’. There is no biological test that which can answer this question in all cases. Value judgements are certainly more common in psychiatry than infectious diseases but probably less so than in plastic surgery, but no diagnosis is value-free.

“Psychiatric diagnosis isn’t valid because of the following reasons…”

Debating the validity of diagnoses is a good thing. In fact, it’s essential we do it. Lots of DSM diagnoses, as I’ve argued before, poorly predict outcome, and sometimes barely hang together conceptually. But there is no general criticism that applies to all psychiatric diagnoses. Rather than going through all the diagnoses in detail, look at the following list of DSM-5 diagnoses and ask yourself whether the same commonly made criticisms about ‘psychiatric diagnosis’ could be applied to them all:

Tourette’s syndrome, Insomnia, Erectile Disorder, Schizophrenia, Bipolar, Autism, Dyslexia, Stuttering, Enuerisis, Catatonia, PTSD, Pica, Sleep Apnea, Pyromania, Medication-Induced Acute Dystonia, Intermittent Explosive Disorder

Does psychiatric diagnosis medicalise distress arising from social hardship? Hard to see how this applies to stuttering and Tourette’s syndrome. Is psychiatric diagnosis used to oppress people who behave differently? If this applies to sleep apnea, I must have missed the protests. Does psychiatric diagnosis privilege biomedical explanations? I’m not sure this applies to PTSD.

There are many good critiques on the validity of specific psychiatric diagnoses, it’s impossible to see how they apply to all diagnoses.

How can we criticise psychiatric diagnosis better?

I want to make clear here that I’m not a ‘defender’ of psychiatric diagnosis. On a personal basis, I’m happy for people to use whatever framework they find useful to understand their own experiences. On a scientific basis, some diagnoses seem reasonable but many are a really poor guide to human nature and its challenges. For example, I would agree with other psychosis researchers that the days of schizophrenia being a useful diagnosis are numbered. By the way, this is not a particularly radical position – it has been one of the major pillars of the science of cognitive neuropsychiatry since it was founded.

However, I would like to think I am a defender of actually engaging with what you’re criticising. So here’s how I think we could move the diagnosis debate on.

Firstly, RTFM. Read the fucking manual. I’m sorry, but I’ve got no time for criticisms that can be refuted simply by looking at the thing you’re criticising. Saying there are no biological tests for DSM diagnoses is embarrassing when some are listed in the manual. Saying the DSM is about ‘labelling distress’ when many DSM diagnoses do not will get nothing more than an eye roll from me.

Secondly, we need be explicit about what we’re criticising. If someone is criticising ‘psychiatric diagnosis’ as a whole, they’re almost certainly talking nonsense because it’s a massively diverse field. Our criticisms about medicalisation, poor predictive validity and biomedical privilege may apply very well to schizophrenia, but they make little sense when we’re talking about sleep apnea or stuttering. Diagnosis can really only be coherently criticised on a case by case basis or where you have demonstrated that a particular group of diagnoses share particular characteristics – but you have to establish this first.

As an aside, restricting our criticisms to ‘functional psychiatric diagnosis’ will not suddenly make these arguments coherent. ‘Functional psychiatric diagnoses’ include Tourette’s syndrome, stuttering, dyslexia, erectile disorder, enuerisis, pica and insomnia to name but a few. Throwing them in front of the same critical cross-hairs as borderline personality disorder makes no sense. I did a whole talk on this if you want to check it out.

Thirdly, let’s stop pretending this isn’t about power and inter-professional rivalries. Many people have written very lucidly about how diagnosis is one of the supporting pillars in the power structure of psychiatry. This is true. The whole point of structural analysis is that concept, practice and power are intertwined. We criticise diagnosis, we are attacking the social power of psychiatry. This is not a reason to avoid it, and doesn’t mean this is the primary motivation, but we need to be aware of what we’re doing. Pretending we’re criticising diagnosis but not taking a swing at psychiatry is like calling someone ugly but saying it’s nothing against them personally. We should be working for a better and more equitable approach to mental health – and that includes respectful and conscious awareness of the wider implications of our actions.

Also, let’s not pretend psychology isn’t full of classifications. Just because they’re not published by the APA, doesn’t mean they’re any more valid or have the potential to be any more damaging (or indeed, the potential to be any more liberating). And if you are really against classifying experience and behaviour in any way, I recommend you stop using language, because it relies on exactly this.

Most importantly though, this really isn’t about us as professionals. The people most affected by these debates are ultimately people with mental health problems, often with the least power to make a difference to what’s happening. This needs to change and we need to respect and include a diversity of opinion and lived experience concerning the value of diagnosis. Some people say that having a psychiatric diagnosis is like someone holding their head below water, others say it’s the only thing that keeps their head above water. We need a system that supports everyone.

Finally, I think we’d be better off if we treated diagnoses more like tools, and less like ideologies. They may be more or less helpful in different situations, and at different times, and for different people, and we should strive to ensure a range of options are available to people who need them, both diagnostic and non-diagnostic. Each tested and refined with science, meaning, lived experience, and ethics.

Serendipity in psychological research

micDorothy Bishop has an excellent post ‘Ten serendipitous findings in psychology’, in which she lists ten celebrated discoveries which occurred by happy accident.

Each discovery is interesting in itself, but Prof Bishop puts the discoveries in the context of the recent discussion about preregistration (declaring in advance what you are looking for and how you’ll look). Does preregistration hinder serendipity? Absolutely not says Bishop, not least because the context of ‘discovery’ is never a one-off experiment.

Note that, in all cases, having made the initial unexpected observation – either from unstructured exploratory research, or in the course of investigating something else – the researchers went on to shore up the findings with further, hypothesis-driven experiments. What they did not do is to report just the initial observation, embellished with statistics, and then move on, as if the presence of a low p-value guaranteed the truth of the result.

(It’s hard not to read into these comments a criticism of some academic journals which seem happy to publish single experiments reporting surprising findings.)

Bishop’s list contains 3 findings from electrophysiology (recording brain cell activity directly with electrodes), which I think is notable. In these cases neural recording acts in the place of a microscope, allowing fairly direct observation of the system the scientist is investigating at a level of detail hitherto unavailable. It isn’t surprising to me that given a new tool of observation, the prepared mind of the scientists will make serendipitous discoveries. The catch is whether, for the rest of psychology, such observational tools exist. Many psychologists use their intuition to decide where to look, and experiments to test whether their intuition is correct. The important serendipitous discoveries from electrophysiology suggest that measures which are new ways of observing, rather than merely tests of ideas, must also be important for psychological discoveries. Do such observational measures exist?

Good tests make children fail – here’s why

Many parents and teachers are critical of the Standardised Assessment Tests (SATs) that have recently been taken by primary school children. One common complaint is that they are too hard. Teachers at my son’s school sent children home with example questions to quiz their parents on, hoping to show that getting full marks is next to impossible.

Invariably, when parents try out these tests, they focus on the most difficult or confusing items. Some parents and teachers can be heard complaining on social media that if they get questions wrong, surely the tests are too hard for ten-year-olds.

But how hard should tests for children be?

As a psychologist, I know we have some well-developed principles that can help us address the question. If we look at the SATs as measures of some kind of underlying ability, then we can turn to one of the oldest branches of psychology – “psychometrics” – for some guidance.

Getting it just right

A good test shouldn’t be too hard. If most people get most questions wrong, then you have what is called a “floor effect”. The result is that you can’t tell any difference in ability between the people taking the test.

If we started the school sports day high jump with the bar at two metres high (close to the world record), then we’d finish sports day with everybody getting the same – zero successful jumps – and no information about how good anyone is at the high jump.

But at the same time, a good test shouldn’t be too easy. If most people get everything right, then the effect is, as you might expected, called a “ceiling effect”. If everybody gets everything right then again we don’t get any information from the test.

The key idea is that tests must discriminate. In psychometric terms, the value of a test is about the match between the thing it is supposed to measure and the difficulty of the items on the test. If I wanted to gauge maths ability in six-year-olds and I gave them all an A-Level paper, we can presume that nearly everyone would score zero. Although the A-Level paper might be a good test, it is completely uninformative if it is badly matched to the ability of the people taking the test.

Here’s the rub: for a test to be sensitive to differences in ability, it must contain items which people get wrong. Actually, there’s a precise answer to the proportion that you should get wrong – in the most sensitive test it should be half of the items. Questions which you are 50% likely to get right are the ones which are most informative.

How we feel about measuring and labelling children according to their skill at taking these tests is a big issue, but it is important that we recognise that this is what tests do. A well designed test will make all children get some items wrong – it is inherent in their design. It is up to us how we conceptualise that: whether tests are an unnecessary distraction from true education, or a necessary challenge we all need to be exposed to.

Better tests?

If you adopt this psychometric perspective, it becomes clear that the tests we use are an inefficient way of measuring any individual child’s particular ability to do the test. Most children will be asked a bunch of questions which are too easy for them, before they get to the informative ones which are at the edge of their ability. Then they will go on to attempt a bunch of questions which are far too hard. And pity the people for who the test is poorly matched to their ability and consists mostly of questions they’ll get wrong – which is both uninformative in psychometric terms, and dispiriting emotionally.

A hundred years ago, when we began our modern fixation with testing and measuring, it was hard to avoid the waste where many uninformative and potentially depressing questions were asked. This was simply because all children had to take the same exam paper.

Nowadays, however, examiners can administer tests via computer, and algorithmically identify the most informative questions for each child’s ability – making the tests shorter, more accurate, and less focused on the experience of failure. You could throw in enough easy questions that no child would ever have the experience of getting most of the questions wrong. But still there’s no getting around the fact that an informative test has to contain questions most people sitting it will get wrong.

Even a good test can measure an educationally irrelevant ability (such as merely the ability to do the test, or memorise abstract grammar rules), or be used in ways that harm children. But having difficult items isn’t a problem with the SATs, it’s a problem with all tests.

The Conversation

This article was originally published on The Conversation. Read the original article.

The search for the terrorist ‘type’

BBC World Service has an excellent radio documentary on the history and practice of terrorist profiling.

Unlike many pieces on the psychology of terrorism, which tend to take a Hollywood view of the problem, it’s an insightful, critical and genuinely enlightening piece on the false promises and possibilities of applied psychology in the service of stopping terrorists.

Crucially, it looks at how the practice developed over time and how it’s been affected by the ‘war on terror’.

For decades researchers, academics and psychologists have wanted to know what kind of person becomes a terrorist. If there are pre-existing traits which make someone more likely to kill for their beliefs – well, that would be worth knowing… It’s a story which begins decades ago. But, with the threat from killers acting for so-called Islamic State, finding an answer has never felt more pressing.

Recommended.
 
Link to programme webpage, streaming and mp3.

A brief hallucinatory twilight

CC Licensed Photo by Flickr user Risto Kuulasmaa. Click for source.I’ve got an article in The Atlantic on the hypnagogic state – the brief hallucinatory period between wakefulness and sleep – and how it is being increasingly used as a tool to make sense of consciousness.

There is a brief time, between waking and sleep, when reality begins to warp. Rigid conscious thought starts to dissolve into the gently lapping waves of early stage dreaming and the world becomes a little more hallucinatory, your thoughts a little more untethered. Known as the hypnagogic state, it has received only erratic attention from researchers over the years, but a recent series of studies have renewed interest in this twilight period, with the hope it can reveal something fundamental about consciousness itself.

The hypnagogic state has been better dealt with by artists and writers over the years – Colderidge’s poem Kubla Khan apparently emerged out of hypnagogic reverie – albeit fuelled by opium

It has received only occasional attention from scientists, however. More recently, a spate of studies has come out showing some genuine mainstream interest in understanding hypnagogia as an interesting source of information about how consciousness is deconstructed as we enter sleep.

 

Link to article in The Atlantic on the hypnagogic state.

Genetics is rarely just about genes

If you want a crystal clear introduction to the role genetics can play in human nature, you can’t do much better than an article in The Guardian’s Sifting the Evidence blog by epidemiologist Marcus Munafo.

It’s been giving a slightly distracting title – but ignore that – and just read the main text.

Are we shaped more by our genes or our environment – the age-old question of nature and nurture? This is really a false dichotomy; few, if any, scientists working in the area of human behaviour would adhere to either an extreme nature or extreme nurture position. But what do we mean when we say that our behaviours are influenced by genetic factors? And how do we know?

It will be one of the most useful 20 minutes you’ll spend this week.
 

Link to excellent introduction to genetics and human behaviour.

3 salvoes in the reproducibility crisis

cannonThe reproducibility crisis in Psychology rumbles on. For the uninitiated, this is the general brouhaha we’re having over how reliable published psychological research is. I wrote a piece on this in 2013, which now sounds a little complacent, and unnecessarily focussed on just one area of psychology, given the extent of the problems since uncovered in the way research is manufactured (or maybe not, see below). Anyway, in the last week or so there have been three interesting developments

Despair

Michael Inzlicht blogged his ruminations on the state of the field of social psychology, and they’re not rosy : “We erred, and we erred badly“, he writes. It is a profound testament to the depth of the current concerns about the reliability of psychology when such a senior scientist begins to doubt the reality of some of the phenomenon upon which he has built his career investigating.

As someone who has been doing research for nearly twenty years, I now can’t help but wonder if the topics I chose to study are in fact real and robust. Have I been chasing puffs of smoke for all these years?

Don’t panic!

But not everyone is worried. A team of Harvard A-listers, including Timothy Wilson and Daniel Gilbert, have released press release announcing a commentary on the “Reproducibility Project: Psychology”. This was an attempt to estimate the reliability of a large sample of phenomena from the psychology literature (Short introduction in Nature here). The paper from this project was picked as one of the most important of 2015 by the journal Science.

There project is a huge effort, which is open to multiple interpretations. The Harvard team’s press release is headlined “No evidence of a replicability crisis in psychological science” and claimed “reproducibility of psychological science is indistinguishable from 100%”, as well as calling from the project to put effort into repairing the damage done to the reputation of psychological research. I’d link to the press release, but it looks like between me learning of it yesterday and coming to write about it today this material has been pulled from the internet. The commentary announced was due to be released on March the 4th, so we wait with baited breath for the good news about why we don’t need to worry about the reliability of psychology research. Come on boys, we need some good news.

UPDATE 3rd March: The website is back! No Evidence for a Replicability Crisis in Psychological Science. Commentary here, and response

…But whatever you do, optimally weight evidence

Speaking of the Reproducibility Project, Alexander Etz produced a great Bayesian reanalysis of the data from that project (possible because it is all open access, via the Open Science Framework). This take on the project is a great example of how open science allows people to more easily build on your results, as well as being a vital complement to the original report – not least because it stops you naively accepting any simple statistical report of the what the reproducibility project ‘means’ (e.g. “30% of studies do not replicate” etc). Etz and Joachim Vandekerckhove have now upgraded the analysis to a paper, which is available (open access, natch) in PLoS One : “A Bayesian Perspective on the Reproducibility Project: Psychology“. And their interpretation of the reliability of psychology, as informed by the reproducibility project?

Overall, 75% of studies gave qualitatively similar results in terms of the amount of evidence provided. However, the evidence was often weak …The majority of the studies (64%) did not provide strong evidence for either the null or the alternative hypothesis in either the original or the replication…We conclude that the apparent failure of the Reproducibility Project to replicate many target effects can be adequately explained by overestimation of effect sizes (or overestimation of evidence against the null hypothesis) due to small sample sizes and publication bias in the psychological literature