Should psychiatry abandon "natural science" methods as critical psychiatry says we should?

Should psychiatry abandon “natural science” based methods?

Introduction

Critical psychiatrists claim that natural science methods are of little use in studying humans and their problems that form the subject matter of mental health  due to their ignoring important factors such as intentionality, meaning and being embodied in social contexts and that social science methods such as hermeneutics  are preferred (Middleton & Moncrieff, 2019).

I will argue that natural science methods include descriptions such as observation of outcomes of interest to provide the information on causes, complications and treatment responses needed for medical practice. Natural science techniques even in unquestioned natural sciences such as physics may also struggle to discover universal laws because of the effect of multiple interactions, yet we still use them to explain relationships between observable entities hence this is no reason to disbar them in mental health. They can be used to establish causations of organic mental disorders.  Even for functional mental health problems where natural science methods are not used to explain causation these problems are negatively defined using natural science methods. Finally, it may be possible to use natural science methods to study relationships between social contexts and mental health problems. Psychiatry should still use natural science methods.

What is the attitude of critical psychiatry to the use of natural science techniques?

An article describing critical psychiatry (Middleton & Moncrieff, 2019) stated one key attitude was the applicability of scientific methodology in psychiatry. This is quoted in full to avoid any summarising on my part being misleading about their position.

“Medical knowledge is identified with the scientific approach that was developed to study the natural world; systematically investigating assumed-to-be immutable truths by measurement and manipulation of particular elements in a controlled environment. The application of this form of knowledge-seeking to the world of human affairs is referred to as ‘positivism’, an approach that has been criticised for oversimplifying human affairs. Earlier scholars distinguished between Geisteswissenschaften, human or moral sciences, and Naturwissenschaften, natural sciences. The distinction remains a core feature of social science, where it is argued that the study of human beings is irreducibly different from the study of the natural world. Human behaviour is intentional, interactive and inextricable from its social setting. It has meaning, rather than causes, that can only be discerned by reference to its context.

Therefore, if mental disorders are to be understood as human reactions rather than as physical diseases, a positivist perspective cannot provide adequate or comprehensive knowledge. Different approaches are needed that can study social phenomena appropriately.” (Middleton & Moncrieff, 2019: 49)

Alternative social science approaches such as hermeneutics and social constructivism are suggested as alternatives (Middleton & Moncrieff, 2019: 49)

The article summary stated:

“Critical psychiatry does not reject science, but questions the applicability of positivist research paradigms to the study of complex human responses, suggesting that other epistemologies may often be more enlightening.” (p. 53)

An article on the ‘Critical Psychiatry Network’ also described the views of critical psychiatry (Double, 2019) including their view on the role of “natural science” methods.

“However, critical psychiatry’s challenge to reductionism and positivism, including mechanistic psychological approaches, does create a framework which focuses on the person and has ethical, therapeutic and political implications for clinical practice. It also has consequences for psychiatric research, which has become too focused on speculative neurobiological notions” (p.62)

These articles particularly the former promulgate the view that “natural science” methods  

“systematically investigating assumed-to-be immutable truths by measurement and manipulation of particular elements in a controlled environment” (Middleton & Moncrieff, 2019 p.49).

are not suitable for “the study of human beings” (Middleton & Moncrieff, 2019 p.49).   

Critical psychiatry regards the subject of psychiatric research and clinical practice – what problems people present with and are seen by psychiatrists– as “human reactions” or “meaningful responses” (Middleton & Moncrieff, 2019 p.49). The article by Double places a limit on what is referred to is mental health problems not clearly linked to somatic disease such as hypothyroid induced depression or Alzheimer’s disease

“the essential position of critical psychiatry is that functional mental illness should not be reduced to brain disease...Functional mental illness is a personal experience that does not have an underlying brain pathology. No definite biomarkers have been linked to functional mental illness” (Double, 2019 p. 62).

 “Natural science” techniques are described here as controlling for potentially confounding variables whilst altering the experimental variable with results being used to produce “immutable laws”. For the problems that come to psychiatrists this method is regarded as not being able to provide “adequate or comprehensive knowledge” because they are “human reactions” and as such are driven by intentions and are meaningful in response to multiple contexts. Thus, controlling for these contextual factors – regarded as confounding by the “natural sciences” – in order to examine the effects of a single experimental factor (even if it is a social factor such as class) cannot explain why the behaviour happened. There is also a view that meaningful intentional behaviour belongs to the “space of reasons” and may not conform to the “realm of laws” (McDowell, 1994) and hence natural science methods cannot thus provide explanations.

What kinds of information do psychiatrists need for clinical practice?

To address the question of which type of scientific methodology is best for psychiatry we need to know why they need science.

“The link between psychiatry and medicine confers legitimacy on psychiatry as a professional enterprise because its practitioners are seen to hold and exploit expert medical knowledge” (Middleton & Moncrieff, 2019. P. 48-49).

Science is thus used to gain information – for critical psychiatry this is to cement psychiatry’s professional status. Another reason, which may still apply with the previous reason, is that doctor’s professional role to advise on, coordinate, or deliver interventions for health improvement should be based on the best possible evidence gained from science (Shah & Mountain, 2007).

The type of information doctors need for clinical practice can be ascertained by descriptions of ‘clinical utility’ that is stated to come from diagnostic constructs. Diagnostic constructs are used as containers of information – the question of their suitability as carriers of information in psychiatry is not relevant here but given the centrality of making a diagnosis is to medical practice, the purported information attached to a diagnosis is clearly thought to be essential.

Examples of the type of information include

“nontrivial information about prognosis and likely treatment outcomes, and testable propositions about biological and social correlates” (Kendell & Jablensky,2003. P.9)

A more exhaustive list of useful information is listed below

“1.  Conceptualizing diagnostic entities

2.  Communicating   clinical   information   to   practitioners, patients and their families, and health care systems administrators

3.  Using diagnostic categories and criteria sets in clinical practice (including for diagnostic interviewing and differential diagnosis)

4.  Choosing effective interventions to improve clinical outcomes

5.  Predicting future clinical management needs” (First et al, 2004. P.947)

In this list points 2 and 3 relate more to the use of diagnosis in other functions so will be ignored.

Therefore, the types of information that doctors including psychiatrists require include information on likely outcomes (prognosis), the effectiveness of various interventions for this type of problem, what problems may occur in future (complications) and what possible causative mechanisms may be involved (aetiology). The other important thing to note is this type of information is in the form of a range of probabilities not binary information. Even with conditions with almost certain mortality, it is important to know the likely range of possible survival time.

What is the best way to acquire this information?

Doctors can use the patient’s history to provide some of this information in an idiographic fashion. If they have had episodes of low mood in the past in response to interpersonal stressors then you can predict that an upcoming family wedding mixing with hated in-laws may trigger low mood; if they found that a certain type of medication helpful then it may be helpful in the future. If patient had an abscess and they were allergic to penicillin in the past then even If the microscopy culture and sensitivity showed penicillin was the most effective antibiotic you would not prescribe penicillin. This relies on the patient’s past predicting the future – so long as the patient has all the relevant experience.

Often though this information is not available – the patient may not have experienced this type of health problem before to provide guidance on treatments or prognosis, the patient may not be able to recall accurately the information, the patient may be at risk of a complication or problem they have never experienced so cannot be guide in themselves as to the risk of this problem (they may have never had a heart attack but the doctor may be interested in their risk of a heart attack or whether vaccination to prevent a disease is advisable) or they may not have tried a potential treatment so cannot tell you whether it will be effective or if they experienced any side effects.

The commonest way in current medical practice to get this useful information is research on people whose problems resemble the problems of the patient in the clinic in front of them in some way (Kendell in Shepherd & Zangwill (1983): 191-198). This type of research may be simple observation by a clinician that is recorded or remembered in some fashion all the way up to multi-million pound projects involving many researchers. The information gained from this research can then be used to give some idea of probabilistic information of the types described in the previous section.

The natural scientific method is described as a method of investigation to ascertain laws (Middleton & Moncrieff, 2019) but scientific methods are used to describe phenomena as well as explain what is described using laws (Hempel in Sadler et al, 1994: 317-18). Descriptive goals can be achieved by observation and use of standardised terminology to facilitate communication, replication and application by others such as doctors in their clinical practice. For medical practice, important information can be gained by observation of participants with some commonality of their problems - at repeated intervals if necessary – of classified events to gain knowledge on prognosis/ complications of mental health problems, effectiveness and side-effects from treatment.

For this nomothetic approach from research to be useful it relies on several possible mechanisms. One is that the similarities between research participants and the patient in the clinic increases the chances of making successful inferences - the probabilities of recovery or rates of response to treatment -as they have an increased chance of sharing some fundamental quality even if it is unknown. Practical kinds that perhaps share external features such as similarities in symptoms rather than common mechanisms or causes have a greater degree of uncertainty making inferences from research to the clinic. Another possibility is that even if the mechanisms are unknown and the participants are heterogenous there maybe some common elements of mechanisms (mechanistic property clusters) allowing greater degrees of certainty. For natural kinds with common mechanisms and/or causes the certainty is greater still (Kendler et al, 2011). The knowledge gained from research has a degree of uncertainty, greatest when relying on “practical kinds” but also influenced by the effect of multiple contextual factors (such as participants in research differing markedly from patients seen in clinical practise) but information even with great degrees of uncertainty is still better than no information at all so long as this degree of uncertainty is taken into account in decision-making.

If general laws are demonstrated that can offer explanation of observed descriptive data – such as increase in neurochemical x leads to increase in symptom y then this can allow a greater degree of explanation and extrapolation from research participants to the patient in the clinic. With this higher degree of explanation comes increased predictive ability – it can lead to increased understanding and explanation of the patient’s situation; an increased knowledge of the mechanisms can allow increased predictive ability for complications and prognosis and more rational choices in treatment and development of more effective treatments in future.

It is important to recognise that there are certain limitations to using natural science methods in mental health. The information gained even if only descriptive uses classifications varying from a “black box” type where we have little explanation to types with a great degree of explanation. There is always a degree of uncertainty but even in the most uncertain cases, information with high degrees of uncertainty is better than no information at all so long as one is aware of the degrees of uncertainty (see evidence pyramid and subsequent strengths of recommendation).

Do natural science techniques have limits for explaining and establishing causation in mental health problems?

Middleton and Moncrieff state that human beings cannot be studied by natural science but later specifies “behaviour” and “human reactions”. It makes the case that behaviour, thoughts, emotions and so forth cannot be studied in a natural science way because this ignores context, personal history, meaningfulness that do not apply to the subjects of natural sciences such as subatomic particles and animals.

Middleton and Moncrieff describe natural science’s “immutable truths” derived from “controlled” “manipulation” of “particular elements”. It is true that scientific practice often tries to generate observations from experiments aiming to minimise the effects of confounding variables to clarify the role of the experimental variable. Are these experiments in natural sciences such as physics or chemistry producing “immutable truths”? No, they provide results that operate under certain conditions. For example, determining the state of water as a liquid depends on certain conditions of temperature and external pressure. Even what we may regard as relatively stable phenomenon in physics such as the passage of time are changed by near-relativistic speeds and the laws of physics were different at the time of the big bang and continued to evolve even during tiny fractions of a second afterwards.

We cannot expect “immutable truths” very often, if at all, in the hard sciences. What we get is contextual-influenced observations. Hacking suggests that whilst proving that theories (these explanatory underpinning “laws”) are real may be an ultimate goal of scientists but in practice most scientific work is concerned with manipulations of observable entities and the relationships between them (Hacking in Boyd et al, 1999: 247-260). So in psychiatry we natural scientific methods may be used to observe interactions between say giving an antidepressant and effects on depression without necessarily proving an underpinning law predicting the entire effects of the antidepressant on speech and behaviour (it might demonstrate a relationship between a reduced tendency to have less negative thoughts but not the exact content of the negative thought).

In terms of explanations of human behaviour and speech there is always going to an effect of culture, history and environment. Delusions in the 19th Century were often religious due to the importance of religion in culture; nowadays people often have delusions around technology such as television or the internet which were not around in the 19^th Century. Now if we posit a biological causation for delusions then a purely biological model cannot explain this variation – it may say delusions around available technology have a biological basis but not why the patient talks about being controlled by wifi now and emissions from natural gas used in lighting in the 19^th Century - that is due to historical contingent factors as to what technology is available.

Psychiatric symptoms and signs have been described as ‘hybrid objects’ (Markova and Berrios in Zachar et al, 2015) where this model leaves aside the question of causation. The term ‘objects’ describes constructs that are used to depict or explain aspects of the world. The generation of psychiatric symptoms as signs are said to be ‘hybrid’ because they involve combinations of biological and semantic elements—a biological element/kernel is contained within two layers of configurating envelopes.

The cause of the biological element is not depicted in this model. The biological element refers to the brain activity associated with the symptom or sign. This might be, for example, nervous activity that is a corollary of the patient’s thoughts.

C4.P4

 The two configurating envelopes describe the semantic and contextual elements that act to configure and modify the interpretation and expression of the biological element successively. The first envelope involves individual and sociocultural forces (such as personality traits and culture) whilst the second envelope consists of interactional forces (e.g. between doctor and patient or within a broader social context) (Markova and Berrios in Zachar et al, 2015)).The second type of  configurating envelope describes interactions including that between the patient discussing their experiences with somebody else.

Thus, any explanation of a patient’s behaviour or speech will necessarily include contextual social and interpersonal factors. This means any explanation from laws derived natural scientific methods will also need to explain these contextual and interpersonal factors in order to claim a full explanation of the mental health problems expressed in behaviour and speech.  For laws derived from natural science methods to be able to explain the entire reasons for behaviour they have to be able to explain these contextual social and interpersonal/ interactional factors.

Even in what seem paradigmatic natural sciences such as physics it has been argued that laws derived from the uncontested use of natural science methods fail to explain as much as people think. They often have certain assumptions such as “all things being equal” which in practice is hard to achieve to control for all contextual factors absolutely even in experiments let alone in naturally occurring situations (Cartwright, 1983). Cartwright puts forward the argument that natural science methods even in physics only allow us to make predictions about relationships between observable events rather than hidden laws. Interestingly, Cartwright makes a direct comparison between the behaviour of particles and people.

“I imagine that natural objects are much like people in societies. Their behaviour is constrained by some specific laws and by a handful of general principles but is not determined in detail, not even statistically. What happens on most occasions is dictated by no law at all.” (Cartwright, 1983: 49).

 Even in physics it is also hard to establish causality.

“All the counter examples I know to the claim that causes increase the probability of their effects work in this same way. In all cases the cause fails to increase the probability of its effects for the same reason: in the situation described the cause is correlated with some other causal factor which dominates in its effects. This suggests that the condition as stated is too simple. A cause must increase the probability of its effects; but only in situations where such correlations are absent” (Cartwright 1983: 25).

Given these problems with uncontested use of natural science methods in paradigmatic natural sciences such as physics in being able to establish laws that can explain everything and to establish causation, it would be reasonable to infer that for the experiences/behaviours patients have that are disvalued that result in them receiving psychiatric care may not be able to have laws discovered that predict and explain them totally or establish causation using natural science methods. There may be at least a gap where different types of methods may be useful, a “space of reasons” perhaps where the social science methods advocated by Moncrieff and Middleton may be advantageous.

Can we really do without natural science methods at all in psychiatry?

There may be certain situations or certain areas when natural science methods may fail to explain fully the speech, thoughts or behaviour of people with mental health problems. It is possible that in all patients the contextual broader sociocultural factors and interpersonal factors that affect speech/ thought/ behaviour (as described by Markova and Berrios in Zachar et al, 2015) are the “space of reasons” requiring different methods than the natural science methods. On the other hand, it is well recognised there are cases when mental health problems are at least in part “the psychological consequences of cerebral disorder” such as general paralysis of the insane, hypothyroid induced depression or the dementias (Lishman, 1997). It is untenable that in cases of what would be regarded as ‘organic mental disorders’ that natural science techniques would be of no use. As Berrios & Markova suggests yes the exact content of speech and behaviour is affected by broader contextual factors but surely the presence of neurosyphilis is germane to the patient talking of their fantastical schemes or an underactive thyroid in a patient with depressed mood and paranoid psychosis? Natural science surely has a role to play when clear-cut biological factors seem to be strongly related to the mental health problems – not only for judging aetiology but also prognosis and treatment even if they cannot fully explain all the details of someone’s speech or behaviour.

Double suggests that ‘critical psychiatry’ is only referring to ‘functional’ mental health problems. But what is a ‘functional’ mental health problem? It is a negatively defined state – one where there is an absence of a biological cause that has been demonstrated in the research to cause the defined problem. How do know what biological causes cause these problems? By using natural scientific methods to demonstrate an absence of a demonstrated biological cause. So even if we adopt the position of only using the social science methods suggested for functional mental health problems these need to be defined by using natural science methods to confirm they are functional mental health problems. Furthermore, one cannot state that with further advances in scientific techniques we will not identify in future biological causes for some cases of mental health problems that are not apparent now. We already have an example in antiNMDA encephalitis that in the time of Szasz he would describe as a ‘problem in living’ as the ability to detect the relevant antibodies was unavailable.

It may be possible to use natural science methods to study the effects of social contextual and interpersonal factors on a variety of outcomes such as the relationship of employment to ethnic minority status. In line with Hacking’s view, Brown and Harris used a standardised interview with reasonable reliability – the Life Events and Difficulties Schedule – to measure the relationships between described observable entities:  social contexts, life events and interpersonal difficulties and the risk of developing depression in women (Brown & Harris, 1978). This demonstrated that social contexts and interpersonal factors (three or more life events, lack of social confidants) and their effects on depression (an increased risk in women) could be measured and a relationship demonstrated even though the full meanings and a satisfactorily predictive law of all resultant phenomena were not demonstrated.

Conclusion

Critical psychiatry states that natural science methods should be replaced by social science methods such as hermeneutics because such techniques cannot explain the speech and behaviour of people with mental health problems as this requires understanding of social contexts and interpersonal interactions. The critical psychiatry view ignores that natural science has descriptive and explanatory aims. Descriptive methods can be used to gain information on information that is important to medical practice including psychiatry such as probabilistic information on prognosis, complications, and treatment responses.

Natural science methods can struggle to establish laws that fully explain behaviours of bodies and particles in physics due to the difficulty of fully accounting for contexts and this may apply to establishing laws that can fully explain speech and behaviour due to the effect of social contexts.  Natural science methods can have some explanatory value in ‘organic’ mental disorders. Even if we accept that natural science methods cannot be used to explain speech and behaviour at all  in ‘functional’ mental health problems then we still need natural science methods to negatively define these ‘functional’ mental health problems and in the future scientific advances may allow us to identify biological cases of what seemed to ‘functional’ mental health problems  for which natural scientific methods could be applied to. Natural science methods can still be used to establish relationships between reliably described and observed contextual and interpersonal factors even if the full meanings cannot be described or explanatory laws established.

In conclusion, natural science methods should not be abandoned by psychiatry.

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Fine NOA

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Hacking

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