The Evolutionary Mismatch Behind ADHD, Anxiety and Poor Sleep

Isn’t it  a paradox that while our society has become safer, wealthier, more comfortable, we are seemingly less adapted to it?  I mean, why do some of the innate capacities essential to human flourishing, such as attention, emotional balance, restorative sleep, appear increasingly fragile in modern society?

Ciao. I’m Elisabetta Burchi, physician, clinical psychiatrist, and the host of the Renaissance Doctor.

This podcast exists to explore an ambitious question: what does it mean to fully flourish as human beings in the 21st century?Today, I’m going to talk about mental health and environment, about how certain mental health issues do not derive by any intrinsic malfunctioning, but are, the expected expressions of regulatory systems finding to operate in an environment which they didn’t evolve for.

The idea came from a recent talk I gave at a longevity conference. calm the adhd, I was, in fact, asked to prepare a talk around the following title:  “calm the chaos: adhd, anxiety and insomnia”.

Honestly, my first reaction to the title was irritation., I always feel the duty to be comprehensive, in front of tasks, and it was clear that I could not in a few minutes cover such a landscape that, by the way, put together apples with oranges.

Because ADHD is a syndrome, anxiety is an emotion, and insomnia is a symptom. 

But a second excited thought replaced that first annoyed one quickly.  That title, which might have probably been proposed by somebody that didn’t know much about the topic, could have become an opportunity to address what I consider to be one of the main shortcomings of traditional clinical what I consider to be one of the main shortcomings of traditional clinical psychiatry and showcase instead a more recent, innovative way to look at at mental health.

If you have listened to my first episode, you might have perceived that I’m very inclined to talk about methods, definitions and frameworks. ILet’s then start from two key assumptions that I’m going to build my narrative on.

First, I will assume a dimensional framework to look at mental health, which means that I would not use the traditional medical categorical lens, which means that I would not use the traditional medical categorical lens, which identifies conditions based only on the presence or absence of specific symptoms, but I will consider adhd, anxiety and insomnia as multidimensional entities placed on a spectrum. Second, I will also assume an evolutionary angle, because when we look Second, I will also assume an evolutionary angle, because, when we look at living systems, it is always very informative to inquire about the adaptive capacity of certain functions in relation to the environment.

Only two assumptions. As the parsimony principle commands, the explanation with fewer assumptions is generally the best one available.

I hope I will prove my thesis. 

Since I am not Agatha Christie, let me anticipate who the murderer is. I want to show that adhd, anxiety and insomnia might not be entirely separate conditions, but different expected manifestations of the same regulatory system under certain environmental conditions for which that system didn’t evolve for in the first place.

My core thesis is that dysregulation of that system, -, which is the stress system –  can explain comorbidity across different conditions and across levels of analysis.

Let’s start with epidemiology –  So the occurrence of diseases in the population.

Over the last decade, diagnosis of subclinical or full blown adhd, anxiety disorders and sleep disorders have all been increasing.

Current understanding often considers inattention, anxiety and insomnia and the relative syndromes as separate problems and consequently address them with different treatments.

However, the rising impact and even co-occurrence of this triad suggest to me that there might be a common denominator behind this phenomenon.

And since human beings are open systems and human physiology changes in geological areas, it is possible that what is changing might not be biology, but the interaction with the external environment.

Modern environment indeed exposes us and our nervous system to conditions unprecedented in human history.  Constant informational input, t digital attention capture, continuous social comparison and evaluation,

blurred boundaries between work and rest. These conditions are very different from the ones we encountered in our ancestral environment, rather characterised by physical threats, natural day and night cycles and scarcity of resources.

I think that understanding how environmental conditions interact with our neurobiology can be critical for better understanding our own mental health. If we could show that some of the core clinical characteristics  of these syndromes are related epiphenomena, manifestations of the same strained underlying regulatory process within a specific environment, we might also find new therapeutic targets to take care of our mental health.

Let me then expand on this. Let me show what adhd, anxiety and insomnia have in common. Let me show how modern environments underpin rises in their prevalence and why restoring autonomic nervous system regulation might be the missing lever.

Let’s delve first on the conditions themselves and let me show how we can usefully apply a dimensional perspective to uncover a common denominator.

The standard approach in psychiatry as in medicine as a whole, is to address patients’ complaints through the mediation of the diagnostic process.

Psychiatric illnesses, properly termed “disorders” in psychiatry, are still primarily defined on the basis of symptom clustering.

Importantly, as of now, none of the disorders described solely on the basis of symptoms in the DSM 5, which is the diagnostic manual used by psychiatrists worldwide, has any validated biomarker.

That means that anything that you can singularly measure will lead you to a specific diagnosis in psychiatry. 

This fact suggests two things: first that psychiatric conditions are complex and not fully describable by biological footprints alone; and second, that psychiatric disorders as currently defined by symptom clustering might not point to discrete biological entities. 

When it comes to behaviours, thoughts and emotions, symptom clustering may then be an insufficient and sometimes misleading way for making distinct diagnoses and selecting treatments. 

Basically, relying on a single descriptive level – the symptomatic one, for instance -might be inadequate to guide  both understanding and treatment of certain conditions. 

Well, while clinicians traditionally work with categorical diagnosis – diagnosis based on the presence or absence of certain number of symptoms –  in neuroscience research we are increasingly n resorting to the dimensional framework, examining mental phenomenon resorting to this dimensional framework, examining mental phenomena in a continuum and across multiple levels, the genetic one, the in a continuum and across multiple levels: the genetic one, the neural circuit one, the physiological one, the behavioural one, up to the subjective one.

This dimensional multi-layer framework allows us to see converging mechanisms across conditions and redefine them in the diagnosis and also in the treatment. 

Let’s go back to our triad.

Although ADHD, anxiety disorders and insomnia can be distinct clinical syndromes, they often show some overlapping physiological patterns. There is one main shared physiological feature: an increased stress sensitivity with heightened sympathetic activation and stress sensitivity – with heightened sympathetic activation and difficulty downregulating arousal – and an overall reduced physiological flexibility.

I already mentioned the concept of flexibility in the first episode, while talking about an inherent characteristic of health. The concept of physiological flexibility is closely tied to the concept of  allostasis, which in the 80s was used to complement the concept of homeostasis.

Most people are familiar with this concept – homeostasis –  the body’s tendency to maintain stability.

But living systems do something even more sophisticated. They constantly anticipate change and adapt to it. While, homeostasis, which means “same state”, refers to the capability of the organism to maintain its internal conditions relatively stable, mainly through feedback loops, allostasis means “different state” and refers to the process by which the body achieves stability through predictive processes and dynamic adaptation.

And the stress response is the main coordinated set of actions that the body puts in place to maintain that dynamic stability. The stress response is physiologically implemented by the so called Extended autonomic system, which integrates the sympathetic and parasympathetic nervous autonomic system with neuroendocrine axes such as the HPA axis and neuroimmune pathways.

Individuals who can appropriately escalate and then down regulate these systems in response to stressors demonstrate resilience, whereas those with inflexible or dysregulated responses are at risk for allostatic overload – the cumulative wear-and-tear from chronic and maladaptive stress which predisposes to mental and physical morbidity.

Flexibility implies that an individual can appropriately engage and efficiently terminate stress responses by titrating the magnitude and duration of physiological activation to match the actual challenge.

And the autonomic nervous system is the primary effector of moment-to-moment physiological regulation across the multiple systems  across the cardiovascular, the metabolic, the immune and the visceral functions.

A Autonomic flexibility  – the capacity to shift dynamically between sympathetic (fight or flight) or parasympathetic (rest and digest) states is a key determinant of adaptive stress responses. Think about heart rate variability. This is a widely used non-invasive index of autonomic flexibility. Higher HRV reflects greater parasympathetic or vagal tone and the capacity for rapid, context-appropriate autonomic adjustments and has been associated with resilience, effective emotional regulation, and with better health outcomes.

On the contrary, reduced HRV is linked to autonomic rigidity, maladaptive stress responses and increased risk of cardiovascular and psychiatric disorders.

To come back to our three  – adhd, anxiety disorders and insomnia disorders –   as we said, they share a common physiological pattern: chronic hyper arousal and impaired downregulation.

These features do not explain every aspect of these conditions. TFor example, ADHD also involves reward processing and executive function dynamics.. Anxiety involves threat prediction and uncertainty processing.

Insomnia involves complex sleep  wave  regulation mechanisms. However, stress system dysregulation may contribute to certain key aspects of those syndromes, particularly inattention, emotional reactivity and sleep regulation.

Let’s now shift to the second angle of this discussion- the evolutionary one – which allows us to state the importance of considering our mind and body as a complex and open system.

Modern environment is totally different from the ancestral one where our stress response and extended autonomic system was selected because serving survival.

Our ancestral environment was characterised by acute intermittent O physical threats, scarce rewards and natural day night rhythms.

The human nervous system evolved selected by pressures exercised by that environment and  becoming good at i) flexible attention which serves fast life threat detection, ii) high novelty seeking, which serves survival in a place characterised by scarcity and iii) rapid stress mobilisation which again serves survival by fast fight-or-flight response.

Here we clearly see the evolutionary mismatch: while our nervous system capabilities have remained the same, modern environments, while much safer from a life-threatening perspective, and generous in terms of basic needs satisfaction capability expose us to unprecedented 24 hour engagement.

While certain traits were highly adapted for survival in the ancestral environment, they gave rise to what we call now symptoms in the current environment: persistent arousal, fragmented focus, effort avoidance, disrupted sleep, incapability to learn, reduced physiological recovery.

I think the paradoxes, behind apparent nonsense, have the power to show deeper logic. And here we have multiple paradoxes.

A physiological one: we are cognitively and emotionally overstimulated, but physiologically under-recovered and less capable of performing. And this paradox, mirrors another paradox, a societal one, the paradox of infodemics, which highlights how overabundance of information might not lead to better decisions.

But at a more attentive look, we can see a vicious loop which explains the paradox. When cognitive and emotional load is high, the brain avoids forceful tasks and favours info that are belief-consistent.

Avoidance decreases performance which increases anxiety. Anxiety increases arousal.

Arousal fragments attention, fragmented attention and overfitting further impairs performance which further increases anxiety.

Modern environments amplify stress activation while preventing recovery.

Our symptoms then are predictable consequences of our autonomic nervous system which is naturally unfitted to the modern environment. 

If this thesis has some merit, it has implications both for medicine and for the whole society.

As a health professional I believe that people’s health should not be regarded solely as the responsibility of healthcare systems. If modern environments systematically amplify stress activation while preventing recovery, then part of the solution cannot lie exclusively within medicine nor the individual.

It requires rethinking the environments in which we live. 

That is ultimately a political, cultural and societal challenge. One that may require a joint coordinated effort far beyond the healthcare systems alone.

At the same time, this framework also has important clinical implications. While most existing treatments for adhd, anxiety disorders, target neurotransmitters,cognitive patterns or behavioural strategies, this perspective highlights an additional therapeutic target: physiological regulation capacity itself.

Strengthening stress-response flexibility and autonomic regulation may not replace existing treatments, but it may support the biological infrastructure underlying attention, emotional regulation, sleep and ultimately resilience.

And perhaps, one of the most important health challenges of the 21st century will be learning how to preserve that flexibility in environments increasingly undermining it.

This perspective, invites us to reconsider how we think about mental health –  as the emergent property at the interconnection between the molecular, circuital, subjective and environmental levels.

Many difficulties with attention, anxiety or sleep are often framed as lack of discipline, poor time management or psychological weakness.. But in many cases we have seen that many of their emotional, cognitive or behavioural symptoms may actually be signs of something different: a stress system operating under sustained load and inadequate recovery. A system doing exactly what it evolved to do, but in an environment for which it was never designed for.

ADHD symptoms, anxiety, and insomnia are not always related, nor do they always share the same causes. But they may be understood as different expressions of a common challenge:

The progressive loss of physiological flexibility.

Health is not the absence of symptoms. It is the capacity to adapt and successfully engage with life challenges. In a world that increasingly competes for our attention, stimulates our emotions, and erodes opportunities for recovery.

Preserving that capacity may become one central goal of life in the 21st century.