Autism Spectrum Disorder

In this episode, we walk through autism research one stop at a time, using an airport as our guide. 

We talk about what autism actually is and why it looks so different in every person. Why we diagnose something biological by watching behavior, and what that process gets wrong. What the genetics actually tell us and what they don't. Everything that travels alongside autism that most conversations completely miss. What the research says actually helps. And what adult life looks like for autistic people, including the hard numbers most people choose to skip over.

All of it from one paper. Lord et al., Autism Spectrum Disorder. The Lancet, 2018.

Transcript

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There's a moment that a lot of parents describe in exactly the same way. They're watching their child at a birthday party or a school picnic or just at the playground on a regular afternoon, and something feels off. Not bad, not wrong, just different. Their child isn't playing the same way as the other children. Or they're completely absorbed by one thing: a spinning wheel on a toy, a crack in the pavement, a pattern on the wall, while all the other children have moved on to other activities. Or they happen to be overwhelmed by something that no one else seems to notice. The noise, the light, maybe the sheer unpredictability of 12 children in a room. And most parents just stand there and think, is this just my kid? Is this a phase? Am I making something out of nothing? They take these questions to a pediatrician or a teacher or even the internet, and they get hundreds of different answers. Some of them are kind and some of them are not. But most of it is just noise. Here's what I want to do today. I want to cut through the noise, not with opinions, not with fear, but with one of the most rigorous, comprehensive reviews of autism research published in the last decade. A paper by Catherine Lorde and colleagues, published in The Lancet in 2018. I read it, I took it apart section by section, and I want to walk you through what it actually says, what autism is, how it's diagnosed, and why that process is more complicated than most people realize. I also want to walk you through what's actually happening in the brain, how the biological makeup of these children are different, what actually helps, and especially what adult life looks like. I think it's the most important part of the conversation and often most avoided. But before I get into the research, I want to give you a way of thinking about it. A mind map, if you will. I want you to imagine that you're planning a trip to Spain with your child. You sit down at the kitchen table, you spread out a paper map, and you walk through it together. Okay. We start here, we drive to this airport, we check in at this terminal, we go to this gate, and then we reach Madrid. Your child traces the route with their finger, memorizes it. Airport, terminal, gate, Spain. You think this information is clear, structured, predictable, right? You must feel confident, and your child is feeling confident. Now, I want you to imagine that your child walks into the airport and nothing seems to align with what they expected. Because everything around them is built around assumptions no one ever explained to them. And assumptions that you didn't even know existed. For instance, the signs are written assuming you can read quickly under pressure, that you can scan, filter, and move on in seconds. The PA announcements assume that your nervous system can pull one voice out of a wall of background noises and hold onto it long enough to act. And don't even get me started about the fluorescent lighting. It's constant, it's buzzing, it's humming at a frequency not everyone can tolerate. And the worst, asking for help, it assumes that you can read a stranger's face fast enough to know whether it's safe or not. Now, let's get one thing straight. Nobody built this airport to be cruel. They just built it for a specific kind of traveler and didn't think about everybody else. That's what growing up with autism in a neurotypical world can feel like. Not broken, not less, but navigating a system that was built around assumptions that just didn't include you. And most of the time being handed the same map as everyone else without being told that the airport has already changed. When you understand the airport, when you understand how it was built and why, you stop blaming the traveler. That's what this episode is about. We take one paper, we read it carefully, and we build something you can hold on to. I'm your host, Nafisa. I'm not a clinician, I'm someone who believes that good research deserves a wider audience and that most people, given clear and honest information, are capable of doing something meaningful with it. Today's paper is Autism Spectrum Disorder, a comprehensive review published in The Lancet in 2018. So let's get into it. We'll start at the front desk. That question sounds like it should have a simple answer, but it doesn't. And I think the reason it doesn't is actually the most important thing to understand before anything else. According to the review, autism spectrum disorder is defined by two core areas. First, differences in social communication, which essentially is how someone connects, initiates, reads, and responds in relationships. And second, restricted or repetitive patterns of behavior coupled with differences in how the sensory world is experienced. I'm gonna give you a minute to take that in. Those are the two pillars the diagnosis rests on. But within these two pillars, the range of how autism looks person to person is enormous. And the paper uses a specific word for this. It calls autism very heterogeneous. You might be wondering what it means. Well, heterogeneous means it doesn't look the same in every person, not even close. Some kids with autism are verbal, academically strong, in mainstream schools, and completely missed because they don't fit the image most people carry in their heads. Some of them have linguistic challenges or are non-speaking and will need significant daily support their whole lives. And some people, well, particularly women and children, learn to mask. They camouflage so effectively and so long that they arrive in their 30s or 40s completely exhausted, only to then get a late diagnosis. And some children can be identified as young as 15 to 24 months. That's right, months. The review says these early diagnoses should actually be monitored closely because the full picture at that age can still change. So, autism is not one route on the map, it's actually many overlapping paths, and the airport was built without a blueprint that accounted for all of them. Now, here's something I want to clear up before we go further into the review. The review clearly states that ASD results from early altered brain development. It is biological inorigin, it is not caused by parenting. I think it's important to shift the blame because there is none, especially on parents. The airport was just built differently from the beginning, and when you actually take that in, the shame, the guilt, the quiet blame, it starts to loosen. Not all at once, but it starts. And that's important. Now that we're all on the same page, let's scan what's inside. Biologically, of course. So let's move through security. If autism begins in the brain, if it's rooted in biology, why do we diagnose it by watching how someone behaves? Because the reality is there is no blood test for autism, no brain scan a clinician can point to, and no biomarkers. The review also says that. So what does that mean practically? It means that the clinician watches how someone communicates, how they play, how they respond to other people. They start looking for patterns and then compare those patterns to criteria in the diagnostic manual, usually also known as the DSM. But here's the thing: no matter how careful the observation or how trained the clinician, these observations are always filtered through the observer, through their assumption about what normal looks like, through their cultural context they were trained in, through the gender they were taught to expect autism in, through how much time they have in that room. So we're essentially watching how someone navigates the airport, but we're not inspecting the architecture underneath. And that one fact explains so much. It explains why children without language delays, or females from ethnic minorities, or individuals from lower socioeconomic backgrounds, or families who don't speak the language of the diagnostic system constantly receive later diagnosis. It explains why women specifically are underdiagnosed and identified later, partly because of the assumption that autism primarily occurs in males and partly because gender-related social differences can mask the features the system was trained to look for. This also explains the limitation. The paper names directly screening tools, because screening tools in general populations are typically not sensitive enough to identify most children with autism. Now, this was a lot of words, but what does it mean? Think about it this way: the security checkpoint was designed to flag a very specific kind of traveler. If your child moves through differently, if they've learned to mask, or if they don't fit the profile the system was trained on, the scanner might not catch them. That's not a fact about your child. That's a fact about the scanner. Now, you must be wondering if there are so many issues with getting a diagnosis, is it even worth it? And honestly, I would think so. Because for a lot of people, it's the first time they have language for experiences they've spent years calling personal failure. It also connects them to a support system, to a community, to an entirely different understanding of their own history. And that matters enormously because people then stop blaming themselves and finally accept that there are some things that just aren't in their control. The diagnosis is a map of observable behavior, but the person underneath is always more complicated than any map can ever be. Once you've crossed security, most airports move towards immigration. But we're gonna jump ahead to the end of our travel journey. We're gonna head towards the luggage carousel. This is the moment where everyone stands around and waits. You know the bag you came with, you just don't always know exactly how long it will take to reach you, or how it traveled. That's a pretty honest description of where genetic research is right now. So let's talk about what's actually happening underneath, in the brain, and in the genes, because this is the part of the conversation where most parents go looking for explanations and where they tend to find either too much certainty or too much fear. So let's be specific. How much of autism is genetic? The review cites a 2016 meta-analysis of twin studies that puts heritability between 74 and 93%. That's a pretty wide range, if you ask me. And that width matters because it tells you the science is still being refined. But the headline is always autism has a very strong genetic component. Now, if you just heard that and you've started tracing a family tree, I'd like to gently stop you. Heritability does not mean one bad gene. It does not mean one parent's fault, and it does not mean it was preventable. There is no single autism gene. What the research shows is something far more layered. Hundreds of different genetic variants, rare and common, some inherited, some arising fresh in the child, interacting with environmental factors in ways researchers are still mapping. The review describes it as complex inheritance, which are essentially just many common variants that each make a small contribution that are still not deterministic causes of autism. Sibling studies show that autism occurs in 7 to 20% of younger siblings after an older sibling is diagnosed, and that number rises when two older siblings are already affected. Risk is three to four times higher in boys than girls, though that gap may partly reflect underdiagnosis in girls rather than a purely biological difference. More than a hundred genes have been implicated so far. The most common disrupted gene in rare cases is called CHD8. But even CHD8 only accounts for less than half a percent of children with autism. That's how spread out the genes are. And then you take brain imaging and it adds another layer. Children with autism show a pattern of accelerated brain growth in early infancy, which just means larger brain volumes earlier than typical. This results in altered connectivity, broadly underconnectivity between distinct brain regions and local overconnectivity within specific areas, which are often the frontal and occipital regions. What that means practically is that different parts of the brain may not be coordinating in the same way they typically do, which may contribute to differences in sensory processing, social cognition, and language. All the things that eventually show up as behavior. Here's the honest version of the luggage metaphor. This isn't one bag with one clear thing in it. It's a whole collection of bags, some inherited, some that appeared from nowhere, packed with hundreds of small things that interact with each other in ways we're still learning to read. You can't look at the bag on a carousel and know what's inside. You have to unpack them carefully, and even then, what you find doesn't tell you where the traveler is going to end up. Because the review is clear about this, none of the genetic or neurobiological findings predict individual outcomes reliably. We can see patterns across large groups, but we cannot look at a child's genetic profile and say this is what their life is going to look like. Genetics tell us about the risk, about probability, not about destiny. And that distinction is everything. Let's circle back to our journey after you've cleared security. Let's look at the departure board. When you think about it, the departure board is one part of any airport that is usually packed with information that is moving quite quickly. But in order to make sure you can see your flight, you have to tunnel your attention into one specific item on the screen, which usually means you'll miss everything else. One of the things this paper does that I think is genuinely important and that most public conversations about autism miss is how seriously it takes everything that travels alongside autism. Because autism rarely travels alone. The most common co-occurrence is ADHD, present in about 28% of people with autism. More than one in four. ADHD does not sit quietly alongside autism. It actively shapes how someone regulates attention, builds peer relationships, and whether depression develops during adolescence. The review is explicit that this needs to be tracked over time, not just flagged at diagnosis and forgotten. Another common co-occurrence is anxiety. Social anxiety, generalized anxiety, separation anxiety, especially in younger kids, and specific phobias also affect many people with autism. The paper notes that anxiety and depression are more observable in verbally fluent individuals and both tend to increase during adolescence, particularly in girls. And the paper says this directly. Co-occurring difficulties like severe anxiety or depression can cause as much functional impairment as the core autism features themselves. Sometimes more. Research also states that irritability and aggression appear in around 25% of people with autism, higher than in other developmental disorders. And the forms vary enormously from minor physical outbursts in very young children to verbal aggression in adults. And then there are the physical co-occurrences, the ones that almost never come up in public conversations about autism, but are real and daily part of many people's lives. Sleep problems. Sleep problems affect 25 to 40% of people with autism. Furthermore, gastrointestinal symptoms affect approximately 47%. These children might also have restricted or rigid food choices, and I'm not talking about picky eaters, but I'm talking about sensory-driven responses with clinical weight that affect 42 to 61%. On top of that, epilepsy has a reported prevalence of 8.6%, particularly associated with intellectual disability and female sex. So when a parent says my child seems to be getting worse, I want this section of the paper to be somewhere in the room with that conversation. Because sometimes what looks like autism intensifying is actually untreated anxiety or ADHD or sleep problems or a gut issue or pain that the child just cannot find words for. If someone is struggling in the airport, if they cannot make the connection, it might not be the map. It might be everything else that's happening around them. And if you only focus on one flight on the board, you're going to miss what's actually making the journey hard. Let's move on to the runway. Everything we talked about before this was preparation. The check-in, the security, the gate. Let's talk about the question everyone actually wants answered. In reality, at any airport, the runway is usually longer than most people want to hear. But it's real. Let's look into what research says actually works. I want to be careful here, because this is the part of the conversation where the internet gets very loud and very wrong in both directions. People will tell you one specific intervention is everything. Other people are selling supplements, promising cures, and there are people on the other side who say nothing meaningful can be done. The Lancet review is more honest than any of that. So let's look at what evidence says actually works. For young children, the review focuses on Early parent-mediated interventions. These are programs where parents are coached not on what's wrong with their child, but on how to interact with them in ways that naturally support communication and connection. And the results are consistent across multiple well-designed trials, effect sizes at around 0.3. This is considered moderate by research standards. Not a miracle, but real. And one follow-up study found that those benefits extended into later childhood with an effect size of 0.7. And I think it's worth pausing on what these interventions are actually teaching. Because it's easy to misread them. They're not teaching children how to perform differently. They're teaching parents to slow down, to follow the child's lead, to create space for shared attention, for the child to initiate, for a connection to happen on the child's own terms. They reduce family distress and they build something real, connections. Then there is a category the review calls naturalistic developmental behavioral interventions, which are programs like the Early Star Denver model, Pivotal Response Treatment, and JASPR. These are more intensive, usually one-on-one with a therapist or teacher, and they show larger effects on specific scales. Meta-analysis report effect sizes of 0.69 for adaptive scales, 0.76 for IQ, and around 0.5 for language after two years of treatment. The review does, however, flag something important here. Only one of these trials was truly randomized. So the evidence is actually meaningful because it's measuring what's actually happening on medication, and I know this is something a lot of parents ask about. The review is very direct. Current pharmacology in autism treats co-occurring conditions, but not autism itself. So medicines such as Raspirodone actually have the strongest evidence for reducing irritability and agitation in children and adolescents. Both have real side effects though. They have sedation and weight gain being the most common. ADHD medications like methylfinidate, atomoxetine can help with ADHD symptoms, but they tend to yield less benefit and more harm to these individuals than the general ADHD population. So let's bring this back to the runway because the metaphor actually holds really well here. The goal isn't to put a different plane in the air, the goal is to improve navigation, to reduce the friction on the runway, to build skills that make takeoff more possible, and to invest in making the airport itself easier to move through. And I want to be really clear about something. No intervention removes autism. This is not the goal, and it is not the outcome. If someone is telling you that their program, their supplement, their approach will treat autism itself, not the anxiety that travels with it, not the sleep problems, not the ADHD, but autism as a condition, they are not working from evidence, and you deserve to know that. But for a lot of people with ASD, arriving at this gate is actually where the support system disappears. Everything was built around them. The school-based services, the therapy hours, the specialist appointments, the structured help. A lot of it ends around the time they turn 18. And what's waiting for them on the other side often wasn't designed with them in mind either. This is the section most people avoid. I think it's the most important one. So let's go through it honestly. 10 to 33% of adults with ASD use only simple phrases or do not speak and have IQs in the range of intellectual disability, often requiring very substantial daily support for their entire lives. In the US data, only about 25% of adults on the spectrum with average intelligence live independently. The rest live with family into at least middle age. Marriage and long-term relationships are still rare. And even though educational attainment has improved compared to, say, 20 years ago, employment has generally not kept up with those education levels. So if you're a parent listening to this, I understand that sitting with those numbers is hard. And I'm not going to gloss over them, but I want you to stay with me for a moment. Because how we frame this changes everything. Those numbers are not just a measure of what autism is, they are a measure of what autism is inside the system we have built. And those are two very different things. The review names developing services for adults with ASD as one of the field's most urgent priorities, because the drop in support after childhood is dramatic and the consequences are real. Think about it this way: all that scaffolding, the therapy hours, the school support, the specialist input, it largely disappears at 18, at exactly the moment when life gets the most complex. The social demands, the professional demands, the expectations of independence, all of that increases and the support decreases. The map doesn't disappear when the plane lands. The traveler still has to get somewhere. They still need to navigate their way out of the airport, find transport, build a life in a place that wasn't designed with them in mind. But if the airport stops updating its signs the moment they arrive, if the support ends right at the gate, then what comes next isn't a reflection of capability. It's a reflection of what the airport stopped providing. And I don't want to leave you with only the hard part, because there is more to this picture. A community sample found that about a third of adults with ASD who were diagnosed as children, specifically those with average or higher intelligence, no longer met diagnostic criteria in adulthood, though many did have minor psychiatric conditions. And the research on what predicts better adult outcomes is genuinely encouraging. Language and nonverbal skills by age 3, peer friendships and social engagements by age 9, and parent participation in early intervention, even as few as 20 sessions in a year, consistently predicted higher IQ, better academic achievement, and stronger adaptive skills in young childhood. So what does all this mean? It means that outcomes are not fixed at the moment of diagnosis. They are shaped by biology, yes, but also by the quality of support, by the environments people move through, and by the systems that show up for them. Airports can be redesigned. They just actually have to build it. Okay, so that was a lot of information. So let's summarize. What does the paper actually tell us? It tells us autism is biologically rooted, behaviorally diagnosed, genetically complex, and lifelong. It is not one path, not one severity, not one outcome, not one story. It is a condition that exists inside systems, diagnostic systems, educational systems, economic systems, and those systems shape what a person's life looks like just as powerfully as biology does. If you're a parent listening to this, your child is not failing to follow the map. They are navigating an airport that was built without them in mind. That is not their fault, and it is not yours. Please hold on to that. If you're someone who received a late diagnosis or you think you might have autism, or you're just now finding a language for experiences you've been carrying your whole life, this research is for you. You're not an outlier, you are part of what the spectrum actually looks like. The system just wasn't looking for you. And that is a failure of the system, not a reflection of you. And if you're here because you simply want to understand, because you want to be the kind of person who knows enough to actually show up for someone, that is exactly what the show is for. Outcomes change when environments change. That is not optimism, that is what the data shows. And just like that, airports can be redesigned. They just have to be built brick by brick. That is how the show grows. And that is how this research reaches people who wouldn't otherwise find it. Next episode, we're going deeper into autism. This time into the sensory experience and the nervous system. What's actually happening when the world feels like too much. The research behind that is more specific and more validating than most people realize. So I guess I'll see you then. Oh, and don't forget to follow me on Instagram at brickbybrick. Thanks for listening.