Signs of Autism in Adulthood

When doubts about autism arise later in life, it’s often because of persistent misconceptions and stigma surrounding autism spectrum conditions. And what doesn’t help is how vague some of the diagnostic criteria can seem.

So here are a few concrete examples that may point towards autism in adulthood:

(Important note: these traits are not diagnostic criteria, but rather common patterns observed in patients that may help you explore your doubts and prompt a conversation with a professional.)

You had a period of crisis when entering secondary school.

Autism is highly contextual. Although we often use examples from childhood to describe signs of autism, most adults diagnosed later in life report that they felt “less autistic” as children. Medically speaking, they were of course not “less autistic”—but the environment around them may have cushioned some of the challenges linked to autism.

In adults who had a “typical” childhood—without major trauma and in a relatively secure environment—starting secondary school or sixth form often meant a sudden and drastic increase in mental load and social demands. This often led to repeated crises that may have been identified at the time as burnout or depressive episodes.

Suddenly needing to change classrooms, find your way around, memorise as many faces as subjects, and overthink how to interact with every new teacher—this creates an overwhelming mental burden, especially when it all hits at once.

You rehearse conversations in advance—and replay them afterwards.

We often hear about “communication deficits” in autism, but I find the term inaccurate. What autism actually involves is not a lack of communication skills, but the fact that social codes and norms aren’t intuitive. That doesn’t mean an autistic person is “worse” at communicating—it means it's an invisible mental workload.

Most adults diagnosed with autism have one thing in common: they mentally rehearse conversations beforehand. They imagine the scene again and again, running through every possible scenario to have the right response ready for each case. Whether it's a phone call, a meeting, or just a quick chat with the baker—conversations are often practised in advance.

And afterwards? The same conversation is mentally replayed and dissected, often with a sense of “I should have said/done this instead.”

Yes—exactly like an elite athlete visualising the competition and then analysing it in detail to improve. In my view, it’s more about over-intellectualisation than any kind of deficit.

There's a huge gap between what you do easily and what you struggle with.

Since childhood, you may have noticed that your abilities are scattered in a way that seems “illogical” to others.

One of my patients, for instance, cannot cope with small talk—it triggers intense panic sensations. Yet she can deliver a complex presentation in front of 600 people. Both involve speaking, but for the autistic brain, they’re entirely different.

Small talk feels like a high-stakes oral exam in “being normal,” and offers no benefit other than social conformity—which is both pointless and anxiety-inducing for the autistic mind. But informing 600 people about something that matters to her activates her brain’s natural role as an accumulator and sharer of knowledge.

Ask yourself whether you notice these sorts of contrasts: struggling to get your driving licence, or to reply to messages promptly, but having no trouble memorising complex information or understanding how a tricky tool or system works. (These are just a few examples.)

You have an unusual relationship with temperature.

This may seem like an odd sign, but it’s actually reported by many people across the spectrum. You might dislike eating or drinking things that are too hot—or on the contrary, only feel comfortable in scalding-hot baths. You might avoid wearing a coat in winter, or sleep under a duvet in the height of summer. You’ve probably noticed that your sense of hot and cold often differs from that of those around you.

Chit-chat and conversation feel different for you.

Talking about nothing in particular—“small talk”—can be extremely uncomfortable depending on your level of fatigue. But start talking about something you’re passionate about, and suddenly you could chat for hours.

This is, again, one of the major contrasts typical in autism. As mentioned earlier, small talk is an anxiety-inducing and pointless exercise for the autistic brain. In contrast, sharing useful or interesting information is one of its main strengths and motivations.

This contrast often complicates diagnosis in adulthood. Because genuine conversations feel enjoyable, both patients and clinicians may overlook the fact that social situations can be exhausting or difficult.

So if all this sounds familiar—what next?

First of all, don’t panic! These are not diagnostic criteria, but common traits observed in autistic adults. It’s entirely possible to identify with each one and for it to stem from personal experience. But it’s also possible that they form a pattern suggestive of autism.

You can explore this further through self-assessment tools (there are some relatively reliable ones available like teh RAADS-R), or you can reach out to a therapist or psychiatrist specialised in autism to discuss your questions.