Signs of autism and ADHD in adults that are often missed

Many adults spend years feeling that they work differently from the people around them. They cope. They get on. And they wonder why everything takes so much effort. Sometimes autism or ADHD is part of the explanation, and sometimes it is not. This page describes signs of autism and ADHD that are easy to miss, so you can decide whether you want to look into it.

A note before you read

Nothing on this page is a diagnosis, and you cannot confirm autism or ADHD by ticking off a list. Almost everyone recognises some of these signs at times. Stress, poor sleep, anxiety, low mood, physical health problems, trauma and a demanding life can all cause similar things.

A diagnosis comes from a careful assessment by trained professionals, not from an article, a quiz or a social media video. If something rings true, the end of this page explains what you can do next.

Why adults are often missed

Autism and ADHD are neurodevelopmental conditions, which means differences in how the brain develops. Clinicians look for signs that began in childhood and have carried on into adult life. Even so, many adults reach their thirties, forties or later without a diagnosis.

Some learned to cope well enough that nobody noticed the effort. Some were assessed as children against a narrower picture than clinicians use now. Some were treated for other difficulties first.

Signs of autism that are easy to miss

The NHS lists well-known signs, such as difficulty with social communication, a preference for fixed routines, distress when routines change, repetitive movements, a strong focus on particular interests and sensory differences. It also says that masking can make signs less noticeable. Quieter versions are easier to miss.

• Social effort that stays hidden. You may hold a conversation without obvious difficulty, yet find it tiring and rehearse it beforehand. Researchers call this “camouflaging”: hiding or making up for autistic traits, for example by copying other people’s expressions or steering a conversation with questions. Autistic adults have described feeling exhausted and anxious afterwards, and some say it was one reason their needs went unrecognised for longer.
• Sensory experiences. Sound, light, touch, taste or smell may feel stronger than they seem to for other people, or weaker. Clinicians are asked to consider this, along with close attention to detail. You might avoid busy shops, find it impossible to concentrate near a humming fridge, or not notice pain or hunger.
• A need for routine and predictability. Distress when plans change is a feature clinicians look for. In adults it is often put down to being “particular” or “set in my ways”.
• Trouble keeping work or relationships steady. Difficulty keeping a job or course, or forming and keeping relationships, are among the things that may prompt an assessment. They do not show autism on their own, and they have many causes. They are part of the picture clinicians consider.

Signs of ADHD that are easy to miss

The NHS describes adult ADHD as including inattention, such as being easily distracted or forgetful, struggling with time management or finishing tasks, and often losing things. It also includes restlessness, talking over others and acting on impulse. Most adults have a mix of both, though some have only one.

• Inattention without hyperactivity. Some adults never seem restless. The difficulty is on the inside: a mind that drifts, a pile of half-finished projects, a gap between how capable you feel and what you manage to finish.
• Strong emotions. Researchers have argued that difficulty managing emotions may be a core part of adult ADHD, not a minor extra. People often describe quick frustration, strong reactions that fade as fast as they arrived, or feeling overwhelmed by small setbacks.
• Planning and organisation. Running late, missing deadlines, struggling to start tasks or keep paperwork in order can all be put down to character. If these difficulties have been there since childhood and affect daily living, they are worth discussing with a clinician.

Burnout and exhaustion

Some autistic adults describe long-lasting exhaustion, losing skills they used to have, and less tolerance for sensory and other kinds of stimulation. Early research suggests it may be different from both workplace burnout and depression. People who have been through it say that acceptance, support and being able to stop masking helped them recover.

If this sounds familiar, it deserves to be taken seriously. Talking it through with a professional can help.

When it gets mistaken for something else

Anxiety and depression are real, and they are common alongside both conditions. The NHS notes that adults with ADHD often also have depression or anxiety.

The difficulty comes when the autism or ADHD underneath is not considered. Some autistic adults say they were given a mental health diagnosis, most often a personality disorder, that they later felt was wrong. That is why a thorough assessment looks at your whole life, not at one symptom.

Autism and ADHD together

They are separate conditions, but they often overlap. NICE notes that people with other neurodevelopmental conditions, including autism, may be more likely to have ADHD. Reviews suggest that roughly three to four in every ten autistic people also have ADHD. Estimates differ, and they are not specific to adults.

Having both can be confusing, because traits may seem to pull in different directions, such as a wish for spontaneity alongside a need for predictability. A clear assessment can help make sense of this.

If you want to find out more

Start by noticing what is hard, how long it has been hard and what helps. It can be useful to jot down examples, and to think about whether anyone who knew you as a child could describe your early years. Assessments for both conditions usually draw on your history from childhood onwards, and may involve someone who knows you well.

Through the NHS. Speak to your GP, who can discuss a referral to a local service. The NHS says an assessment can take months or longer once a referral is accepted, and that your GP can advise on support in the meantime. If you are not happy with the response, you can ask to see another GP. Our page on NHS and private assessment explains the differences in more detail.

Privately. Curious Minds offers in-person assessments in Dundee. They are delivered by clinical psychology, nursing and prescribing, and speech and language therapy professionals, across six pathways. The first step is a free 20-minute phone consultation, where you can ask questions and decide whether to go ahead. There is no obligation.

You can read about adult autism assessment, adult ADHD assessment or the combined autism and ADHD assessment. There is also information on neurodiversity screening. Answers to common questions are in our FAQs, and you can reach us through the contact page.

There is no deadline and no right answer. Understanding how you work is a reasonable thing to want, and you do not need to be in crisis to ask.

This page is general information. It is not a diagnosis or medical advice.