Yet sometimes the two conditions can help and complement each other – for example, the ADHD traits can make a person with autism more sociable and the autistic traits can help the ADHD person concentrate and focus.

“The way I describe it is that autism can be like a parent to ADHD, as it does not let it become too anarchic or disorganised,” says Dr Sadiq. Whereas “ADHD is like a friend to autism and does not let it be too reclusive.”

How are autism and ADHD connected?

Autism and ADHD are both neurodevelopmental disorders. They share some traits and have a strong genetic link, yet exactly how they’re connected is not yet clear.

Some researchers believe that they sit on a spectrum of neurodiversity in which different symptoms appear at different times; others believe that eventually, we will understand AuDHD as a separate diagnosis.

Dr Fleur-Michelle Coiffait is a consultant clinical psychologist with expertise in autism and ADHD. “The more I work in this area, and the more clients I see, the more I think AuDHD isn’t just one plus the other – it has unique challenges,” she says.

Common traits of AuDHD

Several traits of both ASD and ADHD show up in AuDHD. Not everyone will have all of these symptoms, however. “In some people, the autism might be more prominent, in others the ADHD might be very strong,” says Dr Sadiq.

The traits of AuDHD include:

Social challenges

“Generally we find that people with ADHD get a lot from social interaction, but AuDHD people might find they have more autistic-style social challenges,” says Dr Coiffait. This might look like having no filter and blurting things out; craving social situations but finding it hard to understand others; or getting easily overwhelmed and tired, but finding it tough to slow down and recharge.

Inattention and hyperfocus

Some may struggle to focus on things that they’re not interested in, but may “hyperfocus” on some special interests or when driven by a deadline.

Sensory differences

They may be over or under-responsive to sensory stimulation, such as noise, light, and touch, and may struggle with certain foods or strong smells.

Impulsivity

“Impulsivity may be driven by the ADHD search for stimulation or the autistic frustration when things don’t happen at a specific time,” Dr Sadiq says. It can lead to relationship problems and addictive behaviours towards drugs, alcohol, food, gaming or gambling.

Stimming and fidgeting

Fidgeting, stimming (repetitive movements or sounds that people use to cope with their emotions) and verbal tics can be a product of ADHD restlessness or an autistic attempt to soothe themselves.

Emotional regulation

Difficulties with emotional regulation may lead to emotional outbursts.
“Often autism and ADHD are pulling them in two different directions, they’re navigating that within themselves and that can be very draining,” says Dr Coiffait. “They may spend a lot of time masking and behaving how they feel they should behave in situations, being a bit of a chameleon, which can impact your mental health.”

The impact of AuDHD on daily life

Living with undiagnosed AuDHD can lead to burnout, recurring stress-related health problems and anxiety.