Executive function and ADHD, explained simply

What it is

Executive function is a name for the mental skills that run the show. They’re what you use when you plan your morning, keep a phone number in your head, stop yourself saying the first thing that comes to mind, or change plans when the train is cancelled.

Researchers usually describe three core skills.¹

• Working memory. Holding information in mind and working with it. Remembering why you walked into the kitchen. Keeping the three things you need from the shop in your head while you drive there.
• Inhibition. Stopping yourself. Not picking up your phone. Not acting on the first impulse. Staying on the thing you chose rather than the thing that’s loudest.
• Cognitive flexibility, or shifting. Changing tack. Switching from one task to another, or seeing a problem a different way when the first way isn’t working.

These three are related, but they’re separate skills. A well-known study found they could be measured apart, and that each one played a different part in harder tasks.² From them, more complex skills are built, like reasoning, problem solving and planning.¹

Planning a day uses all of it. You hold your tasks in mind, guess how long each will take, put them in an order, stop yourself drifting, and change the plan when something runs over.

How ADHD relates

A large meta-analysis pooled 83 studies comparing people with and without ADHD on executive function tasks. On average, the ADHD groups found every type of task harder. The clearest differences were in response inhibition, vigilance, working memory and planning. These differences weren’t explained by intelligence.³

The same review is careful to say these weaknesses aren’t found in everyone with ADHD. They’re one important part of the picture, not the whole of it.³ So if you have ADHD and you’re great at planning but terrible at stopping, or the other way round, that fits.

One influential model, from the psychologist Russell Barkley, puts inhibition at the centre. In it, difficulty with inhibition knocks on to working memory and to managing your own emotions and motivation.⁴ It’s a model rather than settled fact, and Barkley himself said far more research was needed. But many people with ADHD find it describes their days well.

What it feels like

You know exactly what you need to do, and you still don’t do it. You make a plan in the morning and lose it by eleven. You start three things and finish none. You forget the thing you said you’d do the moment you put the phone down.

It isn’t about knowing. Most people with ADHD know what they should be doing. The hard part is doing it at the right moment.

Why “just try harder” doesn’t work

Using executive function takes effort. It’s easier to carry on doing what you’re already doing than to change course.¹ For someone whose executive function is already working hard, every extra demand costs more.

It also gets worse under pressure. Stress, poor sleep, loneliness and lack of exercise all make executive function worse, for everyone.¹ So the day you’re most behind and most stressed is the day trying harder is least likely to work.

That’s why so many planners don’t stick. A paper diary or a long to-do app asks you to remember to look at it, work out what matters, guess how long things take and decide what to do next. Those are the exact skills that are struggling. A planner that relies on willpower is asking the tired part of your brain to do more.

Putting the plan outside your head

If holding things in mind is hard, stop holding them. Put them somewhere you can see.

That’s the idea behind a lot of adult ADHD therapy. In one well-known trial, adults were taught to use a calendar and a task list and to break overwhelming tasks into steps. They improved more than a group who had relaxation and education sessions instead.⁵ Another programme taught planner skills, scheduling and prioritising, and reminders such as “out of sight, out of mind”. It also beat supportive therapy in a trial.⁶ In the UK, NICE guidance says that when non-drug treatment is right for an adult with ADHD, it should at minimum include a structured supportive psychological intervention focused on ADHD, with regular follow-up.⁷

What helps

• Empty your head first. Get every task out and onto a list before you try to organise anything. The brain dump guide shows how.
• Make the plan visible. A day drawn to scale shows you what fits, so you don’t have to work it out in your head.
• Let something else do the sorting. If planning is the hard part, say your day out loud and let a tool put it in order. Then you check it rather than build it.
• Plan when you’re fresh. Executive function is better when you’re rested. A few minutes on a Sunday plan can save effort on a busy Wednesday.
• Expect the plan to change. Changing it isn’t failing. It’s what plans are for.

If executive function problems are making daily life hard, your GP can talk to you about assessment and support.