What is the Zeigarnik effect, and how does it relate to ADHD? 

Have you ever found it hard to stop thinking about something you haven’t finished like an email draft, a half-done report, or a forgotten message? This mental “unfinished business” is known as the Zeigarnik effect, a psychological phenomenon first described in the 1920s. It refers to the brain’s natural tendency to hold onto incomplete or interrupted tasks, keeping them active in working memory until they are resolved. For many adults with ADHD, this effect can feel amplified, leading to mental clutter, stress, and difficulty switching focus. 

How the Zeigarnik effect links to ADHD 

According to NICE guidance (NG87, 2025) and NHS ADHD resources, adults with ADHD experience executive dysfunction difficulties with working memory, planning, and organisation. These challenges make it harder to prioritise or complete tasks, leaving several unfinished projects active in the mind. The Royal College of Psychiatrists notes that this ongoing mental load can lead to overwhelm, anxiety, and burnout. 

Neuroscientific studies also show that dopamine regulation in ADHD affects how rewards and closure are processed. Because the brain struggles to gain satisfaction from partially completed work, unfinished tasks stay mentally “open,” causing restlessness and intrusive thoughts. 

Techniques to manage the Zeigarnik effect in ADHD 

The NHS and NICE recommend cognitive behavioural therapy (CBT) for ADHD to improve task planning and closure. Techniques that help include: 

Task chunking  

Breaking projects into smaller, clearly defined steps and marking each as “done” to achieve mental closure. 

Time blocking  

Scheduling set times to complete or review tasks prevents them from remaining mentally open. 

Completion logging  

Writing down what’s finished gives the brain a reward cue, helping release cognitive tension. 

Body doubling  

Working with someone else creates accountability and helps bring tasks to completion. 

If you often feel mentally “stuck” on unfinished work, an ADHD assessment can help identify the role of executive function and focus difficulties. ADHD Certify provides affordable online ADHD assessments for adults and children in the UK, offering expert diagnosis, medication reviews, and ongoing support. 

Key takeaway 

The Zeigarnik effect explains why unfinished tasks can weigh heavily on adults with ADHD. By using structured completion strategies, therapy, and professional support, you can reduce mental clutter, feel more in control, and experience the satisfaction of finishing what you start.