Parking a stray thought: mind wandering and what to do

You are halfway through something and a thought arrives: an email you forgot, an idea, a worry. Following it costs you your place. Ignoring it costs effort and often fails. A common suggestion is to “park” it: write it down and return to what you were doing. The research on mind wandering in ADHD is fairly consistent. The research on parking is thinner and mostly borrowed from other fields.

What the evidence says

The mind wandering linked to ADHD is the unplanned kind. In two large non-clinical samples and a clinical one, it was spontaneous mind wandering, not the deliberate kind, that was central to ADHD symptoms ¹. A systematic search found only nine studies that met its criteria; they suggest ADHD is frequently associated with spontaneous mind wandering and that this kind of mind wandering comes with more functional impairment ². In adults with ADHD, mind wandering contributed to impairment independently of the core symptoms ³.

It depends on the task. In a small laboratory study, adults with ADHD reported less mind wandering as demands on working memory increased, but not during tasks that required sustained attention ⁴.

Even a short interruption has a cost. In one experiment, interruptions averaging 2.8 seconds doubled the rate of errors in a task with ordered steps ⁵. In another, a phone notification alone, without the person touching the phone, disrupted performance on a demanding task ⁶.

Writing things down helps you come back. In a simulated air traffic control task, people were less likely to remember a deferred task as the wait got longer. Interruptions did not affect whether they remembered it, and the authors concluded that memory can hold up against interruptions when the environment provides cues and a way to offload ⁷. Across 33 laboratory experiments, steps taken to manage interruptions improved accuracy on the main task and shortened the time it took to resume ⁸.

What we don’t know

None of the interruption studies above were done with people with ADHD, and we found no trial of a “distraction pad” or “parking lot” in adults with ADHD.

What exists is not encouraging on its own. In one clinic’s report on a therapy programme for adults with ADHD, all 14 participants in one group said the module on distractibility had been of no benefit ⁹. That is a small observational report about a whole module, not a test of writing thoughts down.

Things to try

• Write it down in a few words and go back. The aim is to give the thought somewhere to wait, so that you do not have to hold it ⁷.
• Give worries an appointment. In a trial with people who worried a lot, limiting worry to one 30-minute period at a set time and place each day reduced worry, anxiety and insomnia more than the comparison approach ¹⁰. In another trial, adding a plan for when and how to deal with the postponed worry cut worry time by about 15 minutes compared with postponing alone, though sleep did not improve ¹¹. Both trials involved people who worried a lot, not people with ADHD.
• Write before something stressful. Students who wrote about their worries just before an important test scored higher, especially those who were usually anxious about tests ¹².
• Silence alerts while you work. A notification can interrupt you even if you never pick up the phone ⁶.