Checking doors and locks in OCD: why one check does not feel enough

The door is locked, but the doubt continues

Checking a door before leaving is an ordinary precaution. In OCD, the check does not end when the information has been obtained. The person sees that the lock is engaged, pulls the handle or remembers turning the key, but another question appears: ‘Did I check it properly?’, ‘What if it opened?’ or ‘What if I only think I did it?’

They may know that the door is locked while being unable to feel sufficiently certain to leave. This difference between knowing and feeling certain helps to explain why saying ‘but you have just checked it’ does not resolve the problem.

How the sequence develops

Checking may include looking, touching, moving the handle, counting turns, taking a photograph, repeating a phrase or asking another person to confirm. Some people follow the same order every time. If they are interrupted, speak or cannot remember the action clearly enough, they begin again.

Doubt may increase after they move away and create a need to return. To hide these journeys, a person may leave home early, avoid being the last to leave or make somebody else responsible for locking up. The compulsion occupies more than the minutes at the door: it alters timetables, journeys and family decisions.

Why more checking can produce less confidence

In a well-known experiment, repeated checking did not improve memory accuracy, but it reduced vividness, detail and participants’ confidence in their memory. Repetition makes each check resemble the previous ones. It then becomes harder to distinguish the most recent check, and the memory can feel blurred.

This finding does not mean that every memory doubt is OCD or that checking always creates the problem. It does help to explain a common paradox: checking in order to feel more certain may eventually make the memory feel less trustworthy.

Proportionate precautions and compulsions

Checking a faulty lock, following a safety procedure or confirming a door when there is a genuine risk is reasonable. Checking becomes concerning when it continues after a sufficient answer has been obtained, follows rigid rules, consumes substantial time or prevents the person from leaving and continuing with the day.

Family members may become involved by looking again, sending photographs or answering repeatedly. This reduces distress in the short term, but can transfer the check to somebody else. Abruptly withdrawing all help may also produce a crisis. Changes are best agreed at a calm time and, when the problem is severe, with professional guidance.

Treatment and seeking help

Cognitive behavioural therapy with exposure and response prevention — ERP — is a recommended treatment. Work may involve carrying out one proportionate check and practising walking away without returning, taking a photograph or asking for confirmation. The difficulty is graded and adapted. It does not involve leaving doors open or ignoring genuine risks.

Help is advisable when checking causes delays, requires journeys back home, prevents sleep or leaving, produces conflict or expands to locks, appliances, messages and other tasks. A professional should also consider whether memory, attention, health or other difficulties require a different approach.