What Does Habituation Mean?

By Bradley C. Riemann, Ph.D. - Director, OCD Center at Rogers Memorial Hospital

Exposure and ritual prevention (ERP) has been found to be very effective for treating obsessive-compulsive disorder (OCD) over the last 35 years.  We know that as many as 85% of people with OCD can be helped by using ERP.  However, many OCD sufferers and their families are confused by some of the terminology associated with this technique.  One very important term that confuses many is “habituation”.  My goal in this brief article is to help clarify what this term means.

ERP is based on the principle of habituation.  By nature, people habituate to negative things around them.  In a sense, habituation means getting “used to” something we don’t like.  For example, after being in a room for a period of time we no longer hear the hum of a fan that we first found distracting.  The sound does not go away; we just got used to the sound and therefore no longer perceived it.   Another example of habituation we can all relate to is water temperature.  When we first jump into water we may find that it is cold, but if we stay in it long enough we find that the water has “warmed up”.  Again, the water hasn’t warmed up; we have just gotten used to it or habituated to it.  If you were to get out of the water for a while and jump back in, you would find the water to be as “cold” as it was the first time.  The process of habituation is normal and natural, and takes no effort on our part to occur.

So what does this have to do with anxiety and ERP?  With respect to anxiety, habituation refers to the decrease or reduction in anxiety with nothing but the passing of time.  Meaning, our anxiety about something we fear will eventually go down without doing anything, but letting time pass.  In ERP we look for two types of anxiety habituation.

First, there is “within trial” habituation or reduction of anxiety.  A “trial” in ERP refers to an exposure assignment you are attempting (e.g., touching a doorknob and not washing your hands).  Within trial habituation is the reduction in anxiety you get while holding onto the doorknob over a period of time (e.g., your anxiety reduces from a 4 to a 2 using a 10-point scale in 10 minutes).  You will get this anxiety reduction if you give yourself long enough, without doing (e.g., washing your hands), thinking (e.g., thinking to yourself a prayer), or saying (e.g., asking if it is ok to touch a doorknob) anything.  Your anxiety goes down with nothing more than the passage of time.

The key to within trial habituation is to do the exposure exercise long enough to experience this reduction in anxiety.  Using the water temperature analogy again, you must stay in the water long enough so it can “warm up”.  How long is long enough?  It is different for different people, and it is different for different exercises.  Most doctors would encourage you to do the exercise until you get at least a 50% decrease in your peak anxiety rating (i.e., when it was at its highest point during the trial, say from a 4 to a 2).  Typically, the more challenging the exposure exercise is for you the longer it will take to experience within trial habituation.

The second type of habituation sought in ERP is “between trial” habituation.  This refers to the reductions in the “peak” anxiety ratings you experience when you repeat the exposure exercise over and over again.  The within trial reductions in anxiety that we have already discussed do not last long if the exposure exercise is not repeated.  Meaning if you successfully saw your anxiety go from a 4 to a 2 in 10 minutes on a particular exercise and then waited a week before you did it again, you probably would get an anxiety rating of a 4 to a 2 in 10 minutes again.  The end result is nothing has changed without repeating the exposure exercise in a time-intensive enough fashion.  It’s like getting out of the water and not going back in until the next day.  Chances are it will feel as cold as it did the day before.  It takes repetition to get your peak anxiety ratings to reduce from one trial to the next.  With enough repetition you can get to the point where an exposure exercise will cause you minimal anxiety from the start of that exercise.  How many repetitions will it take before you experience minimal anxiety from an exercise?  It is different for different people and different for different exercises.

Between trial habituation is the “treatment effect”. It produces the overall reduction of the peak anxiety ratings.  Rituals or compulsions give you the equivalent of “within trial habituation”.  Compulsions work, and can work to reduce anxiety quickly (e.g., driving anxiety from a 4 to a zero).  Obviously, the problem is that they don’t help in the long run and every time someone is faced with that same situation they will have to ritualize again.  Exposure without repetition is the same thing.  It reduces anxiety at first but if you don’t keep doing it nothing good happens in the long run.  ERP “beats” compulsions with the between trial reductions or habituation that occurs with repetition.  In a sense the goal of ERP is to replace the compulsions with the process of habituation as a means of reducing anxiety.

So, when doing ERP, remember to do the exercise long enough to get within trial habituation, and repeat it enough times to get between trial habituation.  Good luck!