What Does "Rule Out" Mean?

Understanding How an Accurate Diagnosis is Made

Man talking to his psychologist
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The term rule out is used by mental health professionals in determining the most accurate diagnosis to explain the problems your teen is having. 

Figuring Out the Right Diagnosis

Finding an accurate diagnosis for troubled teens can be difficult and initially several possible mental health disorders may seem to explain your teen's emotional or behavioral problems. Because of this, the process of finding a correct diagnosis is conducted in a logical, step-by-step manner that considers all the possibilities, and then narrows them down to the diagnosis or diagnoses (sometimes more than one) that most closely match your teen's symptoms.

Getting the right diagnosis is extremely important in order to be able to successfully treat your teen's symptoms. It's a mental health professional's job to use different methods to figure out exactly which disorder in the Diagnostic and Statistical Manual - 5 (DSM-5) fits your teen best. 

An Example of the Difficulty of Diagnosis

For example, an extremely defiant teen may suffer from oppositional defiant disorder, depression, or he may be abusing drugs or alcohol. A defiant teen could also be heavily influenced by peers who are engaging in criminal activities, or possibly the teen has been molested but hasn't told anyone.

The mental health professional evaluating this teen is likely to say, “First we will rule out depression, then we will consider other possibilities.”

Through this process, which is also done with medical conditions, the most accurate diagnosis is reached through a process of elimination, determining the best diagnostic fit by methodically discarding the ones that do not fit.


Steps Mental Health Professionals Use to Rule Out Diagnoses

  1. First, the mental health professional, or clinician, has to figure out what your motivation is for getting a diagnosis for your teen. Does your teen seem to be looking for a diagnosis in order to get out of work or school or does she appear to need a diagnosis for psychological reasons rather than for real relief?
  1. Secondly, the clinician needs to make sure your teen is not abusing drugs or alcohol because this abuse could be causing the symptoms. If there is substance abuse involved, the clinician needs to figure out if your teen's symptoms are due to the substance abuse or if he is abusing the substance because of the psychiatric symptoms.
  2. The next step is ruling out a medical condition as the cause of your teen's psychiatric symptoms. For example, an untreated thyroid condition can cause depression. 
  3. The fourth step is to decide what your teen's specific primary disorder could be using the criteria in the DSM-5. This is done by comparing symptoms for specific disorders and ruling out the ones that don't fit.
  4. If your teen's symptoms are significant and causing problems, but not severe enough to warrant the diagnosis of a specific primary disorder like depression or generalized anxiety disorder, the next step is to figure out if your teen has "adjustment disorder" or "other specified/unspecified disorder." If your teen is diagnosed with adjustment disorder, this means she is having a bad response to a psychological stressor, such as a loved one's death. If adjustment disorder does not fit, the clinician may choose other specified/unspecified disorder instead.
  1. The last step is for the clinician to decide how much your teen's symptoms are impacting his life. If they are significantly impairing his everyday activities, the clinician will likely decide to diagnose the disorder from step four, such as depression or obsessive-compulsive disorder (OCD). The clinician also has to differentiate between a disorder and psychiatric symptoms from something like losing a loved one. Not adjusting well to the death of your mother, for example, does not necessarily mean that you have major depression, though it may cause distress.    


LeBano, Lauren. "Six Steps to Better DSM-5 Differential Diagnosis." Psych Congress Network (2014). 

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