DSM Terminology Explained

The DSM sometimes uses phrases that may not be all that clear to people outside the mental health professions. So before we look in detail at the criteria for diagnosing autism, I thought it might be a good idea to run through some of the words and phrases that pop up a lot in the DSM.

DSM terminology

Qualitative impairment:

A problem with how the behaviour occurs

Quantitative impairment:

Whether or how often the behaviour occurs

Appropriate to developmental level:

Expected from kids or adults at that same age or stage of development

Stereotyped patterns:

Behaviours commonly seen in autism


Happens naturally without prompting



Qualifier definitions


The behaviour is not present at all

Failure to develop:

The behaviour hasn’t progressed


The behaviour is developing but later than usual


The behaviour is present but not in the usual way

An example of the use of qualifiers: Spoken language

Lack – the person doesn’t speak at all

Failure to develop – the person started babbling as an infant but stopped there

Delay – the person is getting better at making words and putting them together into sentences, but is behind where they should be for their age

Impairment – the person uses speech but doesn’t use the words correctly

14 May, 2012 by Bec Oakley

Bec Oakley is an autistic writer and proud parent, with an intense passion for 80s text adventures, Twizzlers and making the world a better place for autistic people and their families.