Inadequate Personality Disorder: Definition, Traits & Treatment

Instructor: Sunday Moulton

Sunday recently earned a PhD in Anthropology and has taught college courses in Anthropology, English, and high school ACT/SAT Prep.

In this lesson, we will look at inadequate personality disorder. Although it is not part of psychological diagnosises today, we'll discuss its definition and traits as well as possible diagnoses today and their treatment.

What Is That?

If you've studied psychology for any length of time, you are probably thinking to yourself ''I've never heard of inadequate personality disorder!'' There's a reason for that. Unless you were studying psychology before 1980, you would not find this disorder in any of your textbooks because it only appeared in the DSM-II, the second edition of the Diagnostic and Statistical Manual of Mental Disorders published by the American Psychiatric Association (APA) in 1968. However, the term was in clinical use long before that. The DSM-II was replaced in 1980 with the much more influential DSM-III. However, inadequate personality disorder never appeared in any version of the manual after the DSM-II.

This mental health poster was printed around the time psychiatrists still used inadequate personality disorder as a diagnosis.

To understand the history and development of psychology as growing field, sometimes it's important to take a look back, and that's what we're going to do. Let's explore what little is said about this disorder and its symptoms, and then explore some of today's diagnoses that replaced it. Of course, we'll follow up with some of the treatment suggestions, both for then and for now.


Inadequate personality disorder was defined by the DSM-II as a pattern of behavior marked by weak and ineffectual responses to external stimuli of an emotional, social, intellectual, or physical nature. There is no obvious cognitive disability in patients with this disorder, but they have trouble adapting to new situations, tend to have low stamina both physically and emotionally, have difficulty mastering skills, and show both poor judgment and poor social skills. This is all the information given by the DSM-II. The clues to how we may diagnose it today lie in ineffectual responses, low stamina, and problems with adaptability, judgment, and socialization but the lack of information truly makes this a mystery.

Could It Be Autism?

In today's society, we may be overly conditioned to see autism in any disorder where socialization is a problem. In fact, many people have asked if this disorder is just another form of autism, and perhaps it is. Autism, also known as autism spectrum disorder, refers to a range of abilities or disabilities in the areas of communication, social skills, and adaptability. While some diagnosed with inadequate personality disorder may well have been autistic, the lack of physical stamina stands out as a symptom that may or may not be seen in autistic patients, depending on the degree of activity and interaction they engage in during their lives. Additionally, the description in the DSM-II indicates the person may have some challenges in life, but remains on the higher-functioning end of the autism spectrum, if that is their condition.

Autism and inadequate personality disorder share difficulties with social skills and responses to certain stimuli.

Could It Be a Brain Injury?

Another explanation for inadequate personality disorder may lie in brain injuries, particularly to the frontal lobe. In some cases, abnormalities in the frontal lobe can also be inherited. Evidence for this hypothesis comes from the famous case of Phineas Gage who survived a railroad spike penetrating his frontal lobe. The personality changes he exhibited often resembled inadequate personality disorder. We also see the same passivity and limitations in the historical description of patients after being lobotomized, a surgical procedure in which part of a psychiatric patient's prefrontal and/or frontal lobe is removed in order to curb their violent or erratic behavior. If patients with inadequate personality disorder inherited a frontal lobe abnormality or suffered a brain injury, this may explain what the disorder could be in today's terms. Luckily, we have brain imaging technology to identify frontal lobe abnormalities and injuries.

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