Psyc 238 Lecture 1.4: Classification of Maladaptive Behavior

Classification

• subdividing or organizing a set of related objects

• a shared scientific language

What are the benefits of classification?

• a shared scientific language

• Facilitates description, helps us easily know what a patients symptoms and history are

• Aids treatment decisions, prognosis

• Facilitates research on etiology (causes), and treatment

• Facilitates 3rd-party reimbursement (allows us to bill insurance)

The Rosenhan experiment

Fake participants submitted themselves for evaluation at various psychiatric institutions and feigned hallucinations in order to be accepted, but acted normally from then onward. Study was meant to address concerns of

• Stigmatization and marginalization (how fake patients were treated by staff)

• Unrelated problems may be misattributed to diagnosis (example, a behavior that would’ve actually been normal is now considered abnormal because the patient is assumed to have a certain illness)

Categorical Approach to Classification

• Reflects a difference in kind or quality (ex. Apples and oranges)

• Example: Categorizing people as either depressed or not depressed

Dimensional Approach To Classification

• Focuses on the amount of a particular characteristic an object possesses (Ex. Measuring height for two people, but there are different heights)

• Example: People are placed on a continuum from depressed on one side to not depressed on the other.

Reliability

• Consistency of measurements, including diagnostic decisions

• Example: inter-rater reliability refers to agreement of raters about observations

Validity

• What the actual meaning or importance of a measure is

• Asks “valid for what”? Is it measuring what we wanted to measure?

  • We need to ask… how meaningful is it for a desired purpose?

  • Is the SAT valid?

    • (If we’re assessing aptitude, yes, if we are assessing artistic abilities, no)

Etiological Validity

the extent to which a specific diagnosis, classification, or condition shares the same causal factors. It is a foundational concept in medicine and psychology dictating that if patients genuinely have the same underlying disorder, they should share a common origin or etiology.

Predictive Validity

the extent to which a current score on an assessment can accurately predict future treatment and treatment outcomes

Limitations of the DSM-5

• Arbitrary boundary between normal and maladaptive behavior

  • Cutoff points not always empirically justified

  • Reliance on clinicians’ subjective judgment (eg. is this causing significant impairment or not?)

  • Time periods in definitions of diagnoses (eg. How many days is “nearly everyday”)

• Problem of comorbidity, defined as simultaneous appearance of two or more disorders in the same person

  • Of those who meet criteria for one disorder, 56% also meet criteria for at least one other disorder.