Biases in Diagnosis

Biases in Diagnosis

Anchoring Bias

• Focusing on initial symptoms and overemphasizing that information during diagnosis.

• Basing diagnosis on first impression.

• Friedlander & Stockman (1983): Psychiatrists often didn't change initial diagnosis even with later indications of a serious disorder.

Prestige Effect

• Unwillingness to contradict a diagnosis made by a doctor with more authority.

• Temerlin (1970):

  • Clinical psychologists diagnosed a healthy individual as psychotic after hearing a respected psychologist suggest it.

  • 60% diagnosed psychosis compared to 0% in the control group.

Confirmation Bias

• Preferring evidence that confirms a diagnosis and dismissing disconfirming information.

• Mendel et al (2011):

  • Participants were more likely to make an incorrect final diagnosis (e.g., Alzheimer's) if they reviewed fewer pieces of additional information.

Illusory Correlation

• Perceiving a relationship between two variables when none exists.

• Allows dispositional or situational factors to influence diagnosis (e.g., gender, relationship status).

• Swami (2012): Participants were less likely to diagnose a mental health disorder in a male vignette compared to an identical female vignette.

• Johnstone (1989):

  • More serious diagnoses given to lower-class patients, regardless of symptoms.

Stereotyping

Gender Bias

• Women are more frequently diagnosed with some disorders, and vice versa.

Cultural Bias

• Differences in culture may affect diagnosis.

• Assumes behaviours of the white population are normative.

Socioeconomic Bias

• An individual's socioeconomic status may influence diagnosis.

Premature Closure

• Ending data collection too soon.