Does
Affect Predict Willingness to Take Medication?

Background/Purpose: Affect
is known to have a significant impact on judgment and decision making. The data
supporting this finding, however, are based on subjects’ reactions to written
materials. Our objective was to examine whether the valence and
intensity of a patient’s affective reactions to audible
information influences their willingness to take medication.

Methods: We measured affect in real time as subjects with a chronic
inflammatory rheumatic disease listened to a description of a hypothetical new
medication. Subjects used a joystick to indicate moment-by-moment their
reaction to what they were hearing (+10= Very good, -10= Very bad, and middle
position= 0 being neutral). Patterns of affect reactions were classified using a
cluster analysis approach applied to time series data. After hearing the
presentation, subjects rated their willingness to take the medication on a 7-point
Likert rating scale. We used a multivariate linear regression model to examine the
association between affect patterns and willingness, adjusting for age, numeracy, use of immunosuppressant,
and patient global assessment. An interaction between affect pattern and
ethnicity was included in the model to assess whether ethnicity modified the association
of affect and willingness.

Results: The mean
(SD) age of the study sample (N= 382) was 55 (14) years, 75% were female, 58.4%
identified themselves as being Non-Hispanic White, 23.3% as Non-Hispanic Black,
and 18.3% as Hispanic. Affect reactions were classified into 4 patterns: feel consistently
‘good’ (n= 58), feel consistently close to ‘neutral’ (n= 33), ‘extreme’ positive
reaction to benefits and negative reaction to adverse events (AEs) (n= 109), and
‘average’ (or expected) reaction to benefits and AEs (n= 182). Based on
differences of adjusted least squares means, the patients with good patterns reported
greater willingness than neutral, extreme, or average patterns (t= 2.69, p=
0.007, t= 2.98, p= 0.003, t= 2.37, p= 0.018, respectively). Black patients
reported less willingness than Hispanics or Whites (t= -2.76, p= 0.006, t=
-3.34, p=0.001, respectively). The interaction results revealed that Blacks
were significantly less willing than Hispanics or Whites within the extreme
group only (t= -2.66, p= 0.008, t= -3.36, p=0.001, respectively). Mean
willingness by affect pattern and ethnicity is presented in the Figure below.

Conclusion: Patients who feel consistently good are
most willing to take the new medication compared to groups with other affect
reaction patterns. Black patients, particularly those with an ‘extreme’
reaction pattern, are less willing. These data are consistent with recent
findings demonstrating that both positive and negative affect intensity predict
reluctance to accept risk, and may help explain the increased risk aversion
previously documented in Black patients with rheumatic disease.