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Table 4 Multivariate negative binomial regression model on the willingness to use a CE-drug (n = 2,887)

From: Evaluating the drivers of and obstacles to the willingness to use cognitive enhancement drugs: the influence of drug characteristics, social environment, and personal characteristics

 

IRR a

95% CI b

Drug characteristics

  

Magnitude of enhancement effect (Ref. 5 percent):

  

â–ª a factor of two

1.010

[0.849,1.201]

â–ª a factor of three

1.329**

[1.120,1.577]

Probability of enhancement effect (Ref. 5 percent):

  

â–ª 50 percent

1.287**

[1.081,1.533]

â–ª 100 percent

1.392***

[1.177,1.646]

Severity of side effects (Ref. very light depression):

  

â–ª moderate depression

0.924

[0.781,1.093]

â–ª very strong depression

0.881

[0.746,1.041]

Probability of side effects (Ref. one of 1,000,000 users):

  

â–ª one of 1,000 users

0.955

[0.815,1.119]

â–ª every user

0.634***

[0.533,0.754]

Drug price (Ref. free):

  

â–ª 20 Euros

1.118

[0.955,1.310]

â–ª 100 Euros

0.683***

[0.572,0.815]

Social environment

  

Peer prevalence (Ref. none):

  

â–ª every second

1.287***

[1.089,1.522]

â–ª every one

1.321**

[1.113,1.568]

Social suggestions (Ref. never):

  

â–ª sometimes

0.887

[0.749,1.051]

â–ª very often

1.071

[0.907,1.265]

Social disapproval (Ref. no criticism):

  

â–ª moderate criticism

0.926

[0.788,1.090]

â–ª very strong criticism

0.713***

[0.600,0.846]

Personal characteristics

  

Risk attitudes

1.012

[0.980,1.045]

Academic procrastination

1.112**

[1.034,1.196]

Study motivation

0.897**

[0.839,0.960]

Cognitive test anxiety (CTA)

1.383***

[1.245,1.535]

Competencies

1.048

[0.915,1.199]

Internalized social norms

0.673***

[0.644,0.702]

Prior CE-drug use

2.409***

[1.873,3.097]

Demographic variables

  

Male (Ref. female)

0.949

[0.812,1.110]

Agec

0.969

[0.928,1.012]

Field of study (Ref. sports):

  

â–ª Linguistics & cultural studies

1.260

[0.792,2.004]

â–ª Legal, economic, & social sciences

1.237

[0.763,2.006]

â–ª Mathematics & natural sciences

1.261

[0.797,1.995]

â–ª Human medicine & health

1.272

[0.710,2.279]

â–ª Agriculture, forestry, & nutritional sciences

1.285

[0.716,2.307]

â–ª Engineering

1.845*

[1.089,3.126]

â–ª Arts & science of art

1.669

[0.981,2.839]

Log-pseudolikelihood (full model)

-3566.2

Log-pseudolikelihood (base model)

-3848.1

  1. *p < 0.05, **p < .01, ***p < .001 (Wald tests, robust standard errors).
  2. a Adjusted Incidence Rate Ratios (IRR).
  3. b Confidence Intervals (CI).
  4. c Age was treated as a metric variable (see Table 2 for the 14 measured categories).
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Substance Abuse Treatment, Prevention, and Policy

ISSN: 1747-597X