\
PERGAMON
Personality and Individual Di}erences 16 "0888# 090Ð097
Nicotine\ ca}eine\ alcohol and schizotypy
Abigail L[ Larrison\ Kevin A[ Briand\ Anne B[ Sereno
Center for Molecular and Behavioral Neuroscience\ Rutgers^ State University of New Jersey\ Newark\ NJ 96091\ USA
Received 16 April 0887
Abstract
Schizophrenics are known to be heavy smokers[ It has also been reported that in a normal population
smoking is associated with higher scores on scales of schizotypy[ The present study investigated the use of
nicotine as related to scores on a positive symptoms scale of schizotypy[ 174 undergraduate students at
Rutgers University completed the Rust Inventory of Schizotypal Cognitions "RISC# in addition to a
questionnaire regarding smoking habits\ ca}eine and alcohol use[ Results showed a relationship between
schizotypy and the use nicotine\ and also the use of ca}eine and alcohol[ Use of the stimulants ca}eine and
nicotine were associated with higher RISC scores\ whereas low stimulant users "nonsmoking\ low ca}eine
users# scored the lowest on the administered scale of schizotypy[ The e}ects of both stimulants were not
additive\ as demonstrated by a signi_cant interaction between nicotine and ca}eine use[ The use of alcohol\
a CNS depressant\ showed the opposite relationship\ with increasing alcohol use associated with lower RISC
scores[ The relationship between schizotypy and increased use of stimulants and decreased use of depressants
is discussed[ Þ 0888 Elsevier Science Ltd[ All rights reserved[
Keywords] Alcohol^ Ca}eine^ Nicotine^ Schizotypy^ Schizophrenia^ Smoking
0[ Introduction
Previous studies have demonstrated a relationship between smoking and high scores on scales
of schizotypy "Eysenck\ 0879^ Golding\ Harpur\ + Brent!Smith\ 0872^ Seltzer + Oechsli\ 0874^
Gilbert\ 0877^ Pritchard\ 0880^ Gilbert + Gilbert\ 0884^ Williams et al[\ 0885#[ The explanation for
these _ndings have ranged from the suggestion that smoking may contribute to such schizophrenic
traits "Holden\ Mooney\ + Newman\ 0883^ Williams et al[\ 0885#\ to the opposite hypothesis that
smoking may help alleviate symptoms associated with schizophrenia "Adler\ Ho}er\ Gri.th\
Waldo\ + Freedman\ 0881^ Adler\ Ho}er\ Wiser\ + Freedman\ 0882^ deLeon\ 0885#[
Corresponding author[ Tel[] ¦0!862!242!0979\ ext[ 2142^ fax] ¦0!862!242!0429[
9080!7758:88:, ! see front matter Þ 0888 Elsevier Science Ltd[ All rights reserved[
PII] S 9 0 8 0 ! 7 7 5 8 " 8 7 # 9 9 1 0 6 ! 6
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A[L[ Larrison et al[ : Personality and Individual Differences 16 "0888# 090Ð097
Far less has been reported regarding schizotypy and other types of drug use[ Personality scales\
such as the MMPI\ have demonstrated strong relationships between drug use and personality
factors[ For example\ {sensation seeking| has been shown to be associated with an increased general
drug use "Andrucci\ Archer\ Pancoast\ + Gordon\ 0878#[ Thus increased smoking in schizotypy
may be due to an increase in overall drug use[ In addition\ the mesocorticolimbic dopamine system
has been implicated in the rewarding properties of drugs "for review see Koob\ Robledo\ Markou\
+ Caine\ 0882#[ Since the primary transmitter implicated in schizophrenia is dopamine\ the
possibility exists that persons high in schizotypal traits are simply more prone to engage in addictive
behaviors[ Therefore\ in addition to questions regarding smoking and nicotine use\ subjects were
asked questions regarding the use of the licit drugs alcohol and ca}eine[
Schizotypal personalities can be clustered into positive trait and negative trait schizotypy "Ken!
dler et al[\ 0880#[ Here we utilize a scale of mainly positive symptoms[ It has been suggested that
smoking may be related speci_cally to negative symptoms and not the positive symptoms of
schizophrenia "Lohr + Flynn\ 0881#[ However\ there is no direct relationship known between the
positive and negative symptoms of schizophrenia and the positive and negative symptoms of
schizotypy[ Furthermore\ the use of a positive symptoms subscale of schizotypy may be preferred\
since these symptoms have been shown to be better predictors of later diagnoses of schizophrenia
"Chapman + Chapman\ 0876^ Chapman\ Chapman\ Kwapil\ Eckblad\ + Zinser\ 0883#[ The
following experiment is a _rst investigation of the relationship between patterns of drug taking
behavior and schizotypy as measured by the Rust Inventory of Schizotypal Cognitions "RISC#[
1[ Methods
1[0[ Subjects
Students enrolled in an Introduction to Psychology course at Rutgers\ the State University of
New Jersey\ Newark Campus were administered questionnaires\ including a scale of schizotypy[
1[1[ Scale
The Rust Inventory of Schizotypal Cognition "RISC# was used as our measure of schizotypy[
This commercially available\ standardized scale was designed to measure positive symptoms
schizotypy\ in particular magical thinking[ It is a 15!item scale\ in a forced choice format "strongly
agree\ agree\ disagree\ strongly disagree#[ It has been shown to have no ethnic and no gender biases
"Rust\ 0877#\ to have good internal and external reliability and validity "Rust\ 0877# and to
correlate well with other positive symptoms scales "Balogh\ Merritt\ + Steuerwald\ 0880#[
1[2[ Questionnaire
A questionnaire of personal information and legal drug habits was given to each subject along
with the RISC[ Personal information included date of birth and ethnicity\ gender information was
not obtained\ but should be considered for future studies since smoking patterns and rates of
schizophrenia di}er across gender[ For drug use information subjects were required to report] if
A[L[ Larrison et al[ : Personality and Individual Differences 16 "0888# 090Ð097
092
they were ever a smoker\ the amount they smoked\ the brand they smoked\ whether their parents
and:or other relatives smoked and exposure to second hand smoke[ In addition\ a choice scale was
included regarding alcohol and ca}eine use[ The choice scale simply required the subject to circle
the number of ca}einated or alcoholic drinks they consumed per day or week\ respectively[ All
information was collected con_dentially[
1[2[0[ Nicotine
Persons who reported smoking every day for at least six months were categorized as smokers[
Subjects reporting never smoking\ or having tried cigarettes once or twice were categorized as
nonsmokers[ Also\ subjects who reported having been smokers "see previous de_nition#\ but had
quit were included as smokers[ These subjects accounted for less than 0) of our population[
1[2[1[ Caffeine
Subjects were coded as low ca}eine users if they reported having 9Ð1 ca}einated beverages per
day\ as moderate ca}eine users if they reported having 2Ð4 ca}einated beverages per day and as
high ca}eine users if they reported having more than six ca}einated beverages per day[
1[2[2[ Alcohol
Alcohol use was reported so that subjects were coded as low\ moderate or high users of alcohol[
Low use was considered 9Ð1 drinks per week\ moderate as 2Ð4 per week and high as more than
six[ The moderate and high groups were collapsed to two levels due to the small number of subjects
reporting over six alcoholic beverages per week[ Therefore the _nal alcohol group contained a low
"9Ð1 alcoholic beverages per week# and a high alcohol group "2¦ per week#[
1[3[ Design and analysis
Data was submitted to a 1×1×2 between factor analysis of variance "ANOVA#[ Between
subject factors were SMOKE "smoker\ nonsmoker#\ ALCOHOL "low\ high# and CAFFEINE
"low\ moderate\ high#[
2[ Results
2[0[ Sample
Ninety!seven smokers and 077 nonsmokers with a mean age of 11[6 and 10[5\ respectively\
completed the questionnaires and were included in the study[ Seventeen subjects were excluded
due to incomplete questionnaires[
2[1[ Scale
The distribution of scores on the RISC in our population of 174 students was comparable to
those values reported in the scale|s standardization "Rust\ 0878#[ The mean and median of our
sample was 24[85 and 25[99\ respectively\ with a standard deviation of 7[70[ Scores ranged from a
093
A[L[ Larrison et al[ : Personality and Individual Differences 16 "0888# 090Ð097
Table 0
The overall 1 "SMOKE#×1 "ALCOHOL#×2 "CAF!
FEINE# ANOVA table
Source
Smoke "S#
Alcohol "A#
Ca}eine "C#
S×A
S×C
A×C
S×A×C
Residual
a
df
F!value
p!value
0
0
1
0
1
1
1
162
5[21
7[86
9[15
0[54
1[85
1[97
0[70
9[90a
9[99a
9[66
9[19
9[94a
9[02
9[06
Signi_cant[
minimum of 7 and maximum of 54\ giving an e}ective range of 46[ Kurtosis was 9[52 and skewness
−9[06[
2[2[ Schizotypy and drug use
2[2[0[ Stimulants
There was a signi_cant main e}ect of smoking "SMOKE#\ on RISC score\ where smokers showed
increased scores on the RISC compared to nonsmokers F"0\ 162#5[21\ p9[90 "Table 0#[ More
importantly\ there was a signi_cant interaction between the two stimulants reported\ SMOKE and
CAFFEINE\ on RISC score F"1\ 162#1[85\ p9[94 "see Fig[ 0#[ Low stimulant use\ i[e[ non!
smokers with low ca}eine intake\ showed the lowest RISC scores[ Smoking was associated with
increased RISC scores but only in the low ca}eine group[ Nonsmokers with moderate or high
ca}eine use scored in the same range as smokers[ Thus\ the use of both nicotine and ca}eine did
not additively increase RISC scores[
2[2[1[ Depressants
There was a signi_cant main e}ect of ALCOHOL on RISC with increasing alcohol use associated
with decreasing scores on the RISC\ F"0\ 162#7[86\ p³9[994 "Fig[ 1#[ There were no signi_cant
interactions involving ALCOHOL[
3[ Discussion
Our study reports a signi_cantly increased score on the RISC for smokers[ This is consistent
with previous _ndings of an increase of schizotypal traits in smokers "Eysenck\ 0879^ Golding et
al[\ 0872^ Seltzer et al[\ 0874^ Gilbert\ 0877^ Pritchard\ 0880^ Gilbert et al[\ 0884^ Williams et al[\
0885#[ In addition\ we demonstrate that higher ca}eine consumption is associated with higher
A[L[ Larrison et al[ : Personality and Individual Differences 16 "0888# 090Ð097
094
Fig[ 0[ An interaction plot between smoking and ca}eine use with RISC score as the dependent variable "F"1\ 162#2[9
p9[94#[ This interaction e}ect\ as can be seen here\ is due to the greater e}ect of smoking on RISC only in the low
ca}eine use group[ Where moderate and high ca}eine users scored equally high on the RISC whether or not they smoke[
Fig[ 1[ An interaction plot between smoking and alcohol use with RISC score as the dependent variable[ As is seen here
there is no interaction between smoking and alcohol but there is a main e}ect of alcohol use[ Alcohol use being associated
with decreased scores on the RISC "F"0\ 162#8[9 p³9[994#[
095
A[L[ Larrison et al[ : Personality and Individual Differences 16 "0888# 090Ð097
Table 1
Data adapted from Schneier and Siris "0876#[ By separating patterns of drug use by schizophrenics into depressants and
stimulants a striking pattern appears[ Schizophrenics do not show general increased drug dependence\ but selectively
use CNS stimulants
Depressants
Alcohol
Signi_cantly more
Signi_cantly less
Alterman\ Erdlen and Murphy "0870#
Bernadt and Murray "0875#
Crowley\ Chesluk\ Dilts and Hart "0863#
O|Farrell\ Connors and Upper "0872#
Crowley et al[ "0863#
McLellan and Druley "0866#
Tsuang\ Simpson and Kronfol "0871#
Whitlock and Lowry "0856#
Crowley et al[ "0863#
Hekimian and Gershon "0857#
Tsuang et al[ "0871#
Sedatives
Narcotics
Stimulants
Amphetamine
Ca}eine
Stimulants NS
Tobacco
Breakey\ Goodell\ Lorenz and McHugh "0863#
McLellan and Druley "0866#
Rockwell and Ostwald "0857#
Prosser and Pickens "0868#
Richard\ Liskow and Perry "0874#
Hughes\ Hatsukami\ Mitchell and Dahlgren "0875#
Kirch\ Shelton and Gori "0874#
O|Farrell et al[ "0872#
RISC scores in nonsmokers\ whereas higher alcohol use was associated with lower scores on the
RISC[
The _ndings we report here for schizotypy are consistent with the patterns of drug use associated
with schizophrenia[ In a comprehensive review of the literature on drug taking patterns in schizo!
phrenia\ Schneier and Siris "0876# list only one report of increased use of a CNS depressant and
ten reports of signi_cantly decreased use of depressants by schizophrenics[ Stimulant use showed
the opposite pattern[ Eight reports found signi_cantly increased stimulant use by schizophrenics\
while not a single report found decreased stimulant use "see Table 1#[
Ours and others| _ndings of a general increase in stimulant taking behavior\ and a decrease in
use of depressants in schizotypals and schizophrenics suggests\ that stimulants may hold properties
which appeal to persons scoring high on schizotypy\ while depressants may be avoided due to
unpleasant e}ects[ The _nding that the use of one stimulant "either nicotine or ca}eine# was
associated with higher RISC scores and that these stimulants did not act additively\ emphasizes
the interactive function of pharmacological agents[ Future studies examining the relationship
between nicotine and schizotypy should consider the subjects| use of additional stimulants and
depressants[
Although it is important to recognize that these are correlative data and do not show causation\
A[L[ Larrison et al[ : Personality and Individual Differences 16 "0888# 090Ð097
096
ongoing research suggests nicotine may alleviate symptoms and attentional de_cits associated with
schizophrenia[ Studies in schizophrenics demonstrate nicotine is able to eliminate speci_c sensory
gating de_cits "Adler et al[\ 0881\ 0882# and reduce problems with smooth pursuit eye movements
"Olincy\ Ross\ Young\ Roath\ + Freedman\ 0887#[ Smoking by schizophrenics is associated with
reduced distress during the prodromal phase of the illness "Hamera\ Schneider\ + Keviney\ 0884#
and nicotine withdrawal is associated with an exacerbation of existing schizophrenic symptoms
"see Dalack + Meador!Woodru}\ 0885#[ Future research examining the e}ects of nicotine and
other stimulants\ on attentional de_cits seen in schizotypy might better address the question of
causation[
Acknowledgements
The authors would like to thank Dr[ Walter Pritchard and an anonymous reviewer for helpful
comments on the manuscript[ Requests for reprints should be addressed to A[L[L[\ Center for
Molecular and Behavioral Neuroscience\ Rutgers University\ 086 University Avenue\ Newark\ NJ
96091[ This work was supported in part by] McDonnell!Pew\ N[A[R[S[A[D[\ Scottish Rite and
Busch Biomedical grants[
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