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Comorbid Personality Disorders and Substance
Use Disorders of Mentally 111 Homicide
Offenders: A Structured Clinical Study on
Dual and Triple Diagnoses
by Anu Putkonen, Irma Kotilainen, Christian C. Joyed, and Jari Tiihonen
Several studies have demonstrated that persons suffering
from MMD are at increased risk for community violence,
other violent offenses, and homicide, particularly if they
have coexisting alcoholism or SUD (Swanson et al. 1990;
Eronen et al. 1996i>; Hodgins et al. 1996a; Tiihonen et al.
1996; RSsfinen et al. 1998; Brennan et al. 2000). Moran et
al. (2003) were die first to demonstrate the independent
association between premorbid ICD-10 PD and number
of physical assaults during a 2-year followup among community-dwelling patients with psychotic disorders
(UK700 study data, n = 670). However, the authors could
not examine whether comorbid PD increased the risk of
serious assaults in psychosis, because neither the seriousness nor the frequency of assaults was recorded. The literature provides no direct evidence of an association
between comorbid personality disorders and severe violence among psychotic individuals. Data from high- and
low-risk subgroups are important, as SUDs are common
among persons with MMD (47% lifetime prevalence in
the United States), compared to the general population
(13.2%, Regier et al. 1990), while only a few of the dually
diagnosed (MMD + SUD) persons commit homicide
(Eronen et al. 1996fc).
Among nonpsychotic persons, antisocial personality
disorder (APD) has a strong association with homicide
(Eronen et al. 1996a). Comorbidity of APD with other
psychiatric disorders is common; in the Epidemiological
Catchment Area (ECA) study, as much as 84 percent of
U.S. individuals with APD also had alcohol use disorder,
and a powerful association between active APD and
schizophrenia and mania was reported (Regier et al.
1990). The lifetime prevalence of APD in the U.S. general
population was estimated to be 4.5 percent among males
and 0.8 percent among females. Because nonpsychotic
individuals with APD are characterized by poor compliance with medical treatments, including medication
Abstract
Comorbid substance use disorders (SUDs) increase
the risk of homicide by persons with major mental
disorders (MMDs). However, there are no published
data from clinical interviews or lifetime objective
documents on the prevalence of lifetime personality
disorder (PD) or SUD among a comprehensive sample of mentally ill homicide offenders. Therefore, a
nationally representative sample of men with MMD
(n = 90) who had committed or attempted homicide
was assessed using the research version of the
Structured Clinical Interview for DSM-IV Axis I
and Axis II Disorders. Lifetime documents, records,
and questionnaires from persons who knew the subjects since childhood were used. Seventy-eight percent of the mentally ill homicide offenders were diagnosed with schizophrenia, 17 percent with
schizoaffective disorder, and 5 percent with other
psychosis. A lifetime SUD was detected in 74 percent
and alcohol use disorder in 72 percent PD accounted
for 51 percent, in 47 percent as antisocial personality
disorder (APD). All subjects diagnosed with PD had
SUD. Only 25 percent of the subjects had neither
SUD nor PD. Among persons with dual diagnoses
(MMD and SUD), about two-thirds had PD or APD.
These results indicated that there were two-thirds
major diagnostic categories of psychotic homicide
offenders: about one-half had triple diagnosis (APD
+ SUD + MMD), one-quarter had "pure" dual diagnosis (SUD + MMD), and one-quarter had "pure"
MMD. The fourth possible category, "APD + MMD
but no SUD," was not found. The prevention of
severe violence by persons with MMD necessitates
effective treatments for those with dual diagnosis
who also have a history of APD.
Keywords: Major mental disorders, schizophrenia, antisocial personality disorder, substance abuse,
homicide, violence.
Schizophrenia Bulletin, 30(l):59-72,2004.
Send reprint requests to Dr. A. Putkonen, Department of Forensic
Psychiatry, University of Kuopio, Niuvanniemi Hospital, FIN-70240
Kuopio, Finland; e-mail: [email protected].
59
Schizophrenia Bulletin, Vol. 30, No. 1, 2004
A. Putkonen et al.
(Black et al. 1988), psychotherapy (Woody et al. 1985),
and integrated substance abuse and psychiatric treatment programs for dually diagnosed patients (Robins et
al. 1991), the same may apply to persons with MMD
and a history of APD. Thus, the role of APD could also
be of great interest when early prevention of violent
crimes and treatment of violent psychotic patients are
considered.
SUD Among Mentally 111 Homicide
Offenders
The studies on comprehensive samples of mentally ill
homicide offenders (table 1; Lindqvist 1986; Gottlieb et
al. 1987; Gabrielsen et al. 1992; Eronen 1995; Eronen et
al. 1996fc; Erb et al. 2001) reported lower prevalence of
alcoholism or SUD among homicide offenders with psychotic disorders (8-44%) than among nonpsychotic homicide offenders (61%, Gottlieb et al. 1987).
The low prevalence of APD (8-14%) and SUD
(8-44%) among nationally representative samples of male
homicide offenders with MMD in the existing literature is
not in accordance with the replicated findings that SUD is
more common among persons with schizophrenia (47%
lifetime prevalence in the United States), compared to the
general population (13.2%; Regier et al. 1990), and that
SUD is associated with increased risk for homicidal
behavior among individuals with schizophrenia. However,
these reports were made on the basis of file documents
and without patient interviews. Such studies are likely to
underrecord comorbid SUD and APD, because SUD is
substantially underdiagnosed in psychiatric care settings
(Drake and Mueser 2000; Hansen et al. 2000) and prisons
(Abram and Teplin 1991) and PD is traditionally not
determined or documented in patients who meet the criteria of MMD (Surtees and Kendell 1979). Later, the multiaxial system of DSM classification (APA 1994) made it
more likely that clinicians would diagnose both lifetime
MMD and PD within the same person.
It is difficult to study clinically the association of
APD, MMD, and homicide. The optimal study design, a
prospective cohort study, should be very large to achieve
sufficient statistical power because of the rarity of both
homicides and MMD in the general population. Persons
with APD tend to gather together, or to be selected, in
populations or facilities with a very high prevalence of
APD and SUD (Abram and Teplin 1991). Therefore, not
even comparative data of lifetime APD among all persons
with MMD in communities are available. In most Western
countries, it is also impossible to obtain objective historical documents for individuals from large populations.
Without such documents, childhood conduct disorder
symptoms, which are needed for the DSM-IV diagnosis of
APD, are underdiagnosed and the resulting prevalence
remains low. In many Western countries, prison populations include homicide offenders with MMD (Taylor and
Gunn 1984; C6t6 and Hodgins 1990). Therefore, the studies of representative high-security hospital populations or
prison populations in such countries are not nationally
representative samples of psychotic homicide offenders in
these countries. Possibly the best available way would be
a structured clinical study of a nationally representative
APD Among Mentally 111 Homicide
Offenders
Results from the only study concerning the prevalence of
comorbid APD among a nationally representative sample
of mentally ill homicide offenders by Erb et al. (2001)
indicated that only 8 percent of all male homicide offenders with schizophrenia in West Germany from 1955 to
1964 (n = 284), and 14 percent of male homicide offenders with schizophrenia in Hessen from 1992 to 1996 (n =
29), met the criteria of DSM-III for APD on the basis of
hospital documents and crime registers (table 1). A
smaller Canadian study compared homicide offenders and
nonhomicide offenders who were incarcerated in Quebec
penitentiaries (C6t6 and Hodgins 1992). Among 11 homicide offenders with schizophrenia in that study, 64 percent
had APD and 73 percent had alcohol use disorder. Among
36 persons with affective disorders (2 with bipolar disorder, 5 with atypical bipolar disorder, and 29 with major
depression), the prevalence of APD was 65 to 100 percent
and of SUD 60 to 100 percent in each diagnostic group.
However, the sample set did not include mentally ill
homicide offenders who had been "not guilty of homicide
by reason of insanity," and the number of offenders in
each group was small (n - 2-29).
PD Among Mentally 111 Homicide
Offenders
Two studies have reported the prevalence of mentally ill
homicide offenders with any existing comorbid PD diagnosis in their examination reports for juridical court
(Lindqvist 1986; Putkonen et al. 2001) and one study the
prevalence of PD among a U.K. security hospital population (Taylor et al. 1998; table 1). Lindqvist found that
9 percent of mentally ill homicide offenders of both
sexes (n = 34) in Northern Sweden from 1970 to 1981,
and Putkonen et al. found that 32 percent of female
homicide offenders with MMD in Finland (n = 34) were
diagnosed with PD. Taylor et al. (1998) studied the
records of the patients in three U.K. security hospitals
and diagnosed 231 homicide offenders with ICD-10
psychosis and 78 having "psychosis with independent
PD" (25%).
60
Schizophrenia homicide
offenders and attempters in
Hessen (1992-1996)
124 female homicide offenders
examined for court in Finland
1980-1992
DSM-III-R diagnoses were made
on the basis of forensic psychiatric
examination reports, hospital
records, crime registers, and yearly
assessments for court.
29 (25 males + 4
females) with
schizophrenia
All schizophrenia homicide
offenders and attempters in
Federal Republic of Germany
1955-1964
Erbetal. (2001)
Eronen(1995)
DSM-III-R diagnoses were made
on the basis of forensic psychiatric
examination reports, hospital
records, crime registers, and yearly
assessments for court.
284 (232 males + 52
females) with
schizophrenia
All 1,740 patients resident in
the 3 special hospitals in the
United Kingdom during the first
half of 1993
Taylor etal. (1998)
18 female
schizophrenia patients
309 with psychosis
gender distribution not
specified
93 (86 males + 7
females) with
schizophrenia
1,428 homicide offenders
examined for court in Finland
during 12 yrs (75% of all)
Eronenet al. (1996ft)
Diagnoses of forensic psychiatric
examination reports were collected.
ICD-10 diagnoses were made on
the basis of hospital records.
Criminal records were available on
two-thirds of the sample.
DShA-lll-R diagnoses were made
on the basis of forensic psychiatric
examination reports.
Diagnoses of psychiatric
examination reports were collected.
Substance abuse2 of (A) psychotic
and (B) nonpsychotic offenders.
58 with psychosis (42
males + 16 females),
16 of whom had
schizophrenia
251 of 263 homicide offenders
investigated for court in
Copenhagen during 1959-1983
Diagnoses of forensic psychiatric
examination reports were collected.
Gottlieb etal. (1987)
Gabrielsen et al. (1992)
34 with "mental
disease, mainly males"
Method
All 64 homicide offenders (60
males + 4 females) in Northern
Sweden during 1970-1981
Subjects of the study
Undqvist(1986)
Authors (yr)
Number, gender, and
diagnostic
distribution of
mentally III homicide
offenders
APD
—
—
25%
—
—
14%
8%
—
—
—
—
9%
(6% +
SUD)
PD
SUD
33% 1
38%,1
31 % 3
—
Males
44%, 1
females
43% 1
males 40%
females
12%
A: 33%,
32%
Prevalence of
Table 1. The prevalence of PD, APD, and SUD In previous studies of mentally III persons with homicidal behavior, calculated on the basis
of published data
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Schizophrenia Bulletin, Vol. 30, No. 1, 2004
A. Putkonen et al.
s
sample of psychotic homicide offenders in a country
where the clearing rate of homicides is high, all homicide
offenders having psychiatric symptoms are examined, and
objective lifetime documents are available. To date, there
have been no such studies concerning the prevalence of
comorbid APD and SUD among representative samples of
homicide offenders with MMD. Because file-based studies may underestimate possible dual and triple diagnoses,
die aim of the present study was to determine whether the
prevalence of APD and SUD in a clinical interview study,
verified with detailed documents, differs from that in document studies.
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In Finland, MMD has, in practice, been considered such a
severe disorder as to diminish the ability of an individual
to control his or her violent behavior. Therefore, violent
offenders are investigated by senior psychiatrists if any
psychiatric symptoms have been detected in criminal
investigations, hearings, documents, or examinations in
prison by medical staff, or if the homicide offender or his
or her lawyer asked for investigation. About 70 percent of
all homicide offenders undergo a detailed forensic psychiatric examination that includes physical examinations,
brain CT or fMRI study, EEG, laboratory tests, structured
psychological tests, and usually structured diagnostic
interviews (Eronen et al. 1996a) during a period of 4 to 8
weeks, usually in a psychiatric or forensic psychiatric
hospital. Mentally ill homicide offenders and mose who
attempted homicide are not convicted in juridical court.
However, the forensic Psychiatric Board (of the Ministry
of Social and Health Affairs) commits such individuals to
one of two state psychiatric hospitals, on the basis of the
examination report and collateral documents. This same
board eventually permits their discharge. Only in very
exceptional cases are homicide offenders with a pretrial
MMD diagnosis incarcerated in prisons (Putkonen et al.
2001). The examination reports include data that are
obtained by court order from physicians and hospitals,
schools, social welfare offices, the military, prisons, and
crime registers, in addition to questionnaires completed
by parents, siblings, teachers, and employees.
On 1 March 1998 there were 99 persons in the
Niuvanniemi (psychiatric state) Hospital who were diagnosed as suffering from MMD during their homicidal act.
Two of them were female. Ninety-three persons were
willing to be interviewed between March and May of
1998. Three persons were excluded: one female and two
males who did not obtain an MMD diagnosis. For the
final analysis, 90 males were evaluated by the Structured
Clinical Interview for DSM-IV Axis I Disorders
(SCID-I). The information was insufficient in two cases
concerning the assessment of SUD. Five persons could
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62
Mentally 111 Homicide Offenders
Schizophrenia Bulletin, Vol. 30, No. 1, 2004
not be assessed with the Structured Clinical Interview
for DSM-IV Axis H Disorders (SCID-II) because of a
lack of confirmed information on their behavior before
the age of 15. One of them had already been excluded
from the SUD assessment. All but two (both Asian
males) were Caucasians. Of all the participants, 65
(72%) had committed one or more homicides and 25
(28%) had attempted to kill someone. The mean age of
the participants was 43.6 years (range 21-73 years,
standard deviation [SD] 11.5). The participants were
committed to the hospital between 1948 and 1997
(mean 1989, SD 9.60), 35 of them (39%) during the last
3 years. The mean duration of treatment was 8.7 years
(range 1-50 years, SD 9.60).
DSM-IV Axis I and Axis II diagnoses were assessed
with the SCID Research Version (First et al. 1996a,
1996£>) by two forensic psychiatrists. According to the
SCID protocol, all available information was used.
Information given by a participant during the interview
was subsequently verified through other sources. Both
medical and psychiatric data, and forensic psychiatric
examination reports, were studied. Because of the limited
ability of most patients to use the self-report personality
questionnaire, we assessed all items as needed. The interviews lasted between 2 and 8 hours. To test the interrater
reliability, 15 percent of the participants were studied by
both of the interviewers. The concordance rates between
the raters were 1.00 concerning MMD and PD, and 0.86
concerning SUD.
Offenders with PD could have been discharged from
the hospital at either a later or an earlier stage of treatment, when compared to those with pure psychotic disorders. Therefore, the PD data were also compared by the
X2 test with those of the patients having a longer duration
of treatment. The prevalence of PD and SUD between
homicide offenders and homicide attempters was compared as well.
The prevalence and comorbidity of PD, SUD, and
MMD diagnoses were calculated for the entire sample and
for the main MMD groups. The co-occurrence of PD and
SUD for each MMD group was compared with that of
other patients with the x 2 test- A p value lower than 0.05
was considered statistically significant. SPSS 8.0 for
Windows was used for statistical analyses.
and comorbidity of PD and SUD subtypes in the main
MMD groups are shown in table 2.
Seventy-eight percent of the male homicide offenders
were diagnosed with schizophrenia, 17 percent with
schizoaffective psychosis, and 5 percent with other psychoses. Fifty-one percent of the patients additionally
received one or more lifetime PD diagnoses, including 47
percent with APD. Many patients fulfilled the criteria for
several PDs (figure 2).
An SUD diagnosis was obtained for 74 percent of the
88 offenders for whom SUD was assessed (figure 3).
Seventy-two percent (n = 63) had alcohol abuse, and 64
percent (n - 56) had alcohol dependence. Other substance
than alcohol abuse was diagnosed in 36 percent {n - 32)
of the cases, and other substance dependence in 33 percent (n = 29). Thus, 89 percent of the alcohol abusers and
91 percent of the other substance abusers were also
dependent on those substances.
Seventy-five percent of the offenders obtained more
than one psychiatric diagnosis (figure 4). All participants
with PD also had SUD, but only half of those with no PD
had SUD. The prevalence of PD and APD among offenders
with dual disorders was 66 percent and 61 percent, respectively. The prevalence of PDs (table 2) was significantly
higher among die group with schizophrenia (n = 65, x 2 =
4.44, df= \,p = 0.035) than among the remaining subjects
(n = 20). The group with schizoaffective disorder (n = 15)
had a significantly higher prevalence of SUD than the
remaining subjects {n = 73, x 2 = 14.86, df=l,p = 0.0001).
There was no substantial difference between tie persons who were admitted to the hospital during the last 3
years and those who had been in the hospital for more
than 3 years, concerning the prevalence of PD (x 2 = 0.10,
df= 1, p = 0.7573, n = 85) or SUD (X2 = 1.13, df= I, p =
0.287, n = 88). Nor was there a difference between those
who committed a homicide and those who attempted to
commit a homicide, concerning the prevalence of PD (x 2
= 1.26, df= l,p = 0.263, n = 85) or SUD (x 2 = 1.86, df =
\,p = 0.173, n = 88).
Discussion
These results demonstrated that there are three distinct
diagnostic categories of psychotic persons who kill or try
to kill others (figure 4). A triple diagnosis (MMD + APD
+ SUD), die largest category, included about half (47%)
of the mentally ill homicide offenders. A "pure" dual
diagnosis (MMD + SUD) was found among a quarter
(24%), and only a quarter (25%) had "pure" MMD. The
fourth possible category, "APD and MMD but no SUD,"
was not found among this nationally representative sample of men with MMD who had killed or tried to kill
someone.
Results
The distribution and comorbidity of different MMDs,
PDs, and SUDs are shown in figures 1, 2, and 3, respectively. Figure 4 illustrates the comorbidity of substance
use and personality disorders and three diagnostic categories. For comparison, previous studies on mentally ill
homicidal offenders are listed in table 1. The prevalence
63
A. Putkonen et al.
Schizophrenia Bulletin, Vol. 30, No. 1, 2004
Figure 1. Psychotic disorders among mentally III persons with homicidal behavior (n = 90)
Other psychosis
5%
Schizoaffective
disorder
17%
Schizophrenia
78%
of the codisorders and provide important new data from
severe violence of psychotic persons.
SUDs, particularly alcohol use disorders, are known
to increase the risk of homicide (Eronen et al. 1996a)
among persons with MMD. However, the relationship
between APD and severe violence of persons with MMD
has been unclear. Structured interview studies have
demonstrated that lifetime APD is common in prison populations, both among nonpsychotic criminal offenders
(49%-61%) and among randomly selected males with
MMD convicted of various crimes in Quebec penitentiaries (63%, n - 38) and in Chicago Cook County Jail
(81%, n = 65) (C6t£ and Hodgins 1990; Abram and Teplin
1991). However, prison populations are biased and
exclude offenders found not guilty by reason of insanity.
Hodgins et al. (19966) hypothesized that it is the syndrome of stable antisocial behavior rather than substance
abuse that is related to offending among persons with
schizophrenia. The present study demonstrated that in
severe violence of individuals with MMD, lifetime SUD
is diagnosed in 74 percent, and APD in 47 percent.
However, neither APD nor SUD alone but the combina-
To our knowledge, our study was the first that
reported a high prevalence of APD (47%, figure 2), SUD
(74%), and alcohol use disorders (72%, figure 3) among a
nationally representative sample of psychotic homicide
offenders. The prevalence of SUD (alcoholism) was about
1.6-fold among mentally ill homicide offenders, compared to the rate among persons with schizophrenia in the
ECA study (Regier et al. 1990). Previously, it seemed that
only 8 to 14 percent of homicide offenders with schizophrenia had a history of APD (Erb et al. 2001) and that
the prevalence of alcoholism was lower among psychotic
homicide offenders (8%-44%, table 1) than among persons with MMD in the general population. However, the
previous studies on nationally representative samples of
homicide offenders were made from examination reports
for court and hospital documents. A substantial underdiagnosing of SUD by psychiatrists has been demonstrated
(Hansen et al. 2000). Also, according to diagnostic hierarchy, lifetime PD has traditionally not been diagnosed in
the presence of MMD (Surtees and Kendell 1979). Thus,
a structured study with clinical interviews and objective
lifetime documentation could result in higher prevalence
64
Schizophrenia Bulletin, Vol. 30, No. 1, 2004
Mentally 111 Homicide Offenders
Figure 2. Comorbldlty of PDs among mentally III persons with homicidal behavior (n = 85)1
^APDonly34%
No PD 49%
APD = 47%
BPD= 11%
OPD =
APD + BPD 3%
avoidant PD (5.8%)
obsessive-compulsive PD (3.5%)
passive-aggressive (3.5%)
depressive (2.3%)
narcissistic (2.3%)
histrionic (1.2%)
schizoid (1.2%)
APD + BPD + OPD 6%
BPDonly 1%
APD + OPD 5%
OPD only 2%
Note.—APD = antisocial personality disorder; AUD - alcohol use disorder; BPD = borderline personality disorder; OPD = other personality disorder; PD = personality disorder.
1
Five patients could not be assessed.
SUD (alcoholism)" may be rare but in any case is not
associated with homicidal behavior.
tion of both lifetime APD and SUD (alcohol use disorder)
was the most "dangerous" category among persons with
MMD. The prevalence of this triple diagnosis (APD +
SUD + MMD) was nearly two times greater than the
prevalence of pure dual diagnosis (SUD + MMD) or pure
MMD. Also, among all persons with dual diagnoses
(MMD + SUD), those with an additional history of APD
had a particularly high risk for severe violence and
accounted for nearly two-thirds (61%) of the homicidal
acts of this group. However, APD was not found among
53 percent of homicide offenders.
Our result that APD without SUD was not found
among mentally ill homicide offenders could suggest that
all subjects having MMD and APD in communities would
also have alcoholism. However, a structured interview
study by Hodgins et al. (19966) demonstrated that among
74 male schizophrenia patients consecutively discharged
from a security hospital and two psychiatric hospitals in
Canada, 27 percent (n = 20) had APD. The prevalence of
alcohol use disorder was only 45 percent and of other
SUD 70 percent. Thus, 55 percent did not have alcohol
use disorder. (The prevalence of alcohol use disorder
among non-APD schizophrenia patients was 20%.) We
suggest that the combination "MMD and APD but no
APD Among Persons With MMD in Community and
Treatment Settings. We have not found any community
study that demonstrates the prevalence of APD among a
nationally representative sample of persons with MMD.
Such data would be needed to compare the prevalence of
APD in homicidal and nonhomicidal men suffering from
MMD. The prevalence of DSM-III APD in structured
interview studies among persons with MMD in different
treatment settings varied between 1 percent and 81 percent and was highest in prisons (Abram and Teplin 1991).
In a recent report from U.K. 700 study data (Moran et al.
2003), the prevalence of ICD-10 dissocial PD was 6 percent among the 670 outpatients with MMD in London.
Persons with a primary diagnosis of alcoholism had not
been included. The prevalence of DSM-IV APD in the
present study was 8-fold compared to this rate.
Methodological Considerations. Research of violent
behavior is complicated by many practical issues. Most
violent offenses are mild and not registered in police
records, and in most countries a large proportion of
65
Schizophrenia Bulletin, Vol. 30, No. 1, 2004
A. Putkonen et al.
Figure 3. Comorbldlty of AUDs and SUDs among mentally III persons with homicidal behavior (n = 88)1
NoSUD
26%
AUD only
38%
Other SUD only
2%
Other SUD+AUD
34%
Note.—AUD = alcohol use disorder; SUD - substance use disorder.
1
Two patients could not be assessed.
crimes remain unsolved (International Criminal Police
Organization 1998). Moreover, in many countries only a
small proportion of all homicide offenders undergo forensic psychiatric examination. Such shortcomings could be
circumvented by studying exclusively serious violent
crimes, such as homicide, in countries where the elucidation rate is high and most violent offenders are thoroughly
investigated. We believe that our sample was representative of insane Finnish males with homicidal behavior
because of the high clearing rate of homicides during the
years of the sample (95%-98%), the comprehensive pretrial practice of diagnosing MMD among violent offenders, and the practice of sending all homicide offenders
with pretrial MMD diagnoses to state psychiatric hospitals. Selective discharge was excluded by comparing the
patients who had been in the hospital less than 3 years
with those who came over 3 years ago.
In general, many individuals tend to understate their
behavioral problems and their substance use, even when
interviewed. Crime registers do not provide information
on most of the items that are included in the diagnostic
criteria of DSM-IV APD, such as symptoms of childhood
conduct disorder. This emphasizes the importance of
obtaining other objective data dating back to childhood.
The prevalence of SUD and PD in the present study represents the rate of DSM-IV diagnoses made on the basis of
interviews, data on several years of hospital observation,
lifetime registers, records, and questionnaires from parents, teachers, and others who knew the patient. However,
it is possible that the prevalence of PD and SUD could be
even higher.
Nolan et al. (1999) reported that comorbid psychopathy as assessed by Hare's criteria was more common
(19%) among violent than among nonviolent hospitalized
patients with schizophrenia (n = 51), but they did not
study clinical diagnoses. Hare's criteria for psychopathy
are a way to predict future violence. Because the aim of
the present study was to obtain data on the epidemiology
of severe violence among persons with MMD and persons
with dual diagnoses, we did not study psychopathy but
assessed DSM-IV diagnoses with the latest research version of the SCID. Although many persons with high psychopathy scores have APD, all persons with APD do not
have psychopathy.
Diagnostic instruments derived from the DSM-IV
Axis II usually have good test-retest and interrater relia-
66
Mentally 111 Homicide Offenders
Schizophrenia Bulletin, Vol. 30, No. 1, 2004
Figure 4. Comorbidity of PDs and SUDs among mentally ill persons with homicidal behavior, three
diagnostic categories (n = 84)1
Triple diagnosis
(MMD+SUD+PD)
51%
"Pure" dual diagnosis
(MMD+SUD)
24%
Note.—MMD « major mental disorder; PD = personality disorder; SUD = substance use disorder.
1
Six patients could not be assessed.
bility, although their validity in assessing the constructs
has been questioned (Westen 1997). Studies that compared different rating instruments (Perry 1992) at the
beginning of the 1990s showed good agreement for people with any PD. However, the average capacity of different instruments to similarly categorize patients by Axis II
diagnosis was low, partly because of a lack of construct
validity of DSM-IV personality disorders. Discriminative
validity was, however, highest for APD and borderline PD
(Hyler et al. 1992; Westen 1997), which have been successfully studied with these instruments. Studies on different diagnostic instruments showed that a PD diagnosis
could not be made simply on the basis of direct questions.
Clinical observation and information on interpersonal
interactions over time were always also needed. This
emphasizes the importance of clinical examination and
may partly explain the different results from file-based
and interview studies. In the ECA study, APD was the
only DSM-III—R Axis II disorder investigated, independently of Axis I disorders, because it fulfills the criteria of
a clinical syndrome (e.g., the symptoms are highly intercorrelated, APD has a genetic component [Lyons et al.
1995], and it is found in every society). Because APD was
the main target of interest in our study, we considered the
SCID to be the best research instrument available for it.
Criminal history does not necessarily mean that a
person has both conditions of APD diagnosis (i.e., at least
two symptoms of childhood conduct disorder and at least
three symptoms of adult antisocial behavior). In selected
populations, such as prison populations, the SCID—II may
not provide high discrimination power. However, in populations where APD is less common and the information on
childhood conduct disorder and adult antisocial behavior
is available, the SCID for DSM-IV Axis II disorders is
useful and gives valuable information about the etiology
of violent behavior. A person who has behaved violently
since childhood may fulfill the above-mentioned DSM-IV
criteria of APD. However, all persons with APD are not
violent, and one instance of violent behavior like homicide does not indicate a diagnosis of APD. Only one of
the seven other symptoms of APD, "the pervasive pattern
of disregard for and violation of the rights of others," is
irritability or aggressivity, although three symptoms are
needed for the diagnosis. Likewise, only 47 percent of
psychotic homicide offenders in the present study were
diagnosed with APD.
67
Schizophrenia Bulletin, Vol. 30, No. 1, 2004
A. Putkonen et al.
Table 2. The prevalence of PD and SUD in the main groups of major mental disorders among homicidal
patients
Schizophrenia
(n = 70)
Schizoaffective Disorder
(n = 15]I
Other Psychoses
(n == 5)
Total
n
%
n
%
n
%
n
%
PD
PD
NoPD
PD could not be assessed
APD
BPD
OPD
APD + BPD
APD + OPD
BPD + OPD
37
28
5
35
8
9
7
7
4
56.9
43.1
7.1
52.2
12.1
13.6
10.8
10.6
6.2
5
10
0
4
1
4
1
2
1
33.3
66.7
0
26.7
6.7
26.7
6.7
14.3
6.7
1
4
0
1
0
0
0
0
0
20.0
80.0
0
20.0
0
0
0
0
0
43
42
5
40
9
13
8
9
5
50.6
49.4
5.6
47.0
10.6
15.3
9.4
10.5
5.9
SUD
SUD
No SUD
SUD could not be assessed
AUD
OSUD
AUD, no OSUD
OSUD, no AUD
AUD + OSUD
50
18
2
49
29
20
1
28
73.5
26.5
2.9
72.1
42.6
29.4
1.5
41.2
12
3
0
11
3
9
1
2
80.0
20.0
0
73.3
20.0
60.0
6.7
13.3
3
2
0
3
0
3
0
0
60.0
40.0
0
60.0
0
60.0
0
0
65
23
2
63
32
32
2
30
73.9
26.1
2.3
71.6
36.4
36.4
2.3
34.1
PD and SUD
PD, no SUD
SUD, no PD
No SUD, no PD
PD or SUD not assessed
37
0
12
16
5
56.9
0
18.5
22.9
7.1
5
0
7
3
0
33.3
0
46.7
20.0
0
1
0
2
2
0
20.0
0
40.0
40.0
0
43
0
21
21
5
50.6
0
24.7
24.7
5.6
Note.—APD - antisocial personality disorder; AUD - alcohol use disorder; BPD = borderline personality disorder; OPD - other personality disorder; OSUD = other substance use disorder; PD = personality disorder; SUD - substance use disorder.
In the McArthur Study (Steadman et al. 1998) no significant difference was found between the prevalence of
violence by discharged patients (n = 51) and persons living in the same neighborhoods, a result that seems to contradict several previous and subsequent studies among
persons with schizophrenia. However, less than a fifth of
the patients followed in that study were diagnosed with
schizophrenia (17.2%). And, as Steadman et al. (1998)
reported, followed-up patients were less likely to have a
documented history of violence than patients lost to followup. Furthermore, 44 percent of the patients with schizophrenia refused to participate in the study, which is a
high proportion that is likely to include most antisocial
personalities with schizophrenia.
tries. The population in Finland, with over 5 million
inhabitants, is considered to be socially and racially
homogeneous. Organized crime, illegal drug abuse, and
gang violence have been less common in Finland than in
most other Western countries. The homicide rate, however, has been higher in Finland than in most European
countries (2.14-3.03 per 100,000 population), but it is still
only one-third of the rate found in the United States
(7.9-9.8 per 100,000 population) (Eronen et al. 1997).
About 77 percent of all homicide offenders in Finland
were heavily intoxicated by alcohol during the homicide
(Virkkunen 1974). There are, unfortunately, no large epidemiological studies on the prevalence of APD and SUD
in the general population, or among persons with schizophrenia in Finland. In a large birth-cohort study (n =
11,017), males with coexisting schizophrenia and alcoholism (n = 11) were 25.2 times more likely to commit
violent crimes than mentally healthy men, and 36 percent
had already committed violent crimes (Rasanen et al.
1998), but no one had committed homicide. However,
National Considerations. There are no priori reasons to
believe that substantial national differences exist in the
prevalence of APD and SUD in Western countries.
However, the possibility may not be totally ruled out until
structured clinical studies are performed in other coun-
68
Mentally Dl Homicide Offenders
Schizophrenia Bulletin, Vol. 30, No. 1, 2004
even non-SUD males with schizophrenia had a 3.6 times
higher risk for violent crimes than males without mental
disorders. None of the women with schizophrenia (n = 25)
had committed any crimes. Low socioeconomic status
(SES) did not increase the risk of violence among males
with schizophrenia, as boys with schizophrenia from
high-SES homes had a higher risk for violent crimes than
boys with schizophrenia from low-SES homes (Tiihonen
et al. 1997). Seven percent of all male violent offenders of
the cohort were diagnosed as psychotic by the age of 26.
this underdiagnosed subgroup of mentally ill persons with
a history of APD and SUD, and the subsequent lack of
effective treatments, is likely to be associated with their
poor outcome and increased risk for severe violence. For
instance, the insufficient response of violent offenders to
traditional psychiatric treatments, which are usually targeted to psychotic symptoms and only sometimes to dual
disorders, may be a consequence of the high prevalence of
APD among violent offenders.
In the treatment of violent offenders with MMD, distinguishing the three categories (persons with triple diagnoses, persons with pure dual diagnoses, and persons with
pure MMD) is of clinical importance because the risk factors for violence and the treatment needs of each group
are likely to be different Antisocial peers, disadvantaged
neighborhoods (Silver et al. 1999), and easy access to
alcohol and some other psychoactive drugs may be particularly detrimental for patients with a triple diagnosis
(APD + SUD + MMD). Early detection of psychotic
symptoms and administration of novel antipsychotic medication in the early phase of the MMD may decrease substance abuse (Drake and Mueser 2000), symptoms of
APD (Benedetti et al. 1998), and violent behavior. The
effects of integrated treatments for dually diagnosed persons might be improved if the persons with pure dual disorders and those with a history of APD were treated in
separate settings. Further research is needed to demonstrate whether the prognosis of different groups of violent
offenders with MMD can be improved by specific integrated, multidisciplinary, long-term treatment programs,
according to the needs of persons with dual and triple
diagnoses. The prevention of severe violence by mentally
ill persons necessitates that effective treatments be created
for those with dual diagnoses who also have a history of
APD.
Treatment A dual diagnosis (i.e., the combination of
MMD and SUD) is associated with poor treatment outcome (Drake and Mueser 2000), increased psychotic
symptoms (Negrete et al. 1986; Drake et al. 1989), medication noncompliance (Drake et al. 1989), hostile and
threatening behavior (Drake et al. 1989), depression, suicidal behavior (Bartels et al. 1992), and psychosocial
problems such as homelessness (Drake et al. 1991).
Persons with dual diagnoses have an increased vulnerability toward negative outcomes, which include violence,
legal problems, and incarceration, and they are less capable of being helped by traditional psychiatric or substance
abuse treatments. Alcohol and most other psychoactive
drugs increase the risk for violent behavior by pharmacologically disinhibiting aggressive impulses (Virkkunen
1974), which can increase conflict and volatility in social
relations, thus exacerbating symptoms of perceived threat
and hostility (particularly in persons with active psychoses), substituting for or interfering with prescribed
psychotropic medications that might otherwise control
high-risk symptoms, increasing economic stress and survival demands, and, finally, exposing the user to criminal
affiliations and surroundings. The violent acts of persons
with APD and SUD may result from certain psychotic
symptoms (Link et al. 1992), although the violence is
more likely to reflect interactions between several different factors (e.g., personality traits, history of violent
behavior, substance abuse [Taylor et al. 1998]) and/or
originate from childhood antisocial behavior (Arsenault et
al. 2000; Tengstrom et al. 2001).
There are promising data of integrated treatments for
dually diagnosed persons (Ridgely et al. 1990; Drake et
al. 1998; Drake and Mueser 2000), but there is not much
evidence on specific treatments of persons with triple
diagnoses. APD is associated with poor compliance, not
only for traditional treatments but also for integrated treatments for dually disordered persons (Robins et al. 1991).
However, we have not found any controlled studies of
specific treatments for persons with triple diagnoses
(MMD + SUD + APD), and, therefore, we do not know if
they cannot be treated with the methods currently available. The lack of data on the specific treatment needs of
Conclusions
Several conclusions can be drawn from this study. First,
there are three different diagnostic categories of persons
with MMD who kill or try to kill others. About one-half
had a triple diagnosis (MMD + APD + SUD), one-quarter
had a pure dual diagnosis (MMD + SUD), and one-quarter had pure MMD. The fourth possible category, "APD
and MMD but no SUD," was not found.
Second, APD (DSM-FV) is an important predictor of
severe violence of psychotic persons, but only when
comorbid with SUD.
Third, among persons with dual diagnoses (MMD +
SUD), those with a history of APD are a particular risk
group for severe violence. People with triple diagnosis
accounted for nearly two-thirds (61%) of the homicidal
acts of this group.
69
Schizophrenia Bulletin, Vol. 30, No. 1, 2004
A. Putkonen ct al.
Fourth, lifetime SUD, and particularly alcoholism, is
an even more important risk factor for severe violence
among psychotic males than the previous literature has
demonstrated. Among mentally ill homicide offenders, 74
percent had SUD and 72 percent had an alcohol use disorder.
Fifth, the prevention of severe violence of persons
with MMD necessitates that effective treatments be created for persons with triple diagnoses (MMD + SUD +
APD).
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Jbckel, D. Homicide and schizophrenia: Maybe treatment
does have a preventive effect. Criminal Behaviour and
Mental Health, 11:6-26, 2001.
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72
Acknowledgments
The authors thank Ms. Aija Ra"sSnen and Mrs. Tarja
Mehtonen for secretarial assistance.
The Authors
Anu Putkonen, M.D., is Forensic Psychiatrist; Irma
Kotilainen, M.D., is Forensic Psychiatrist; and Christian C.
Joyal, Ph.D., is Visiting Researcher, Department of Forensic
Psychiatry, University of Kuopio and Niuvanniemi Hospital,
Kuopio, Finland. Jari Tiihonen, M.D., Ph.D., is Professor and
Chairman, Department of Forensic Psychiatry, University of
Kuopio and Niuvanniemi Hospital; Senior Lecturer,
Department of Psychiatry, University of Helsinki, Helsinki,
Finland; and Consultant, Department of Clinical Physiology,
Kuopio University Hospital, Kuopio, Finland.