features
Violence in schizophrenia is heterogeneous in its
origin and manifestations. It may be directly related to
clinical symptoms. One hypothesis links elevated rates
of violence among people with mental illness to a small
set of delusional psychotic symptoms-so called threat/
control-override (TCO) symptoms (Link et al. 1998,
Link & Stueve 1994). These symptoms are elicited by
questions like "dominated by forces beyond you",
"thoughts put into your head", and "people who wished
you harm".
However, a large study suggested that although
delusions can precipitate violence in individual cases,
they do not increase the overall risk of violence
(Appelbaum et al. 2000). Delusional motivation of
violence appears to be rare (Junginger et al. 1998).
Command hallucinations to harm others may increase
risk of violence, although the level of compliance with
such commands varies (Junginger 1995, Junginger &
McGuire 2001). In general, positive symptoms of
schizophrenia are associated with an increased risk of
violence, whereas negative symptoms show the opposite
relationship (Swanson et al. 2006). Finally, there is
consistent evidence linking impaired insight to violence
(Alia-Klein et al. 2007, Antonius 2005, Ekinci & Ekinci
2012, Lera et al. 2012). This effect may be indirect,
mediated through the reduced adherence to treatment
that is associated with poor insight (Alia-Klein et al.
2007, Coldham et al. 2002) (Czobor et al. 2013).
Contrary to the belief of many clinicians, much of
the violence committed by schizophrenia patients does
not seem so be directly related to psychotic symptoms.
Recent evidence suggests that violence among adults
with schizophrenia may follow at least two distinct
pathways-one associated with premorbid conditions,
including antisocial conduct, and another associated
with the acute psychopathology of schizophrenia
(Swanson et al. 2008b). In that study, adherence with
antipsychotic medications was associated with
significantly reduced violence only in the group without
a history of conduct problems. In the conduct problems
group, violence remained higher and did not
significantly differ between patients who were adherent
with medications and those who were not (Swanson et
al. 2008b). Since the outcome did not depend on
whether these patients actually did take the medication,
we can infer that a history of conduct disorder is
associated with reduced effectiveness of antipsychotics.
This hypothesis remains to be tested.
These findings are consistent with previous observations
indicating that only about 20% of assaults on a
psychiatric ward was directly attributable to psychotic
symptoms like delusions or hallucinations (Nolan et al.
2003). The other assaults appeared to be due to confusion,
impulsiveness, or comorbid antisocial personality
disorder/psychopathy. Thus, there are multiple pathways
to violence in schizophrenia, and this etiological
heterogeneity has implications for treatment (Volavka &
Citrome 2011).