It can be argued that an individual’s subjective experience and beliefs
about a substance are important. Motives and expectancies regarding the use of
alcohol and drugs are often that they are going to modify a cognitive state or
help them cope with a particular situation. However, there are growing concerns
in the U.S.A. and in the U.K. regarding individuals who experience psychosis and
concurrently use substances. Correctly diagnosing individuals with dual
presentation is said to be difficult, engagement in treatment is problematic, and
medication adherence and prognosis poor. In this paper a cognitive-developmental
model is proposed. I suggest that for individuals who experience psychosis and
also use drugs or alcohol, the ability to identify the relationship between the
substance use and the psychotic illness in terms of a case formulation/conceptualization
would provide a good starting point for developing strategies and interventions
that are most likely to succeed in treatment. Such an approach would explicitly
address key cognitions. Unless the dysfunctional substance-related beliefs are
addressed, adherence to medication and engagement with treatment services will
be hindered and the possibility of relapsing to problematic substance use and
acute psychosis remains. A cognitive treatment component, to target these beliefs,
based on the cognitive model of substance misuse and the motivational
interviewing approach will also be briefly outlined.