Most studies, have found better cognitive functioning in
Psychosis patients with life time or previous illicit drug use as
Compared to psychosis alone, although this has not been consistently shown in all studies
.Furthermore, for cannabis, superior cognitive functioning in the illicit drug using group has been reported in first episode psychosis patients and at 10-year follow-up after onset of psychosis, and replicated by means of functional Magnetic Resonance Imaging (fMRI). Whilst intake of THC has been associated with transient cognitive deficits, mixed results for the intake of stimulants have been reported with both better and worse cognitive performance in non-affective psychosis. It is likely that the effect of both cannabis and stimulants use on cognition in patients with non-affective psychosis is timerelated. Possibly,current illicit drug use, like cannabis, influence cognition more negatively, while previous drug use is a marker of a different pathway to psychosis. The illicit drug using psychotic patients may constitute a subgroup with less cognitive vulnerability; illicit drug use may have a more temporary influence on cognition, generating a short-term cognitive and psychotic breakdown.
Thus, illicit drug use, like cannabis, May create transient deficits in cognition paralleling the period of acute psychosis. To test this hypothesis, it is necessary to examine the change of
Cognitive functioning from the time of an acute psychotic break-through to the stabilization of psychotic symptoms in patients with and without drug use. Furthermore, the drug using group
should be abstinent from illicit drugs in the follow-up period to enable possible cognitive improvement. To accomplish this, only patients with symptoms of acute psychosis admitted to a psychiatric in-patient emergency department were included, and the patients were followed while hospitalized to minimize use of illicit drugs. By4–6 weeks most of the long-term effects of illicit drug use should be minimized, and most psychosis symptoms responding to treatment
. Follow-up was therefore set to time of discharge from the acute ward or after 6 weeks at the latest, if not discharged earlier. This was allowed for both a naturalistic prognostic design and
a reduction of variability in regard to time to follow-up. Furthermore, a brief neuro psychological screening instrument with alternative forms; the Repeatable Battery for the Assessment of Neuropsychological Status(RBANS), was used to minimize potential practice effects. Earlier longitudinal studies on cognitive functioning have usually not addressed the issue of practice effects sufficiently. Latent Growth Curve modeling was chosen to
examine cognitive trajectories from baseline to follow-up in order to minimize the effect of missing data, controlling for the baseline level in cognitive functioning and varying test–retest intervals. The aim of the present study was to compare cognitive changes in non-affective psychosis patients with illicit drug use to cognitive changes in non-affective psychosis patients with no illicit drug use after an acute psychotic episode. It was hypothesized that the drug
group would show more improvement in cognitive functioning from time of admission to a psychiatric emergency ward to time of discharge from the acute ward or after 6 weeks at the latest