Neuropsychological functioning and age-related changes in schizophrenia and/or cocaine dependence

Although little is known about the combined effects of Schizophrenia (SZ) and Substance Use Dependence (SUD) in neurocognitive functioning, the current literature points out that performance depends on the specific cognitive domains, the age of individuals and the type of substance of abuse. Our aim is to elucidate, in a sample with SZ and/or cocaine dependent individuals in remission for more than 4 months, their performance in attention, verbal memory and speed of processing, taking into account the possible effect of both age and duration of SUD. The total sample consisted of 95 male patients, aged 20 to 60 years, divided in three groups: one group with SZ and cocaine dependence (SZ +), another group with SZ without cocaine dependence (SZ −) and a third group with cocaine dependence without psychiatric comorbidity (COC). Our results show that those SZ + who were abstinent for more than four months did not differ from their SZ − counterparts in the neuropsychological functioning. Both SZ groups performed significantly worse than the COC group. A negative impact of age on the neuropsychological performance was found in the SZ + group, suggesting additive later cognitive deficits in SZ + patients due to the long-term brain damage of SUD.

► The COC group showed better neurocognitive functioning than both SZ + and SZ − groups.
► The SZ + individuals with 4 months of abstinence did not differ from their SZ − counterparts.
► Cognitive impairment in SZ + is negative related to age, suggesting lasting long-term effects of SUD.