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Overall, cocaine and methamphetamine users share similar neuropsychological profiles. However, cocaine appears to be more associated with working memory impairments, which are typically frontally mediated, while methamphetamine appears to be more associated with memory impairments that are linked with temporal and parietal lobe dysfunction.

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Objective Heroin dependent individuals appear to have significant deficits in attention which can be assessed using digit span forward (DSF) or the continuous performance test (CPT). The current meta-analysis examined differences between DSF and CPT results in studies of heroin dependent participants. Data selection Two researchers independently searched nine databases (e.g., PsycINFO, Pubmed, ProceedingsFirst), extracted required data, and calculated effect sizes. Inclusion criteria identified studies that had (a) compared heroin-dependent groups to healthy controls and (b) matched groups on either age, education, or IQ (at least 2 out of 3). Studies were excluded if participants were reported to have Axis I diagnoses (other than heroin dependence) or comorbidities known to impact neuropsychological functioning. Ten articles were coded and analyzed for the current study. Data synthesis When examined together, DSF and CPT evidenced a moderate and statistically significant effect size estimate (g = 0.614, p = .002). Subgroup analysis did not reveal statistically significant differences between the two groups (Q-Between = 0.228, p = 0.633). The effect size for DSF was g = 0.535 (p = 0.001) and for CPT was g = 0.774 (p = 0.104). The heterogeneity of DSF was in the moderate range, I2 = 71.291%, p = 0.002 while the heterogeneity of CPT was in the large range I2 = 97.863%, p = 0.001. Conclusion Heroin dependent individuals appear to demonstrate similarly poor performance on DSF and CPT. Assuming that both tests measure the same construct, both appear to be sensitive to the effect of Heroin on attention.

Objective Late-life depression (LLD) has been associated with cognitive impairments in domains such as memory, processing speed, and executive functions (e.g., initiation). However, it is unclear whether or not LLD is associated with language fluency difficulties that are often seen in some forms of dementia. Broadly, letter fluency is often observed to be associated with frontal deficits while category fluency is thought to be linked to temporal lobe dysfunction. Both tests are commonly used to assess language in older adults. The current meta-analysis examined potential differences between letter and category fluency in LLD and the robustness of previous findings in this population. Data Selection Investigators searched eight databases including PubMed and PsycINFO using terms such as “neuropsychol*,” “late-life,” and “depression.” Studies were excluded if participants were diagnosed with severe mental illness, neurological or other medical conditions that impact neurocognition. Data Synthesis Independent coders extracted data from 27 studies (k = 10 letter fluency, k = 17 semantic fluency). The effect size for semantic fluency was g = 0.64 (p < 0.001) with significant heterogeneity I² = 73.53% (Q = 60.45, df = 16, p < 0.001). The effect size for letter fluency was g = 0.49 (p < 0.001) also with significant heterogeneity I² = 52.08% (Q = 18.78, df = 9, p < 0.027). Conclusions Depressed individuals exhibited poorer performance on both category and letter fluency when compared to controls. This may indicate that depressed elderly individuals have difficulty with initiating verbal responses regardless of whether these responses rely on semantic networks or executive control.