Prospective memory in schizophrenia: A meta-analysis of comparative studies

Area of Science:

• Cognitive Neuroscience
• Psychiatry
• Clinical Psychology

Background:

• Prospective memory (PM) impairment is a recognized challenge in schizophrenia.
• This meta-analysis systematically investigates the extent of PM deficits in schizophrenia.

Purpose of the Study:

• To systematically examine and quantify prospective memory (PM) impairment in schizophrenia through a meta-analysis.
• To compare PM performance between individuals with schizophrenia and healthy controls across different PM subtypes.

Main Methods:

• A systematic search of English and Chinese databases (PubMed, PsycINFO, EMBASE, Cochrane, WanFang, etc.) was conducted up to August 14, 2017.
• Included 29 case-control studies involving 2492 participants (1284 schizophrenia patients, 1208 healthy controls).
• Standardized mean differences (SMDs) were calculated using a random-effects model to compare PM performance.

Main Results:

• Schizophrenia patients exhibited significantly poorer performance in overall PM (SMD = -1.125) compared to healthy controls.
• All subtypes of PM, including time-based (SMD = -1.155), event-based (SMD = -1.068), and activity-based (SMD = -0.563), were significantly impaired.
• Subgroup analyses indicated that PM impairment was more severe in older patients, those with higher male predominance, lower education levels, chronic illness, and in eco-valid measurements.

Conclusions:

• The meta-analysis confirms significant impairments in overall prospective memory (PM) and all its subtypes in individuals with schizophrenia.
• Time-based prospective memory appears to be particularly affected.
• Higher negative symptom scores were associated with more severe PM impairment, suggesting a link between symptom severity and cognitive deficits.