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Systematic Reviews in the Health Sciences

Subject Headings Versus Keywords

Before beginning a search in PsycInfo or CINAHL, it is helpful to identify a combination of both subject headings and general keywords that you will use to find articles.

Subject Headings: This is the standardized vocabulary ("controlled vocabulary") that the database indexers use to help users find and identify articles of interest. Subject Headings describe the key topics covered in the article.

Keywords: Keywords describe the simple, everyday words ("natural language") you would use when describing a health topic.

When searching PsycInfo or CINAHL, I recommend using a combination of natural language and subject headings.

Finding Subject Terms & Keywords

Both PsycInfo and CINAHL have a sub-database that allows you to identify standard subject headings that describe a concept that you want to research. In PsycInfo, this database is called the Thesaurus, and in CINAHL, it is a Subject Headings database.

For example, you can use the PsycInfo Thesaurus to find terms related to schizophrenia:


The thesaurus is showing us that psychosis is a broader term for schizophrenia. You may want to incorporate this term into your search strategy.

You can use hints provided by the citations themselves to identify additional terms to add to your search. For example, if you are looking for articles on vocational rehabilitation, you may find an alternative term. Note that the citation below lists "supported employment" as a subject heading. You may want to incorporate this phrase into your search.

An Example of a Search

Health Sciences Librarian

Kate Silfen's picture
Kate Silfen
Mugar Memorial Library