It's important to keep careful records of the finalized search strategy that you create, along with the results that that strategy yields in each database you search. After you run your finalized search strategy in each database, you must save all the results in a reference management system for later screening. Keep records of how many sources are produced from each search, as you will need to complete a flow chart of your sources and information later in the screening process.
Helpful Resources to Get You Started:
The Importance of Using Both Keyword and Indexed Terms
Another option alongside Boolean Searching is Proximity Searching. From U Melbourne:
"Proximity searching allows better control of the relevance of concepts by adjusting their proximity to one another. If the concepts occur close together in a sentence or paragraph, the topics are more likely to be relevant than if they are widely separated.
Most database platforms offer proximity operators to specify word order and separation. Check the help system of the database you are using and look for proximity to find information on how to apply it correctly.
Replace # with the maximum number of words to occur between the two concepts."
Proximity Searches in Common Databases and Platforms
bipolar W2 disorder
depression N2 anxiety
Different databases have different syntax -- "rules" and usages for search fields, search punctuation, and search proximity indicators. The tool linked below provides some useful information.