What is open access?
Open access is the provision of scholarly articles for free, to be accessed by anyone. There are a couple of categories of open access articles.
Gold: These articles are published in online journals - either the entire journal is open access OR a particular article has been provided as open access in an otherwise restricted journal (the journal is usually pay-per-view or subscribe to access articles).
Green: These articles are provided through digital repositories, mostly run by learning institutions, like universities. Other repositories are based on a theme or topic. The author submits their work for uploading to the repository. The article may be in a pre-published format, or final draft, rather than in the published form.
Articles that have been published and peer reviewed are known as white literature and articles that are yet to be peer reviewed are known as grey literature. Articles from Green sources may be grey literature, that is they may not yet be peer reviewed.
Are open access articles good quality?
It depends. Sometimes sweeping statements are made about the unreliability of open access articles, however, some of the top ranking journals on any given topic may be open access. Additionally, items that are retrieved through digital repositories may be exact replicas of a peer-reviewed published article.
It is good to be aware that some journals and articles are better than others, and scrutinise information that is found accordingly.
Open access journals
The Directory of Open Access Journals (DOAJ) is a good place to start looking at what open access journals are available. Below are a few examples of open access journals on the topic of alcohol and other drugs (AOD) and mental health (MH).
On the topic of AOD
Substance abuse treatment, prevention and policy (UK) (Free full text from PubMed Central)
Harm reduction journal (UK) (Free full text from PubMed Central)
CrossCurrents: The Journal of Addiction and Mental Health (Canada)
On the topic of MH
Counselling, Psychotherapy and Health (cphJournal) (Australia)
Clinical Practice and Epidemiology in Mental Health (UK) (Free full text from PubMed Central)
BMC Psychology (UK)
This is just a small snippet of what is available out there, and this doesn't include the digital repositories of universities and other organisations, which are growing everyday. If you've come across a useful open access site be sure to share it here in the comments.