Definition, Examples, Types, and How to Write

Key Takeaways

• A case study is a detailed analysis of a single person, group, or event that allows researchers to report in-depth information.
• Case studies are useful when controlled experiments would be difficult, unethical, or impossible to conduct.
• Because case study findings can be subjective, they should be carefully reviewed to avoid bias.

A case study is an in-depth investigation of a person, group, or event used to understand behavior or identify patterns. In psychology, this involves closely examining a subject’s history, experiences, and responses to gain detailed insights that other methods may not capture. While case studies can reveal valuable insights, their findings are often subjective and may not generalize to broader populations.

Verywell / Colleen Tighe

How Case Studies Help and Where They Fall Short

A case study can have its strengths, but that doesn’t mean that it’s right for every situation. Researchers must consider these pros and cons before deciding if this type of study is appropriate for their needs.

Pros

One of the greatest advantages of a case study is that it allows researchers to investigate things that are often difficult or impossible to replicate in a lab. Some other benefits of a case study:

• Allows researchers to capture information on the ‘how,’ ‘what,’ and ‘why’ of something that’s implemented
• Gives researchers the chance to collect information on why one strategy might be chosen over another
• Permits researchers to develop hypotheses that can be explored in experimental research

Cons

On the other hand, a case study can have some drawbacks:

• It cannot necessarily be generalized to the larger population.
• It cannot demonstrate cause and effect.
• It may not be scientifically rigorous.
• It can lead to bias.

Researchers may choose to perform a case study if they want to explore a unique or recently discovered phenomenon. Through their insights, researchers develop additional ideas and study questions that might be explored in future studies.

It’s important to remember that the insights from case studies cannot be used to determine cause-and-effect relationships between variables. However, case studies may be used to develop hypotheses that can then be addressed in experimental research.

Examples of Famous Psychology Case Studies

There have been numerous notable case studies in the history of psychology. Much of Freud’s work and theories were developed through individual case studies. Some great examples of case studies in psychology include:

• Anna O: Anna O. was a pseudonym of a woman named Bertha Pappenheim, a patient of a physician named Josef Breuer. While she was never a patient of Freud’s, Freud and Breuer discussed her case extensively. The woman was experiencing symptoms of a condition that was then known as hysteria, and found that talking about her problems helped relieve her symptoms. Her case played an essential part in the development of talk therapy as an approach to mental health treatment.
• Phineas Gage: Phineas Gage was a railroad employee who experienced a terrible accident in which an explosion sent a metal rod through his skull, damaging important portions of his brain. Gage recovered from his accident but was left with serious changes in both personality and behavior.
• Genie: Genie was a young girl subjected to horrific abuse and isolation. The case study of Genie allowed researchers to study whether language learning was possible after missing critical periods for language development. Her case also served as an example of how scientific research may interfere with treatment and lead to further abuse of vulnerable individuals.

Such cases demonstrate how case research can be used to study phenomena that cannot be replicated in experimental settings.

In Genie’s case, her horrific abuse denied her the opportunity to learn a language at critical points in her development. This is clearly not something researchers could ethically replicate, but conducting a case study on Genie allowed researchers to study phenomena that are otherwise impossible to reproduce.

Different Types of Case Studies

There are a few different types of case studies that psychologists and other researchers might use:

• Collective case studies: These involve studying a group of individuals. Researchers might study a group of people in a certain setting or look at an entire community. For example, psychologists might explore how access to resources in a community has affected the collective mental well-being of those who live there.
• Descriptive case studies: These involve starting with a descriptive theory. The subjects are then observed, and the information gathered is compared to the pre-existing theory.
• Explanatory case studies: These are often used for causal investigations. In other words, researchers are interested in examining factors that may have caused certain events.
• Exploratory case studies: These are sometimes used as a prelude to further, more in-depth research. This allows researchers to gather more information before developing their research questions and hypotheses.
• Instrumental case studies: These occur when the individual or group allows researchers to understand more than what is initially obvious to observers.
• Intrinsic case studies: These are cases in which the researcher has a personal interest in the case. Jean Piaget’s observations of his own children are good examples of how an intrinsic case study can contribute to the development of a psychological theory.

The three main case study types often used are intrinsic, instrumental, and collective. Intrinsic case studies help researchers explore unique cases. Instrumental case studies help look at an individual to learn more about a broader issue. A collective case study can be helpful for looking at several cases simultaneously.

The type of case study that psychology researchers use depends on the unique characteristics of the situation and the case itself.

Where Do You Find Data for a Case Study?

There are a number of different sources and methods that researchers can use to gather information about an individual or group. Six major sources that have been identified by researchers are:

• Archival records: Census records, survey records, and name lists are examples of archival records.
• Direct observation: This strategy involves observing the subject, often in a natural setting. While an individual observer is sometimes used, it is more common to utilize a group of observers.
• Documents: Letters, newspaper articles, administrative records, etc., are the types of documents often used as sources.
• Interviews: Interviews are one of the most important methods for gathering information in case studies. An interview can involve structured survey questions or more open-ended questions.
• Participant observation: When the researcher serves as a participant in events and observes the actions and outcomes, it is called participant observation.
• Physical artifacts: Tools, objects, instruments, and other artifacts are often observed during a direct observation of the subject.

How to Write a Psychology Case Study

If you have been directed to write a case study for a psychology course, be sure to check with your instructor for any specific guidelines you need to follow. If you are writing your case study for a professional publication, check with the publisher for their specific guidelines for submitting a case study.

Here is a general outline of what should be included in a case study.

Section 1: A Case History

This section will have the following structure and content:

Background information: The first section of your paper will present your client’s background. Include factors such as age, gender, work, health status, family mental health history, family and social relationships, drug and alcohol history, life difficulties, goals, and coping skills and weaknesses.

Description of the presenting problem: In the next section of your case study, you will describe the problem or symptoms that the client presented with.

Describe any physical, emotional, or sensory symptoms reported by the client. Thoughts, feelings, and perceptions related to the symptoms should also be noted. Any screening or diagnostic assessments that are used should also be described in detail and all scores reported.

Your diagnosis: Provide your diagnosis and give the appropriate Diagnostic and Statistical Manual code. Explain how you reached your diagnosis, how the client’s symptoms fit the diagnostic criteria for the disorder(s), or any possible difficulties in reaching a diagnosis.

Section 2: Treatment Plan

This portion of the paper will address the chosen treatment for the condition. This might also include the theoretical basis for the chosen treatment or any other evidence that might exist to support why this approach was chosen.

• Cognitive behavioral approach: Explain how a cognitive behavioral therapist would approach treatment. Offer background information on cognitive behavioral therapy and describe the treatment sessions, client response, and outcome of this type of treatment. Make note of any difficulties or successes encountered by your client during treatment.
• Humanistic approach: Describe a humanistic approach that could be used to treat your client, such as client-centered therapy. Provide information on the type of treatment you chose, the client’s reaction to the treatment, and the end result of this approach. Explain why the treatment was successful or unsuccessful.
• Psychoanalytic approach: Describe how a psychoanalytic therapist would view the client’s problem. Provide some background on the psychoanalytic approach and cite relevant references. Explain how psychoanalytic therapy would be used to treat the client, how the client would respond to therapy, and the effectiveness of this treatment approach.
• Pharmacological approach: If treatment primarily involves the use of medications, explain which medications were used and why. Provide background on the effectiveness of these medications and how monotherapy may compare with an approach that combines medications with therapy or other treatments.

This section of a case study should also include information about the treatment goals, process, and outcomes.

Discussion

When you are writing a case study, you should also include a section where you discuss the case study itself, including the strengths and limitations of the study. You should note how the findings of your case study might support previous research. 

In your discussion section, you should also describe some of the implications of your case study. What ideas or findings might require further exploration? How might researchers go about exploring some of these questions in additional studies?

Need More Tips?

Here are a few additional pointers to keep in mind when formatting your case study:

• Never refer to the subject of your case study as “the client.” Instead, use their name or a pseudonym.
• Read examples of case studies to gain an idea about the style and format.
• Remember to use APA format when citing references.

Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

1. Greenhalgh T. Case studies: a guide for researchers, educators, and implementers. BMJ Med. 2025;4(1):e001623. Published 2025 Sep 21. doi:10.1136/bmjmed-2025-001623

2. Charlier P, Deo S. The Anna O. mystery: Hysteria or neuro-tuberculosis? J Neurol Sci. 2017;381:19. doi:10.1016/j.jns.2017.08.006

3. Teles RV. Phineas Gage’s great legacy. Dement Neuropsychol. 2020;14(4):419-421. doi:10.1590/1980-57642020dn14-040013

4. Alpi KM, Evans JJ. Distinguishing case study as a research method from case reports as a publication type. J Med Libr Assoc. 2019;107(1):1-5. doi:10.5195/jmla.2019.615

5. Crowe S, Cresswell K, Robertson A, Huby G, Avery A, Sheikh A. The case study approach. BMC Med Res Methodol. 2011 Jun 27;11:100. doi:10.1186/1471-2288-11-100

6. Yin, Robert K. Case Study Research and Applications: Design and Methods. United States, SAGE Publications, 2017.

By Kendra Cherry, MSEd

Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the “Everything Psychology Book.”

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