Psychotherapists and counselling psychologists may be provided with information regarding patients/clients prior to meeting them for the first time. The information provided may depend upon the setting where the therapists work, and can include a psychiatric diagnosis. This study explores the assumptions, within the literature, around the nature and impact of psychiatric diagnosis on patients/clients and on the clinician. The study then aims to look at ways, if any, that psychiatric diagnosis influences the way psychotherapists and counselling psychologists work. Firstly, the study interviewed four psychotherapists using a semi-structured interview and the data was analysed using an Interpretative Phenomenological Analysis (IPA) as outlined by Smith et al (2009). The findings included that psychiatric diagnosis was an influencing factor as to whether to accept patients for therapy. In addition, a psychiatric diagnosis influenced the way in which they conducted the work, even when they were unaware of it. Secondly, four counselling psychologists were interviewed later, using the same method as outlined above. The findings included that there are specific methods of working designed for different diagnoses. Economic pressures also emerged as a factor that appeared to influence the way psychiatric diagnosis was used. The study went further, by exploring the possibility of utilising IPA to compare the data from each group. The researcher compared the similarities and differences between the two groups based upon the findings obtained from the two separate IPA studies. There appeared to be more similarities than differences between the two groups, the main differences included the importance the psychotherapists placed upon the therapeutic relationship compared to the counselling psychologists and how the counselling psychologists spoke about economic pressures which influenced the way they work with psychiatric diagnosis whereas the psychotherapists did not.