Which court case is notable for defining a therapist's responsibility when working with suicidal clients?

The court case most notable for defining a therapist's responsibility when working with suicidal clients is Tarasoff v. California Board of Regents. This landmark case established the legal obligation for mental health professionals to warn individuals who may be in danger due to a client's threat of harm or suicidal ideation. The ruling emphasized the duty to protect potential victims, which extends beyond confidentiality in certain circumstances, particularly when a client poses a significant risk to themselves or others.

In contrast, the other cases listed do not specifically focus on the responsibilities towards suicidal clients. Cobbs v. Grants primarily deals with informed consent and a patient's right to be involved in treatment decisions. Ewing v. Goldstein involves considerations of duty to care but does not directly address the obligation to warn in the context of suicidal clients. Bella v. Greenson, while it may involve similar ethical concerns, is not the pivotal case like Tarasoff that is widely referenced in discussions regarding therapist responsibilities toward suicidal clients. Thus, Tarasoff is the definitive case that established the legal precedent in this area.