All of the following are symptoms of thought disorder except __________.

Thought disorder is characterized by a disorganized or dysfunctional thinking process that can manifest in a variety of symptoms. Delusions, hallucinations, and disorganized thinking are all indicative of a thought disorder, as they reflect a deviation from typical cognitive functioning.

Delusions are strong beliefs that are not grounded in reality, which can severely affect one's thoughts and perceptions. Hallucinations involve perceiving things that are not present, such as hearing voices; this also disrupts normal thought processes. Disorganized thinking is directly related to thought disorder, influencing how individuals articulate their thoughts and connect ideas.

Happiness, however, does not fit within the framework of thought disorder symptoms. It is a positive emotional state and does not indicate any cognitive dysfunction or disturbance in thought processes. Therefore, it stands out as not being a symptom of a thought disorder. Understanding these distinctions is crucial in identifying and diagnosing thought disorders accurately.