**Core Concept**
The therapeutic community concept is a psychiatric treatment approach that emphasizes the importance of a supportive and non-hierarchical environment in promoting patient recovery and self-esteem. This approach focuses on the social and interpersonal aspects of mental health, encouraging patients to take an active role in their treatment and to develop a sense of community and belonging.

**Why the Correct Answer is Right**
D. Maxwell Jones is credited with developing the therapeutic community concept in the 1950s and 1960s. He believed that by creating a supportive and non-hierarchical environment, patients could overcome their mental health issues and develop a sense of self-worth and confidence. The therapeutic community approach emphasizes the importance of social and interpersonal factors in mental health, and encourages patients to participate actively in their treatment. This approach is often used in inpatient psychiatric settings and has been shown to be effective in treating a range of mental health conditions.

**Why Each Wrong Option is Incorrect**
**Option A:** Thomas Szasz is known for his critiques of psychiatry and his views on the social and cultural construction of mental illness, but he is not associated with the therapeutic community concept.
**Option B:** R.D. Laing was a Scottish psychiatrist who emphasized the importance of the social and interpersonal aspects of mental health, but he is not credited with developing the therapeutic community concept.
**Option C:** Frieda Fromm-Reichmann was an American psychiatrist who developed the concept of "therapeutic relationship" but not the therapeutic community concept.

**Clinical Pearl / High-Yield Fact**
The therapeutic community approach emphasizes the importance of social and interpersonal factors in mental health, and encourages patients to take an active role in their treatment. This approach can be particularly effective in treating patients with severe mental health conditions, such as schizophrenia.

**Correct Answer:** D. Maxwell Jones.