A child would develop mental illness if one does not get:

The development of mental illness in a child is not solely dependent on the lack or presence of one specific factor. It is usually a combination of various factors including genetic, biological, environmental, and psychological factors.

1. Genetic Factors: If there is a family history of mental health disorders, a child may be more likely to develop a mental illness.

2. Biological Factors: These include brain chemistry, hormone imbalances, and physical illnesses or injuries that may affect the brain.

3. Environmental Factors: These include exposure to violence, abuse, neglect, or other traumatic experiences in early childhood.

4. Psychological Factors: These include a child's personality and how they understand, interpret, and respond to events around them.

5. Lack of Social Support: Children who lack strong, healthy relationships may be more vulnerable to mental health issues.

6. Poor Nutrition: Proper nutrition is essential for brain development. Lack of proper nutrition can lead to mental health issues.

7. Lack of Physical Activity: Regular physical activity is important for mental health. Lack of physical activity can contribute to anxiety and depression.

8. Substance Abuse: Substance abuse can also contribute to mental health disorders.

It's important to note that just because a child is exposed to these risk factors, it does not guarantee they will develop a mental illness. It simply increases the risk. Mental health is complex and unique to each individual.