Which condition is characterized by the inability to adapt to stress or maintain stable behavior?

The condition characterized by the inability to adapt to stress or maintain stable behavior is indeed psychosocial disorders. These disorders can negatively impact an individual's emotional, social, and psychological well-being, making it challenging to respond effectively to stressors. People experiencing psychosocial disorders often face difficulties in coping with daily life challenges, which can manifest as anxiety, depression, or unstable interpersonal relationships.

While physical disabilities, chronic diseases, and developmental delays can also affect behavior and stress management, they often do so in different contexts. Physical disabilities might influence a person's ability to perform certain tasks but do not inherently disrupt emotional or psychological stability. Chronic diseases, while they may create continuous stress, are primarily physiological in nature and may not directly correlate with the inability to manage behavior. Developmental delays focus on delays in physical or mental growth, which can lead to challenges but do not primarily center on the inability to adapt to stress. In contrast, psychosocial disorders specifically target the emotional and psychological difficulties in managing stress and behavior, making them the appropriate choice for this question.