Final answer:
According to Erikson's psychosocial theory, Edwin's feelings of suspicion and relationship difficulties suggest he did not resolve the Trust vs Mistrust stage, affecting his ability to form intimate relationships without mistrust in adulthood.
Step-by-step explanation:
Edwin did not successfully resolve the Trust vs Mistrust stage of development, which entails the infant's expectations from their caregivers to form a base trust in the world. Since Edwin was neglected in his infancy, his development during this stage likely led to feelings of mistrust. Now, at 31, he is exhibiting traits that suggest he is struggling with the developmental task of intimacy versus isolation. Adults who are cynical and unable to rely on others often find it difficult to form intimate relationships due to residual mistrust from their infancy stage which remains unresolved.
In accordance with Erik Erikson's psychosocial theory, because Edwin did not have responsive caregiving during his infancy, he is now experiencing difficulty forming and maintaining relationships, indicating a failure in the early Trust vs Mistrust stage and resulting in issues related to intimacy in his current developmental stage.