Final answer:
The described symptoms suggest that the college student has Obsessive-Compulsive Disorder (OCD), with common comorbidities including anxiety and depression. Treatment usually consists of cognitive-behavioral therapy and medications.
Step-by-step explanation:
The 18-year-old male college student is likely suffering from Obsessive-Compulsive Disorder (OCD), which is a common psychiatric disorder characterized by obsessive thoughts and compulsive actions such as excessive washing. The student's fear of bacteria and belief that he can "feel" them on his skin, despite acknowledging the excessive nature of his behavior, points to obsessive thinking and the compulsive action of over-cleaning as an attempt to alleviate his anxiety.
Common comorbidities with OCD include anxiety disorders, depression, and tourette syndrome. Treatment typically involves a combination of cognitive-behavioral therapy (CBT), particularly Exposure and Response Prevention (ERP), and medication like Selective Serotonin Reuptake Inhibitors (SSRIs). A psychiatrist or clinical psychologist can offer a tailored treatment approach after a thorough evaluation.