Dear service user, Thanks for writing to healthcaremagic. I understand your concern about erection problem. It is unfortunate to learn that you have consulted many doctors and undergone tests, which did not help you. You said that you have used sildenafil(Viagra). Let me know whether it helped or not? The common causes of erectile dysfunctions are as follows 1. Diabetes (nerve damage and vessels narrowing) 2. Some medicines like anti depressants and anti psychotics 3. Performance anxiety (the most common reason) 4. Psychiatric disorders (depression, anxiety) 5. Alcohol use (nerve damage and testicular injury) 6. Smoking (vessels narrowing) 7. after some surgical procedures (nerve damage) Let me know whether you achieve and maintain a good quality of erection in sleep, in the early morning, during masturbation but not at the time of coitus? If you are able to achieve and maintain erection in any one of the above mentioned situations than your problem is more likely psychological rather than physical. Rather than consulting neurologist, I recommend you to see a rained psychiatrist well versed with psycho sexual therapies. Discuss this problem with your psychiatrist, who will assist you to find out reason for this problem in your case. There are potentially effective and safe medications as well as behavior therapies for erectile dysfunctions. Psychiatrist will identify the best suited for you after knowing your history. I hope this will help you. If you have any further questions I will be happy to help. Wish you good health.