I am a 28-year-old man. Four years ago, when I was a student and still a virgin, I stupidly got drunk one night and two women I knew decided to have their way with me. It was a nasty, painful, humiliating "initiation" - far from the kind of first sexual experience I'd fantasised about. I still have nightmares about it and have been unable to perform sexually with anyone since. I know I should have handled myself better that night, but I can't seem to get past it.

When a person is intoxicated, he lacks the capacity to give consent to sex. It seems you experienced a serious sexual assault and like many victims of this kind of crime, you are blaming yourself for something that was perpetrated by others. You probably avoided reporting it or even telling friends or family for fear of being ridiculed or held responsible - our society often refuses to recognise sexual coercion of men by women. Because you knew these women, you are holding yourself accountable; but they should not have betrayed your trust. The trauma caused by such an experience is no less severe because these women were acquaintances rather than strangers; some survivors of similar ordeals are affected physically and emotionally for many years afterwards. I suspect you are suffering from post traumatic stress disorder. Symptoms may include nightmares and sexual dysfunction - as well as sleep and eating disorders, social withdrawal, and distrust of others. You must seek help from a qualified therapist.

· Pamela Stephenson Connolly is a clinical psychologist and psychotherapist who specialises in treating sexual disorders.