Hi Sir, Welcome to Health Care Magic I can certainly understand your concern and worry about your sexual performance, .I would like to advise you to undergo simple test, as you mentioned that you had suffered from depression, ie NPT test (nocturnal penile tumescence), in which erections occurs in early morning in the sleep which can rule out any problem with your erection.if it is normal, it is unlikely that you have any problem with your erection, on top of it, it is likely that you are having some apprehension towards sex , and you have that guilt feeling , which could part of your depression. previous consumption of cannabis does not affect your current sexual performance.It can be definitely treated perfectly, and notjing to worry Being a psychiatrist , I can advise you some simple tips like....Be relaxed before sex, spend time with foreplay which stimulates the production of nitric oxide NO, to sustain your erection for long time ....And you can start some antidepressant drugs like SSRI s ie escitalopram which helps in reducing your depression and worry, avoid alcohol and smoking if any, maintain adequate weight, try to engage yourself in some physical activity like exercises which helps in production of BDNF ie brain derived neurotropic factor, that keeps you active and stress free through out the day. If these measures does not work, you can try other natural drugs called DHEA (DihydroEpiandrosterone which can improve tour testosterone levels, L-Arginine to increse your NO production, if sildenafil does not solve your problem. Finally, there are other options like penile implants , which is an OP procedure , takes about an hour, vaccum constriction devices, pump with a band on it. The ultimate option is vascular reconstructive surgery . You can consult your psychiatrist for further information. Post your further questions if any, I will available to take up your follow up questions Thank you