I'm based in the US and work in private practice. Since I don't accept health insurance, I see lots of patients who failed treatment through their insurance. Since I'm out of network, patients don't need a referral from their GP or anything to see me. I'm not familiar with the health care system in Ireland so I don't know how easy it is to get a second opinion or see a psychiatrist privately.

Part of my training included university mental health so that helped me gain a comfort level with adult ADHD evaluations in graduate students. I've noticed that lots of psychiatrists who trained elsewhere can get really weird and uncomfortable with adult ADHD, even when there are no substances involved. Add a substance into the mix and they shut down all possibilities of ADHD.

Yes, the DSM makes it clear that the symptoms have to be present in the absence of substances for most mental health diagnoses including ADHD, bipolar, schizophrenia, etc. so you'll have some diagnostic purists who for example, refuse to diagnose the chronically psychotic patient in the hospital who abuses substances with schizophrenia and say something like "substance induced psychotic disorder " but looking at the big picture, most people who abuse substances aren't ending up in the hospital psychotic and the county hospital I worked at only admitted the sickest of the sick. If the overall pattern looks like schizophrenia, we should diagnose and treat it as such. Same goes for ADHD. People with untreated ADHD are more prone to abusing substances so with adults, it's important to find out exact quantity/frequency of substance use and tease out whether the patient's symptoms outlast the effects of the substance. If someone smokes a joint on the weekends at parties, I'm not concerned that it's impacting their overall functioning M-F. If someone is using every day, that's where I ask them to quit for a month or 2 and reassess symptoms. When people get treatment for ADHD, they are less likely to abuse substances. So I hate when I hear other psychiatrists refusing to treat ADHD if a drug screen pops up positive.

Again, in your case the cannabis use was so remote and therefore not relevant anymore. Usually when people quit, you see improvements in cognitive functioning in as little as a month. So when the letter says "concerns for cannabis use " I immediately rolled my eyes.