There is a strong link between PTSD and substance abuse. Many folks who have experienced trauma and develop PTSD end up utilizing substances to manage their symptoms. This is because substances offer an immediate relief to many of the symptoms of PTSD. However, as drugs/alcohol do not resolve the underlying trauma, so the substance needs to keep being used to manage and an addiction can arise.
Often substances are used to help with sleep, increase experiences of pleasure, numb painful emotions and allow the person to relax. These are all important goals. It is a common assumption that the only thing needed to be well is to get clean and sober. It is not uncommon for folks I work with to be confused and frustrated that their issues did not resolve when they got sober. The reasons for this is because although they have given up drugs/alcohol, but have not learned any new, healthy coping skills to deal with things, and then all they are left with are the symptoms that led the to use in the first place. People need new ways of managing their emotions and triggers. And it is important that they know it is okay if they choose to gain help from a psychiatrist and get on medications. Fortunately, there seems to be an increasing understanding in the recovery field that this does not negate one’s sobriety. In fact there is a growing recognition of what we call dual diagnosis (those with both mental health and substance use issues) and there are recovery groups specifically for these folks.
There has also been a shift in the last decade or so among the mental health community that there needs to be an integration, understanding and treatment of both mental health issues and substance use issues and not requiring folks to get sober before coming into therapy. I have a lot of experience and comfort in working with folks who are dually diagnosed and am supportive of recovery related activities.