When we write vectors as matrices, we tend to write an $n$-dimensional vector vector as $n \times 1$ column matrix. We emphasize that the gradient vector is defined only for scalar-valued functions. For vector valued functions, we will stick with viewing the derivative as a matrix.
Gloomy Addiction Relapse Statistics. Drug and alcohol rehab statistics show that the percentage of people who will relapse after a period recovery ranges from 50% to 90%. This is a frightening statistic and it is often used as justification for those who wish to carry on with their addiction.
Alcoholism with 90+ answers. In the long term, when studied with a control group, which has been done several times, the honest answer is not very. There is a wide range depending on what definitions and measurements are used, from a low of 0% effective to a high of around 20% effective. I'm thinking a reasonable assessment would fall closer to the top of that range.