The phrase "are drastically different from" is correct and usable in written English.
It can be used to compare two or more things that have significant differences in characteristics or qualities.
Example: "The results of the two experiments are drastically different from each other, indicating that the variables had a major impact on the outcomes."
Alternatives: "are significantly different from" or "differ greatly from".
Their transport properties are drastically different from bulk forms with micron-size grains.
While it may seem obvious, the economic capacities and needs of a nine-year-old girl are drastically different from those of her 15-year-old sister.
The breakthrough curves (BTCs) and distribution profiles in the aquifer obtained in this study are drastically different from those obtained using the AA method.
Here in cosmopolitan England, we'll always have Parris.Political priorities in places like Cambridge (read: most of Britain's cities, many of its suburbs and some of its towns) are drastically different from those in places like nearby Clacton.
However, coefficients of mutual diffusion due to both thermal and shear-induced fluctuations are drastically different from corresponding self-diffusivities as regards both their scaling and their concentrational dependence.
Bellamy shouldn't think that I listen to Mozart (or, for that matter, Schoenberg) or Eric Dolphy or Bud Powell with anything less than my heart and my gut (which, however, I consider inseparable from the brain and the rest of the body)—even though their codes and conventions are drastically different from the ones I was fed with mother's milk.
The menu is drastically different from the old days.
At least, it's drastically different from the garden that could have been.
Do you dream about switching to a career that's drastically different from your current job?
But acknowledging, even accepting, individual frailty is drastically different from being willing to accept that our country is penetrable.
The way the library looks today is drastically different from the way it did 50 years ago.
