Calm mind can definitely help if you feel your alakazam can take attacks. As you may know calm mind raises Sp.Def and Sp.Atk, but alakazam tends to be especially high in both of those areas already. I would say that unless you are willing to take the gamble of raising your attack and then getting hit, calm mind is a waste of a perfectly good attack opportunity (alakazam does get psychic STAB). It really depends on your Pokémon’s Defense and Hp, but if your confident go for it, this move can max out alakazam’s Sp.atk in time and if your facing an attack oriented Pokemon/trainer alakazam is a Monster!
Hoped this helped