No, a cult is like a mental disorder... by definition if it's not causing harm in the person's life it's not a disorder. Many cults disguise themselves as religious groups.

Here's some more differentiators, but you can search "warning signs for a cult"... there's no standard list that I'm aware of.

- Separating people from their outsider friends&family

- Over time absorbing all of member's financial assets

- Punishment for leaving

- Members discouraged from questioning orthodoxy

- Non-volunteer or otherwise coerced unpaid labor

- A culture of hiding information from outsiders

- The leader has exclusive claim to ultimate truth

- Regardless of harm, the leader's behavior is justified

1. You generally require a charismatic, authoritarian leader who has strong central command over the group and whose word is law; tenets that actively lead the congregation to act against their best interests; and a dogmatic belief system with strict limits on interpretation of religious teachings (really just the first point again).

2. The classical definition of "cult" has almost no overlap with today's perjorative evolution of the word and just means a system of worship.