Can there be any antidepressants that don't cause weight gain?

Yes, Wellbutrin (bupropion): Welllbutrin is the only one written about not gaining weight.

Antidepressants: Yes, these drugs may cause weight gain but there are several drug options. More important - I hope you are seeing a psychiatrist or a psychologist.

Some do: Many do, but not all. Additionally, if depression caused loss of appetite, one might gain weight having improved.