If I am being harassed by other tenants and I have an injunction regarding harassment against them, can I lawfully break my lease?

You might not be be able to get out of your lease without penalty. As a general matter, the landlord is not responsible for the tortious, criminal, or otherwise wrongful acts of unrelated third parties, and their wrongful acts do not provide grounds to terminate your lease, which is a contract.

You are entitled to "quiet enjoyment" of your rental premises, and if the actions of other tenants is violating the covenant of quiet enjoyment and the landlord refuses to take action to address the situation, that *might* provide grounds to terminate the lease. However, the wrongful acts must occur on premises; must be committed by tenants or people demonstrably under the tenants' control; and must be such as any reasonable person would find they ruin quiet enjoyment. Typically, breaches of the right to quiet enjoyment are found in things like excessive noice, late at night, not in personal tension or strife between tenants, since the latter, as it is not a general disturbance of the right to quiet enjoyment, do not involve any actionable failure by the landlord.

You should consult with a landlord-tenant attorney about this matter--the specific facts are critical to determining if you may have grounds to terminate the lease, and that is best assessed by consulting with an attorney. You need to be prepared, however, for the fact that it is unlikely that this harassment, unless it is public disturbances, would breach the covenant of quiet enjoyment or provide grounds to terminate your lease. Issues or tension directly between you other tenants do not implicate the landlord or you lease.