The head Exorcist for the Church in Rome says that the Sacrament of Reconciliation is more powerful than exorcism in setting people free. Before every prayer meeting or gathering, take authority over the meeting place in the name of Jesus and with the full authority of His Church. Sprinkle the room and chairs with Holy Water, order the spirits to leave in the name of Jesus, and invite God's Holy Angels to fill the room and help you to give glory to the Father, through the Son, in the power of the Holy Spirit. At any time during the meeting you feel oppression or heaviness, stop and take control of the offending spirits in Jesus' Name. Don't be afraid to use your God given authority.
Souls are at stake.
Obviously, not every illness or emotional problem is due to demonic interference. However, spirits often exert undue pressure in what is a natural problem. Develop a prize fighter mentality. As you gently pray, you probe with your words and wait for the Holy Spirit to identify the enemy. Through experience I know that depression is often due to occult involvement.