I have been on 0.5 mg ativan (lorazepam) since june on an as needed basis..it's for my anxiety...may be i have taken 25 pills since the summer. however, i find it as less effective nowadays.. does it work less since my body is now used to it? should i ask

Although you have: not been taking significant amounts - it may be related to decreased effectiveness. Would encourage other ways to address anxiety. Have you tried cognitive behavioral therapy? Behavior modification? Individual psychotherapy? Group psychotherapy? Qi Gong? Tai Chi? Acupuncture? Acupressure? Homeopathy? Meditation? Yoga? Exercise program? Breathing exercises? Progressive muscle relaxation?

Drug holiday: Although you are not taking it often, you can develop decreased responsiveness to a medication like Ativan (lorazepam). It can help to not take it for a couple of weeks. However if anxiety is an ongoing problem, you deserve more comprehensive treatment. Consider getting a referral to a therapist, or at least starting an anti-anxiety anti-depressant on a regular basis. Talk with your doctor.