In several cases, stimulants, including modafinil, have been reported to have a limited effect on patients, often alleviating sleepiness. They can cause behavioral problems, but they may pose fewer issues if used in older patients with mild symptoms. In some case reports, lithium has been reported to decrease the length of episodes and the severity of their symptoms and to increase the time between episodes. It has been reported to be effective in about 25 to 60 percent of cases. Its use carries the risk of side effects in the thyroid or kidneys. Anti-psychotics and benzodiazepines can help alleviate psychotic and anxiety related symptoms, respectively. Carbamazepine has been reported to be less effective than lithium but more effective than some drugs in its class. Electroconvulsive therapy is not effective and worsens symptoms.