* Clinical psychologists interview patients and give diagnostic tests.

* Psychologists gather information through controlled experiments, personality, projective, performance, aptitude, intelligence and other tests.

* Based on the results they help in diagnosing the illness or identifying the problem.

* They may provide individual, family,
or group psychotherapy.

* They design and implement behavior modification programs.

* Some clinical psychologists collaborate with physicians and other specialists to develop and implement treatment and intervention programs that patients can understand and comply with.